Effects of velocity based training vs. traditional 1RM percentage-based training on improving strength, jump, linear sprint and change of direction speed performance: A Systematic review with meta-analysis.

BACKGROUND: There has been a surge of interest on velocity-based training (VBT) in recent years. However, it remains unclear whether VBT is more effective in improving strength, jump, linear sprint and change of direction speed (CODs) than the traditional 1RM percentage-based training (PBT).
OBJECTIVES: To compare the training effects in VBT vs. PBT upon strength, jump, linear sprint and CODs performance. DATA SOURCES: Web of science, PubMed and China National Knowledge Infrastructure (CNKI). STUDY ELIGIBILITY CRITERIA: The qualified studies for inclusion in the meta-analysis must have included a resistance training intervention that compared the effects of VBT and PBT on at least one measure of strength, jump, linear sprint and CODs with participants aged ≥16 yrs. and be written in English or Chinese.
METHODS: The modified Pedro Scale was used to assess the risk of bias. Random-effects model was used to calculate the effects via the mean change and pre-SD (standard deviation). Mean difference (MD) or Standardized mean difference (SMD) was presented correspondently with 95% confidence interval (CI).
RESULTS: Six studies met the inclusion criteria including a total of 124 participants aged 16 to 30 yrs. The differences of training effects between VBT and PBT were not significant in back squat 1RM (MD = 3.03kg; 95%CI: -3.55, 9.61; I2 = 0%) and load velocity 60%1RM (MD = 0.02m/s; 95%CI: -0.01,0.06; I2 = 0%), jump (SMD = 0.27; 95%CI: -0.15,0.7; I2 = 0%), linear sprint (MD = 0.01s; 95%CI: -0.06, 0.07; I2 = 0%), and CODs (SMD = 0.49; 95%CI: -0.14, 1.07; I2 = 0%).
CONCLUSION: Both VBT and PBT can enhance strength, jump, linear sprint and CODs performance effectively without significant group difference.

Introduction

Resistance training plays a pivotal role in enhancing strength, power, linear sprint and change of direction speed (CODs) performance in a wide range of healthy and athletic population [1-3]. It is well known that maximizing the resistance training effects largely depends on the manipulation of the program variables such as the intensity, volume, rest interval, duration, etc [4]. Among them, intensity and volume are the key variables in prescribing the program [4]. Traditionally, the resistance training prescription is based on percentage of one repetition maximum (%1RM) and repetitions, namely traditional 1RM percentage-based resistance training (PBT). Since its introduction by Thomas Delorme in 1940s [5], PBT has been studied and applied extensively, and proved to be an effective method by a huge body of researches. However, PBT has been criticized for the inherent limitations such as the complex process, risk of injury during the maximum strength test [6], and possible attenuation of type Ⅱ muscle fiber adaptation owing to the sets to failure [7, 8], which may result in suboptimal training stimulus.

Over the past decade, there has been a surge of interest in using barbell velocity to measure and monitor the training intensity and volume, i.e. velocity based training (VBT), largely thanks to the major advancements in commercial velocity testing devices such as linear position transducers and accelerometers that allow for immediate feedback of repetition velocity [9]. VBT is a resistance training intervention that uses velocity feedback to prescribe and/or manipulate training load. Two new variables are adopted for prescribing the training load in VBT, one is the initial fastest repetition velocity in sets to set the load instead of %1RM, the other is the velocity loss threshold (VL) to terminate the set instead of the traditional fixed repetitions in sets. Compared with PBT, VBT has several compelling features. Firstly, velocity can be attained to estimate the 1RM and regulate the intensity in real time to match the actual intention for the particular session regardless of the fluctuation of personal 1RM due to the fatigue, nutrition, sleep etc [9]. Secondly, monitoring the velocity loss in training set can assist to control the levels of efforts and fatigue in a certain range and make the lifted repetitions correspond well with the training specificity [6, 10]. Thirdly, instantaneous augmented feedback of velocity following each lifting repetition could motivate the athletes to enhance acute physical performance and improve adaptation accumulatively [11, 12]. Therefore, based on these advantages, it could be argued that the VBT would be more effective in improving physical performance than PBT. However, the answer to this question remains unclear so far.

Previous studies reported that both VBT and PBT could improve physical performance effectively [13-16]. More recently, some scattered researches have been carried out on comparing the training effects of VBT vs. PBT [17-21]. However, these researches to date have not been able to provide robust evidence for telling the distinctions of training effects on improving physical performance between VBT and PBT. For example, some studies confirmed that VBT improved strength more effectively than PBT due to the above-mentioned advantages [17], while the others demonstrated no significant differences between VBT and PBT [20, 22], and one study even reported a better effect in PBT [18]. Therefore, a systematic review with meta-analysis is warranted to draw a conclusion from the inconsistency.

The purpose of this study was to determine whether VBT was more effective than PBT in enhancing strength, jump, linear sprint and CODs. The hypothesis was that VBT would improve these outcomes better than PBT with a small effect. To the author’s best knowledge, this is the first study to compare the effects of VBT vs. PBT by meta-analytic techniques. Our findings should enhance greater understanding about the different training effects and assist the practitioners to make better selection between VBT and PBT.

2 Methods

This systematic review and meta-analysis was conducted under the Preferred Reporting Items for Systematic Reviews and Meta-Analysis Protocol (PRISMA).

2.1 Search strategy

The first author searched the potential articles from PubMed, Web of Science and CNKI (China National Knowledge Infrastructure), up to January 6th, 2021. The following three English terms combined under Boolean syntax were applied in PubMed and Web of Science: term 1 “Velocity based training”, VBT, velocity, speed, resistance; term 2 “Strength training”, “power training”, “resistance training”, “percentage based training”; term 3 Strength, power, performance, “change of direction”, agility, endurance, speed, sprint. Given the different language context, we adjusted the Chinese searching terms applied in CNKI as following: term 1: “基于速度的力量训练”(velocity based training), “速度负荷” (Velocity load); Term 2: 力量(strength), 抗阻 (resistance). The searching strategy and syntax are shown in S1 Table. Forward citation and reference lists of retrieved full texts articles were checked by hand searching to identify potential eligible studies that were not found by the initial search.

2.2 Eligibility criteria

Original research articles were eligible if they met the following eligibility criteria: 1) prospective randomized or non-randomized comparative trial; 2) implemented both VBT and PBT interventions; 3) the training interventions lasted at least 4 weeks; 4) the training frequency for both interventions was at least 2 times per week; 5) participants were healthy and aged ≥16 yrs.; 6) measures of muscle strength, jump, linear sprint or CODs performance was assessed before and after the intervention (minimum follow-up period of 4 weeks); 6) full-text was available in English or Chinese. VBT was defined as a resistance training intervention that uses velocity feedback to prescribe and/or manipulate training load. Movement velocity could be measured with a linear position transducer, inertial sensor, force platform, and/or motion capture. PBT was defined as a resistance training intervention that prescribed training load based on a %1RM that was assessed at pre-intervention. We broadly defined resistance training as a sequence of dynamic strength exercises that utilized concentric and eccentric muscular contractions.

2.3 Outcomes

Outcomes were surrogate measures of physical performance. If the same study reported more than one outcome in the same outcome domain, we only extracted a single most relevant effect size to deal with the multiplicity according to a decision rule as following: 1) the most used test in included studies; 2) selected comparison with performance tests in accordance with resistance training practice (e.g. lower body performance > upper body performance; dominant leg > non-dominant leg); 3) selected estimates from randomized in preference to non-randomized comparison. Muscle strength outcomes included back squat or bench press 1RM tests, as well as barbell velocity outcomes included measures of load velocity profile (LVP) obtained at a specific relative load in the concentric phase of the back squat. Linear sprint included a timed maximal sprint between 5 and 30 meters in distance. CODs included a timed, pre-planned COD task characterized by a maximal sprint followed by a deceleration and re-acceleration to a new direction. We also included jump performance as an outcome. All outcomes were continuous measures.

2.4 Study selection

After the literature searches were complete, studies were collected into a single list using Endnote software (X9.3.3). The fourth author removed any duplicates, then the third and the fourth authors independently screened the titles and abstracts to exclude any unrelated articles, with the remaining full texts screened against the eligibility criteria by two authors (the second and the third author). Any conflict regarding selection of articles was resolved by consensus. Corresponding authors were contacted if a full-text manuscript could not be retrieved or to clarify aspects of the study in relation to the inclusion criteria.

2.5 Risk of bias assessment within individual studies

Two authors (the second and the fourth author) independently evaluated the risk of bias within included studies, with disagreements resolved by discussion and consensus. Kappa coefficient was applied to evaluate inter-raters’ agreement. The result showed that the agreement was high (Kappa coefficient = 0.83).

Given lots of risk of bias assessment scales (Cochrane scale, Delphi scale, Pedro scale) are specialized for medical research, trials in sport science usually were evaluated as poor quality in accordance with these methodological scales [23]. We chose the scale (S2 Table) modified by Brughelli et al. [23] and Hooren et al. [24]. This scale is deemed more suitable for sport science research, and includes 10 items, with each item rated as: 0 = clearly no/not reported, 1 = maybe, and 2 = clearly yes. The articles were rated poor with a total score lower than 10, moderate with a score between 10 and 15, good with a score > 15, and excellent with a score equal to 20. Publication bias was evaluated by regression-based egger test of the intercept for small-study effect and visually inspecting a funnel plot.

2.6 Data extraction

All data were independently extracted by two authors (the third and the fourth author) to a data collection form in Excel (Microsoft Corporation, Redmond, Washington, USA). Any discrepancy between two authors was resolved by discussion and consensus. Data items included: 1) participant characteristics, 2) sample size, 3) details of VBT and PBT interventions, 4) length of follow-up, 5) details of the outcome measure(s), 6) details of dropout rates, intervention adherence and adverse events, and 7) pre- and post-intervention data for each outcome measure (mean and SD). Study authors were contacted to obtain missing data wherever necessary.

2.7 Quality of evidence

The quality of evidence for each included outcome was rated using the evidence grading system developed by the Grades of Recommendation, Assessment, Development, and Evaluation (GRADE) collaboration. GRADE has four levels of evidence: very low, low, moderate and high. Pooled outcomes that included only randomized trials started with a ‘high quality’ rating, whereas pooled outcomes that included data from at least one non-randomized trial started with a low-quality rating. The evidence was then downgraded for each outcome based on the following domains: 1) risk of bias, 2) inconsistency of results, 3) indirectness of evidence, 4) imprecision of results, and 5) publication bias. The evidence was downgraded by one level if we judged that there was a serious limitation or by two levels if we judged there to be a very serious limitation. One authors (the first author) judged the quality of evidence. An overall GRADE quality rating was applied to the body of evidence by taking the lowest quality of evidence from all of the outcomes. Judgments about evidence quality were justified and documented within a GRADE evidence profile.

2.8 Statistical analysis

The review manager software (5.3) was applied for the meta-analytic. Random effects model for all outcomes was chosen to aggregate the effect size. Chi2 and I2 were calculated to test the heterogeneity. For I2 values of 25, 50, and 75% represent low, medium, and high heterogeneity, respectively [25]. For Chi2 with large value and p < 0.1 show evidences of heterogeneity. If p > 0.1 and I2 < 50% provoked further investigation through a subgroup analysis of moderator variables (training experience, identity, gender, training frequency, training modalities, training weeks). In order to identify the presence of highly influential studies, a sensitivity analysis was executed by removing one study at a time. Studies were considered as influential if removal resulted in a change of heterogeneity (p) from significance (p < 0. 1) to non-significance (p > 0.1).

If the same measures were applied in the same outcome, pooled mean difference (MD) was calculated with the intervention group’s MD (mean difference from pre-test to post-test) and SDpre. Otherwise, the SMD was calculated by dividing the MD by the pooled SDpre [26], the algorithm is as following: This algorithm was selected as it has been recommended for effect size calculation of independent pre-/post- study designs in meta-analysis based on simulation results. Both algorithms of MD and SMD in speed and COD outcomes were adjusted as [Mpre—Mpost], of which the smaller values represents better results compared with other outcomes. Statistical significance was set at p < 0. 05. The absolute values of effect sizes were rated with the following criterion given by Cohen [27]: <0.2 as trivial, 0.2–0.49 as small, 0.5–0.79 as moderate, ≥0.8 as large. Values were reported with 95% confidence intervals to describe the range of the true effect. If the absolute value of aggregated effect and 95% confidence interval were above zero, effect size could be considered as clear evidence. A positive effect size indicated that the effect of VBT was more effective in improving the performance than PBT, and a negative effect size indicated the opposite, i.e. PBT more effective than VBT. SMDs were also applied to do the funnel plot so that all estimates can be put into one plot.

3 Results

3.1 Search results

The initial search resulted in 6533 records in English and Chinese. After excluding 2485 duplicates, 4048 records screening by the title and abstract, 3987 papers were subsequently excluded. The remaining 61 articles were read in full-text for eligibility. At last, 6 studies were included in the qualitative and quantitative analysis. These data are presented in Fig 1.

Fig 1

Flow chart illustrating the different phases of the search and study selection.

WOS, web of science; CNKI, China National Knowledge Infrastructure; VBT, velocity-based training; PBT, Percentage-based training.

3.2 Risk of bias assessment

According to the modified scale, the scores of the 6 included studies ranged from 10 to 17, the overall quality was moderate, 3 studies were rated as good [17, 20, 28], and 3 studies were rated as moderate [18, 22, 29]. All studies got high scores in item 5, 7 and 9, but no study adopted a control group (see Table 1). The funnel plot show that the effects were symmetric distributed around the overall pooled effect size (see Fig 2). Egger’s test of the intercept indicated that there was no small-study effect (β = -0.24; 95%CI -3.67 to 5.8; p = 0.64).

Table 1

The results of risk of bias assessment.

Studies	Items
	1	2	3	4	5	6	7	8	9	10	Score
Chen Song et al.,	1	1	0	2	2	0	2	0	2	0	10
Wang Zhihui et al.,	2	2	2	2	2	0	2	2	2	1	17
Dorrell et al.,	2	2	2	2	2	0	2	1	2	1	16
Orange et al.,	2	2	2	1	2	0	2	0	2	1	14
Banyard et al.,	2	2	0	2	2	0	2	1	2	2	15
Held et al.,	2	2	2	2	2	0	2	1	2	1	16

Fig 2

The funnel plots.

LVP, load velocity profile; RM, repetition of maximum.

3.3 Studies’ characteristics

The characteristics of 6 studies included in qualitative analysis were displayed in Table 2. A total of 124 subjects were included in the research, with age ranging from 16 to 30 yrs. The intervention duration ranged from 6 to 8 weeks with a training frequency of 2 to 3 sessions per week. Among which, only 1 study had 3 sessions per week [22]. All studies took back squat as the intervention exercise, 2 studies also adopted other exercises such as bench press and deadlift [17, 20]. The intensity of the resistance training ranged from 43% to 95%1RM or correspondent velocity. The sets were equal in both VBT and PBT groups ranging from 3 to 10. Four studies had the same repetitions in both groups ranging from 2 to 10, while 2 studies used the different repetition scheme, among which, 1 study adopted velocity loss [17] and 1 study used both fixed repetition and velocity loss as the termination of the sets [20]. The outcome measures included tests of maximum strength, power, barbell velocity, force, maximal oxygen uptake (VO2max), linear sprint and CODs. All studies tested the back squat 1RM, while 4 studies tested countermovement jump (CMJ) tests [18, 20, 22, 28], and 3 studies tested speed [18, 22, 28]. In addition, 2 studies tested CODs [22, 28] and load velocity [18, 22], and 1 study tested the VO2max [17]. Four studies reported the sessional measures such as total volume, RPE, time under tension, barbell mean velocity and mean power [17, 18, 20, 22].

Table 2

The characteristics of the included studies.

Study	Study Design	Participants						Interventions						Outcome Measure
		Identity	Training Experience (years)	Age (years)	Sex	N	Drop out rate	Frequency (times/week)	Weeks	Sets	Exercises	Reps	Intensity (%1RM)	Performance test
Orange 2019	Randomized	Rugby players	≥2	17±1	M	27	VBT: 25% PBT: 6.25%	2	7	4	Back squat	5	VBT: velocity at 60–80% 1RM PBT:60–80%RM	**Back squat 1RM CMJ, Drop jump LVP-40%,*60%,80%,90%1RM **10,20,30m sprint *Sessional mean velocity *Sessional mean power *sessional TUT *sessional RPE
Banyard 2020	Non- randomized	Resistance-trained	≥2	25.5±5	M	24	0%	3	6	5	Back squat	5	VBT: velocity at 59.9–69.4% 1RM PBT: 59–85%	Back squat 1RM *PV-CMJ LVP-20%,40%,60%,80%,90%,100%1RM *5, *10, *20m sprint 15m shuttle *Sessional mean velocity *Sessional mean power *Sessional TUT *Sessional RPE
Song Chen1995	Non- randomized	College athletes	--	18–22	F	20	VBT: 20% PBT: 20%	2	8	4	Back squat	VBT:6–10 PBT:6–9	VBT: Velocity at Maximum power load PBT:60–75%1RM	Back squat 1RM Maximum Force Peak Velocity Peak power
Zhihui Wang 2020	Randomized	Basketball players	3.20±0.42	20.1±0.88	M	20	0%		2	4	Back squat	6	VBT: velocity at 75% 1RMPBT: 75%1RM	Back squat 1RMCMJ10 yard sprint*T test
Dorrell 2019	Randomized	Resistance-trained	≥2	22.8±4.5	M	16	Total: 46.7%	2	6	3	Back squatBench pressOHPDeadlift	2–82–82–82–8	VBT: Velocity at 70–95%1RMPBT: 70–95%1RM	Back squat 1RM*Bench Press 1RMOHP 1RMDeadlift 1RM*CMJ*Total volume
Held 2021	Randomized	Rowers	≥2	19.6 ±2.1	FM	417	VBT:45.5%PBT:60%	2	8	4	Power cleanBack squatBench RowDeadliftBench press	VBT: 10%VLPBT: Sets to failure	VBT: velocity at 80% 1RMPBT: 80%	*Back squat 1RM*Bench Row 1RMDeadlift 1RM*Bench press 1RMVO2MAXPVO2MAX*Total repetitions*Change of overall stress*Change of overall recovery

F, female; M, male; Reps, repetitions; PBT, percentage-based training; VBT, velocity-based training; N, number of participants; RM, repetition maximum; OHP, Overhead press; LVP, load velocity profile; TUT, time under tension; RPE, rating of perceived exertion;

*, in favor of VBT;

**, in favor of PBT

3.4 Quantitative analysis

The performance tests in the included studies could be categorized into 4 kinds after dealing with the multiplicity (Table 3), including strength consisted of back squat 1RM and load velocity with 60%1RM, CMJ, linear sprint and CODs. The evidences quality was low. These data were showed in Table 4.

Table 3

Performance indicators of included studies.

Study	Outcome	Performance indicators	Selected for meta-analysis
Dorrell et al.,	strength	Back squat 1RM	√
		Bench press 1RM
		Deadlift 1RM
		Overhead press 1RM
Held et al.,	Strength	Back squat 1RM	√
		Bench press 1RM
		Deadlift 1RM
		Bench row 1RM
Orange et al.,	Jump	Countermovement jump	√
		Squat jump
	Speed	10m	√
		20m
		30m
	Load velocity	40%1RM	√
		60%1RM
		80%1RM
		90%1RM
Banyard et al.,	Speed	5m
		10m	√
		20m
	Load velocity	20%1RM
		40%1RM
		60%1RM	√
		80%1RM
		90%1RM
		100%1RM
	Change of direction	Dominant leg 15m shuttle	√
		Non-dominant leg 15m shuttle

Table 4

GRADE of evidence profile.

Summary of findings				Quality assessment
Outcome	No. of participants (studies)	Pooled effects (95%CI)	I2	Risk of bias	Inconsistence	Indirectness	Imprecision	Publication bias	Quality rating
Back squat (kg)	124(6)	3.03(-3.55, 9.61)	0%	Serious limitationa	No serious inconsistence	No serious in indirectness	No serious imprecision	Undetected	Low
LVP60%1RM (m/s)	51(2)	0.03 (-0.01, 0.07)	0%	Serious limitationa	No serious inconsistence	No serious in indirectness	No serious imprecision	Undetected	Low
CMJ	87(4)	0.27(-0.15, 0.70)	0%	Serious limitationa	No serious inconsistence	No serious in indirectness	No serious imprecision	Undetected	Low
Linear sprint (s)	71(3)	0.01 (-0.06, 0.07)	0%	Serious limitationa	No serious inconsistence	No serious in indirectness	No serious imprecision	Undetected	Low
CODs	44(2)	0.46(-0.14, 1.07)	0%	Serious limitationa	No serious inconsistence	No serious in indirectness	No serious imprecision	Undetected	Low

a, one studies included in the outcome was non-randomized design; LVP60%1RM, load velocity profile with 60% one repetition maximum; CMJ, countermovement jump; CODs, change of direction speed

3.4.1 Strength

1) Back squat 1RM. The pooled results from 6 studies consisting of 124 participants suggested that there was no significant difference in improving back squat strength between VBT and PBT (p = 0.37). The heterogeneity was low (Chi2 = 4.28, p = 0.51; I2 = 0%). In random effects model, aggregated MD and 95%CI were 3.03kg (-3.55, 9.61) in favor of VBT. These data were showed in Fig 3A.

Fig 3

Forest plot of the results on strength performance (A), Load velocity 60%1RM (B), jump performance (C), linear sprint performance (D) and change of direction speed performance (E).

2) Back squat LVP with 60%1RM. LVP with 60%1RM was chosen because 1m/s (~60%1RM) was usually used to evaluate the performance in resistance training [22, 30]. The pooled results from 2 studies consisting of 51 participants indicated that there was no significant difference in improving LVP60%1RM between VBT and PBT (p = 0.21). The heterogeneity was low (Chi2 = 0.96, p = 0.33; I2 = 0%). In random effects model, aggregated MD and 95%CI were 0.02m/s (-0.01, 0.06) in favor of VBT. These data were showed in Fig 3B.

3.4.2 CMJ

The SMD was calculated due to one study using peak velocity as testing value. The pooled results from 4 studies consisting of 87 participants indicated that there was no significant difference in improving CMJ between VBT and PBT (p = 0.21). The heterogeneity was low (Chi2 = 0.16, p = 0.98; I2 = 0%). In random effects model, aggregated effect size and 95%CI were 0.27 (-0.15, 0.70) classified as a small effect in favor of VBT. These data were showed in Fig 3C.

3.4.3 Speed

The pooled results from 3 studies consisting of 71 participants indicated that there was no significant difference in improving speed between VBT and PBT (p = 0.86). The heterogeneity was low (Chi2 = 1.58, p = 0.45; I2 = 0%). In random effects model, aggregated MD and 95%CI were 0.01s (-0.06, 0.07) in favor of VBT. These data were showed in Fig 3D.

3.4.4 CODs

The SMD was calculated due to both included studies with different tests. The pooled results from 2 studies consisting of 44 participants indicated that there was no significant difference in improving CODs between VBT and PBT (p = 0.13). In fixed effects model, the heterogeneity was low (Chi2 = 0.41, p = 0.52; I2 = 0%). aggregated effect size and 95%CI were 0.46 (-0.14, 1.07) classified as a small effect in favor of VBT. These data were showed in Fig 3E.

4 Discussion

This systematic review with meta-analysis aimed to compare the training effects of VBT vs. PBT on measures of strength, jump, linear sprint and CODs performance. The results showed that both VBT and PBT were effective, with little to no difference between VBT and PBT. However, all pooled effects demonstrated a trend in favor of VBT, which did not support our hypothesis well.

4.1 Strength performance

Both VBT and PBT produced similar gains in squat 1RM, with minimal differences presented in mean changes (3.03kg, 95%CI:-3.55, 9.61) in favor of VBT. The result was similar to a recently meta-analysis by Davis who reported that maximal and moderate velocity exhibited similar improvement in muscular strength. However, the effect (ES = 0.31; 95%CI:-0.01, 0.63) was small in favor of higher velocity with the same intensity ranging 60%-79%1RM [31]. The squat is one of the exercises most frequently adopted for enhancing and evaluating physical performance and health due to its similarities of biomechanics to a various of key sports and daily tasks [32, 33]. Interestingly, all included studies of this systematic review applied squat as the main intervention exercise. It is clear that a change in the muscle cross sectional area (CSA) and an enhanced neural adaptation are the two key factors for the improvement of maximum strength [16, 34]. However, to date, there has been a paucity of study conducted to compare the difference on improving muscle mass between VBT and PBT, excepted one study by Fernandez Ortega et al. which demostrated that both VBT and PBT could significantly increase children’s (13.6±1.2 years) muscle CSA, but without group difference [21]. Of note, with participants aged under 14 yrs, caution must be applied, as the finding might be limited by the growth effect. Thus, it is still not clear which method is more effective in improving muscle CSA in adults. However, Orange et al. and Banyard et al. both reported that VBT performed significant higher sessional mean velociy and mean power compared to the PBT (ES = 1.25) with the same verbal encouragement for participants’ maximal voluntary efforts [18, 22]. the results were likely the consequences of subtle decreases in load [19], and placebo effect from the velocity testing device in VBT group. Although the researches conducted by Chen et al. and Held et. al. did not provide the repetition velocity data in sessions [20, 29], it could be expected that participants with feedback of repetition velocity in sessions might perform even higher repetition velocity than PBT [12]. Furthermore, interstingly, 4 of the 6 included studies reported that VBT had lower training volume contrasting to PBT with load range 59% to 95%1RM [17, 18, 20, 22]. For example, Held et al. reported that the total repetitions of VBT group were only 77%% of PBT group [17]. Similarly, of 3 studies reported VBT produced lower training stress [17-19], this is likely explained by the reason that the mean time under tension of VBT was significant less than PBT, which might lead the reduction of mechanical stress correspondently to the practitioners [18, 19]. It is plausible that the lower volume and perceived training stress also contributed partly to the higher repetition velocity owing to participants’ less fatigue and need for recovery. Held et al. demostrated that the indicators of overall recovery and stress after 24 and 48 hours in VBT were superior to PBT via a validated daily questionnaire [17]. These two factors were also contributed to the higher repetition velocity. Due to these differences, the muscle fast fibres are likely to be selectively recruited more when performing faster repetition with the similar load by maximum voluntary efforts. Taken together, it might be inferred that VBT and PBT enhanced strength through different mechanism. VBT should produced a better stimulus for neural adaptations owing to higher repetition velocity and lower training stress, while it was likely for PBT to produce better adaptation in muscle morphology due to higher mechanical and metabolic stress. These influencing factors might be mutually offsetting to result in the similar effects on enhancing squat 1RM between VBT and PBT.

In the past decades, a growing body of studies established that completing more repetition or training to muscle failure with heavy load training might not be essential for greater improvements in muscle strength and hypertrophy in comparison with lower training volumes [8, 35–39]. Conversely, training to muscle failure might even reduce myosin heavy chain ⅡX percentage [40]. Recently, Banyard et al. reported that there were little to no difference in the average training load between VBT (69.2±7.2%1RM) and PBT (70.9±7.4%1RM) in 6 weeks of back squat training in a daily undulating model [22]. The similar result was also found by Held et al [17]. Furthermore, evidences indicated that exercise repetitions executed at maximum intended velocity could result in greater improvements in 1RM and power in comparison with the sub-maximal owing to enhancing motor unit firing rate and stimulating the highest threshold type Ⅱ fiber which have a greater relative hypertrophy than type Ⅰ fiber [30, 41–43]. Collectively, regardless of the difference in volume, almost similar load and higher velocity specific stimulation in neural muscular adaptation for above mentioned factors could be the major reason, if not the only one, causing the results on strength in favor of VBT compared to PBT.

The results showed that the MD (0.02m/s) of individual squat LVP 60%1RM was negligible between VBT and PBT, which was even less than the measurement error of the velocity testing device [44]. This finding supported that LVP would keep stable against the same relative load after short term training. Gonzalez-Badillo et al. indicated that the individual LVP would remain stable (MD = 0.01m/s) in pre and post-interventioin test irrespective of a mean 1RM improvement of 9.3% in 6 weeks strength training [9]. Although one of the included studies by Banyard et al. indicated that both groups can improve the barbell mean velocity against the absolute load after 6 weeks training [22]. Considering the methodology involved the use of post minus pre intervention value in our meta-analysis, it could be speculated that difference would be close to zero owing to the reliable individual LVP against the same %1RM in short term training. Of note, the effect was only pooled by two studies from traditional resistance model, more researches from different training model such as power training are needed to explore the difference on improving both absolute and relative load velocity between VBT and PBT.

4.2 Jump performance

The results demostrated that VBT was superior to PBT in CMJ with no significant difference. Previous studies indicated that motor unit recruitment and discharge rate, and muscle fiber type composition were the determinants for the rate of force development [45] and efficacy of muscle-tendon stretch-shortening cycle (SSC), which were considered as the main factors for improving CMJ performance. As explained earlier, VBT was characterized with a higher velocity, lower volume and training stress in each session. Consequently, an enhancement in neural drive to agonist and SSC efficacy could be expected [37, 38]. Comparatively, training to muscle failure in PBT may induce undue fatigue and generate sub-optimal training stimulus, which may lead the adaptations towards slower and endurance resistant fiber types, and impair the rate of force development [38]. Furthermore, Banyard et al. reported that the mean deviation of sessional repetition velocity was greater for the PBT (-13.6 ± 6.8%) contrasted to VBT (-0.2 ± 5.2%) [22]. There is also evidence that the greater consistence of high repetition velocity was superior enhancements in rapid actions [46]. Cumulatively, it should be expected that VBT with lower variability in sessional repetition might have better training effect. Besides, the squat as the main intervention exercise was similar in biomechanics to the CMJ. Although, it is hard to perform sets of repetitions at fast velocity in heavy load as CMJ. Under the velocity specificity of resistance training [47], the higher movement velocity with the maximum voluntary efforts in VBT was likely to result in better transference to CMJ performance compared to PBT. Taken together, it could be speculated that VBT might produce superior change in jump performance compared to PBT.

4.3 Linear sprint and CODs performance

The MD in linear sprint was negligible (0.01s) between VBT and PBT. Previous evidence showed that the squat maximum strength existed very large correlation (r = -0.77; p = 0.001) with the sprint performance [48]. Thus, it could be inferred that the similar improvement of strength between VBT and PBT as above mentioned may be the reason for this negligible result. Furthermore, in line with the concept of training specificity, the intervention program without linear sprint training and horizon oriented resistance exercises may lead the lack of specificity transference to the tests measures, which in combination with the relatively short training duration may also impair resistance training adaptations to sprint performance measures [49]. Besides, one included research by Orange et al. found that sprint performance was impaired in both groups. Under the author’s explaination, it may be attributed to the accumulated match fatigue in competitive season [18]. This negative effect may also impact the pooled results methodologically. Overall, the similar change of stength, lack of specificity transference and methodological difference of included studies may be the main factors for these negligible results. Of note, there was a paucity of research carried out to compare the different effects on enhancing linear sprint between VBT and PBT, more researches are still needed to distinguish the difference.

The result was in favor of VBT on enhancing CODs with a small effect. However, there was insufficient number of studies to pool the magnitude of effects on CODs in VBT vs. PBT. Of the 2 studies that compared changes in this outcome measure, Banyard et al. indicated that the effect in CODs (ES = 0.67–0.79) favored VBT compared to PBT [22]. Similarly, Wang et al. demonstrated that CODs was the only measure that VBT was superior to PBT [28]. The possible explaination for this result may be the same as above mentioned such as the higher and more consistent repetition velocity. Whether the pooled effect would be enlarged in favor of VBT via more search remains to be determined in future.

From a practical view, irrespective of achieving the similar effects as PBT in enhancing maximum strength, CMJ, linear sprint and CODs performance, VBT had significant lower volume and training stress, and better recovery. This implies that pactitioners are likely more enjoyable with VBT, which might also affect long-term adherence. Furthermore, as mentioned in introduction part, VBT has several compelling features such as estimating the load by highest repetition velocity in real time, controlling the level of fatigue by velocity loss in sets and augmenting motivation by feedback of repetition velocity. Besides, Hopkins et al. stated the smallest worthwhile enhancement by 10% will help the athletes to win the game [50]. Thus, if the facilities are available, it may be expected that VBT could be preferred over PBT.

4.4 Limitations

We acknowledge that there are some limitations in this study. One major drawback is the small number of studies included in meta-analysis, which may prevent us from meta-regression and moderator ananlysis. It is hoped that this limitation will be diluted with more studies conducted in the future. Another limitation is the age of included participants ranging from 16 to 30 yrs. Therefore, our findings are difficult to be extrapolated to all practitioners beyond this range of age. However, our intention was to explore the knowledge on the topic with particular emphasis on the athletic population. Due to one quasi-control study, all results were graded as low quality in accordance with GRADE. Futher rigorously designed randomized control studies are warranted to provide robust evidence. Besides, we only searched the studies written in English and Chinese, thus, some relevent articles in other language would be missed.

5. Conclusion

In conclusion, both VBT and PBT were effective in enhancing strength, jump, linear sprint and CODs performance. Although there was no signifincat difference between VBT and PBT upon improving each outcome measures, VBT exhibited lower volume and training stress than PBT. VBT could be more suitable when athletes are suffering from busy training and competition schedule, and for those who would like to focus on enhancing power. In addition, given the less exhaustive nature of VBT, this training may help to mitigate the interference of concurrent endurance and strength training on training adaptations.

(XLSX)

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(DOCX)

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(DOCX)

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(DOCX)

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15 Jun 2021

PONE-D-21-12316

Effects of Velocity Based Training vs. Traditional 1RM Percentage-based Training on Improving Strength, Jump, Linear and Change of Direction Speed Performance: A Systematic Review with Meta-analysis

PLOS ONE

Dear Dr. Li,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

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PLOS ONE

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China Institute of Sport Science Basic Foundation [Basic 17-30]."

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Reviewer #1: Yes

**********

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Reviewer #1: Yes

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Reviewer #1: Yes

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Reviewer #1: First of all, thank you for the opportunity to review this well-written meta-analysis. The methods are clearly presented and the results are also interpreted and discussed accordingly. Nevertheless, I have the following specific comments:

Site and Line numbers would simplify the review process considerably.

Abstract:

“However, VBT can achieve a similar training effect with lower training volume and stress.” → Even though I agree with this statement, this is not a result of this meta analysis

Keywords: I would recommend using keywords that are not already used in the abstract. This may increase the reach of the paper.

Introduction:

“VBT was a resistance training intervention that uses velocity feedback to prescribe and/or manipulate training load based on the perfect inversely linear relationship between load and repetition velocity, and nice correlation between velocity loss and maximum repetitions, as well as the %maximum repetitions and level of fatigue in sets,two new variables were adopted for prescribingthe training load in VBT, one is the initial fastest repetition velocity in sets to set the load instead of%1RM, the other is the velocity loss threshold (VL) to terminate the set instead of the traditional fixed repetitions sets.” → This sentence is way to long. Please rewrite this.

“More recently, some scattered researches have been carried out on comparing the training effects of VBT vs. PBT.” → A reference is needed for this sentence.

“One possible explanation is that the effects of the resistance training intervention on physical performance could be affected by several participants’ characteristics such as the initial training status or chorological age, while the other is the differences in resistance training variables such as the exercises, duration, periods, intensity and volume. Specifically, some studies adopted the fixed repetitions schemes to terminate the set in VBT group, whereas others used fixed velocity loss value either separately or in combination with the former.” → I would expect such explanations in the discussion section.

Methods:

The representation of the search strategy is somewhat confusing. why, for example, was "endurance" searched for? A tabular representation might be easier to read and understand.

“Quality of evidence” Is this not (at least partially) redundant to the Pedro score?

“Statistical analysis” → I would mention CHI^2 and I^2 only after the Ramdom effects model has been described.

The formula for SMD is wrong (or is displayed incorrectly).

Results:

were the reference lists of the resulting 6 studies checked for potential additional studies?

please avoid redundant information between text and tables/figures. Also there are some irrelevant informations like (“The MD was calculated.”)

“LVP with 60%1RM was chosen because 1m/s (60%1RM) was usually used to evaluate the performance in resistance training. “ → This sentence needs a reference.

Discussion:

Recheck spelling & grammar

Table 3 is not necessary. In comparison to table 2, no additional information is provided here.

The symmetry of the funnel plot could be additionally checked by egger's p Value.

**********

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Reviewer #1: Yes: Steffen Held

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17 Jul 2021

July 7th 2021

Dear Professor Daniel Boullosa

thank you for your letter and the comments from the reviewers with regards to our paper submitted to PLOSONE.

We have carefully checked the manuscript and revised it under the reviewer’s comments. With this letter we submit the modified version as well as the list of changes we have made.

If you have any question, please let me know.

Thank you once again for your feedback.

Sincerely,

Professor Yongming Li

Response to editor’s comments:

Thanks for your comments on our paper. We have revised our paper according to your comments.

Journal Requirements:

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https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and

Response: we have corrected it based on those requirements. Thank you.

2. Thank you for stating the following in the Title page of your manuscript:

"This work was supported by the Winter Olympics Foundation [2018FF0300901];

China Institute of Sport Science Basic Foundation [Basic 17-30]."

We note that you have provided funding information that is not currently declared in your Funding Statement. However, funding information should not appear in the Acknowledgments section or other areas of your manuscript. We will only publish funding information present in the Funding Statement section of the online submission form.

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Please include your amended statements within your cover letter; we will change the online submission form on your behalf.

Response: We have already deleted it in title page, and put it into our cover letter. Thank you.

Please find below the new statement

"This work was supported by the Winter Olympics Foundation [2018FF0300901];

China Institute of Sport Science Basic Foundation [Basic 17-30] funds to Yongming Li."

Response to reviewer #1:

Thanks for your comments on our paper. We have revised our paper according to your comments.

Reviewer #1: First of all, thank you for the opportunity to review this well-written meta-analysis. The methods are clearly presented and the results are also interpreted and discussed accordingly. Nevertheless, I have the following specific comments:

Site and Line numbers would simplify the review process considerably.

Abstract:

1 “However, VBT can achieve a similar training effect with lower training volume and stress.” → Even though I agree with this statement, this is not a result of this meta analysis

Response: We agree with this, and we have deleted this statement from the conclusion. Thank you.

2 Keywords: I would recommend using keywords that are not already used in the abstract. This may increase the reach of the paper.

Response: We agree with it and we have replaced the keywords. The key words that we are now using are: load, velocity loss, athletic performance, resistance training, muscle strength.

Introduction:

1 “VBT was a resistance training intervention that uses velocity feedback to prescribe and/or manipulate training load based on the perfect inversely linear relationship between load and repetition velocity, and nice correlation between velocity loss and maximum repetitions, as well as the %maximum repetitions and level of fatigue in sets, two new variables were adopted for prescribing the training load in VBT, one is the initial fastest repetition velocity in sets to set the load instead of%1RM, the other is the velocity loss threshold (VL) to terminate the set instead of the traditional fixed repetitions sets.” → This sentence is way to long. Please rewrite this.

Response: We have re-written this section and we have made it shorter. Thank you.

2 “More recently, some scattered researches have been carried out on comparing the training effects of VBT vs. PBT.” → A reference is needed for this sentence.

Response: The references have been added. They are as following:

(1) Held, S., et al., Improved Strength and Recovery After Velocity-Based Training: A Randomized Controlled Trial. Int J Sports Physiol Perform, 2021: p. 1-9. Orange, S.T., et al., Effects of In-Season Velocity- Versus Percentage-Based Training in Academy Rugby League Players. Int J Sports Physiol Perform, 2019: p. 1-8.

(2) Banyard, H.G., et al., Comparison of the Effects of Velocity-Based Training Methods and Traditional 1RM-Percent-Based Training Prescription on Acute Kinetic and Kinematic Variables. Int J Sports Physiol Perform, 2019. 14(2): p. 246-255.

(3) Dorrell, H.F., M.F. Smith, and T.I. Gee, Comparison of Velocity-Based and Traditional Percentage-Based Loading Methods on Maximal Strength and Power Adaptations. J Strength Cond Res, 2020. 34(1): p. 46-53.

(4) Ortega, J.A.F., Y.G.D.l. Reyes, and F.R.G. Pen˜a, Effects of strength training based on velocity versus traditional training on muscle mass, neuromuscular activation, and indicators of maximal power and strength in girls soccer players. Apunts Sports Med, 2020. 55(206): p. 53-61.

3 “One possible explanation is that the effects of the resistance training intervention on physical performance could be affected by several participants’ characteristics such as the initial training status or chorological age, while the other is the differences in resistance training variables such as the exercises, duration, periods, intensity and volume. Specifically, some studies adopted the fixed repetitions schemes to terminate the set in VBT group, whereas others used fixed velocity loss value either separately or in combination with the former.” → I would expect such explanations in the discussion section.

Response: We agree with it. We have deleted this section from the introduction.

Methods:

1 The representation of the search strategy is somewhat confusing. why, for example, was "endurance" searched for? A tabular representation might be easier to read and understand.

Response: We revised the searching strategy, and added a tabular (supplemental table 1) to detail the searching strategy and syntax. Thank you.

2 “Quality of evidence” Is this not (at least partially) redundant to the Pedro score?

Response: Actually, this part is following the latest PRISMA(2019) requirements. The Pedro score we used is to evaluate single included study, but GRADE is for evaluating the overall quality of all included studies. Thank you.

3 “Statistical analysis” → I would mention CHI^2 and I^2 only after the Random effects model has been described.

Response: We adjusted the order of related sentences in order to make it clear that we only used the random effect model to aggregate the effects. The reason for choosing random effect model is because fixed effect model is based on the assumption that the results apply only to a given group of studies, and assumes that variation in effect sizes among studies is due to within-study variance. Random-effects model apply more generally and assumes the true effects from different studies also differ from one another, representing a random sample of a population. Our study aim was to compare the training effect of VBT and PBT, and expect to apply the results more generally, not being limited in within-study variance.

4 The formula for SMD is wrong (or is displayed incorrectly).

Response: We think it is displayed incorrectly. The formula for SMD is [MDVBT– MDPBT/pooled SDpre].and we have also rewritten the description part to make it clearer. Thank you.

Results:

1 were the reference lists of the resulting 6 studies checked for potential additional studies?

Response: Yes, we checked it.

2 please avoid redundant information between text and tables/figures. Also there are some irrelevant information like (“The MD was calculated.”)

Response: Following a carefully check, we have already deleted some redundant information. Thank you.

3 “LVP with 60%1RM was chosen because 1m/s (60%1RM) was usually used to evaluate the performance in resistance training. “ → This sentence needs a reference.

Response: We have included 2 references for this statement. These are :Banyard, H.G., et al., Superior Changes in Jump, Sprint, and Change-of-Direction Performance but Not Maximal Strength Following 6 Weeks of Velocity-Based Training Compared With 1-Repetition-Maximum Percentage-Based Training. Int J Sports Physiol Perform, 2020: p. 1-11; Pareja-Blanco, F., et al., Effect of movement velocity during resistance training on neuromuscular performance. Int J Sports Med, 2014. 35(11): p. 916-24. We have added the references in the revised manuscript.

Discussion:

1 Recheck spelling & grammar

Response: We have done this in this version too. Thank you.

2 Table 3 is not necessary. In comparison to table 2, no additional information is provided here.

Response: this is also following the PRISMA’s requirements. Table 3 is to provide the detailed information.

3 The symmetry of the funnel plot could be additionally checked by egger's p Value.

Response: We have already added the egger’s test and the p value in the revised manuscript. Thank you.

10 Aug 2021

PONE-D-21-12316R1

Effects of Velocity Based Training vs. Traditional 1RM Percentage-based Training on Improving Strength, Jump, Linear and Change of Direction Speed Performance: A Systematic Review with Meta-analysis

PLOS ONE

Dear Dr. Li,

Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process.

Please submit your revised manuscript by Sep 24 2021 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file.

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If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter.

If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols. Additionally, PLOS ONE offers an option for publishing peer-reviewed Lab Protocol articles, which describe protocols hosted on protocols.io. Read more information on sharing protocols at https://plos.org/protocols?utm_medium=editorial-email&utm_source=authorletters&utm_campaign=protocols.

We look forward to receiving your revised manuscript.

Kind regards,

Daniel Boullosa

Academic Editor

PLOS ONE

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Comments to the Author

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Reviewer #2: (No Response)

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #2: I Don't Know

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #2: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #2: No

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6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #2: This is a valuable study on an interesting topic in the sports sciences field. However, there are some issues that I feel need to be addressed to bring the study up to publishable standards. Mainly, writing should be reviewed by a professional proofreader or a native-speaker, specially the Discussion section. Moreover, some changes are required throughout the this section in order to provide a deeper explanation of your findings. Number lines would help review process. Please see my specific comments below:

Abstract:

I would change “linear speed” to “linear sprint”. Linear speed is already performance. It would be like jump height. Therefore, it would be better to use: linear sprint throughout the manuscript.

Abstract. Methods. SD has not been previously defined

Abstract. Results. Why sometimes you show MD and others SMD? I would use only SMD. Please see my specific comments below.

Introduction

Third paragraph. These research to date… should read: these researches…

Therefore, A systematic review with… should read: Therefore, a systematic…

Methods

Search strategy.

syntax was shown in supplemental table 1… should read: syntax are shown…

Risk of bias assessment within individual studies

Two authors (The second… should read: the second

Brughelli et al [23]…should read: al.

Statistical analysis

Since MD can be highly influenced by sample characteristics. Would not it be better using always SMD?

SMD can amend some of the problems shown by MD, since it includes SD in the calculations.

Both algorithms of MD and SMD in speed and COD outcomes was adjusted…should read: were

Results

Search results

At last, 6 studies included in the qualitative…should read: were included

Risk of bias assessment

All of studies got high scores… should read: All studies or all the studies

Studies’ Characteristics

characteristics of 6 studies included in qualitative analysis was…should read: were

Among which, Only 1 study…should read: only

Quantitative analysis

load velocity with 40%1RM. Shouldn’t be 60% 1RM?

Discussion

IMHO, I miss you highlight the methodological differences between both approaches throughout the Discussion, especially in the Practical Applications section. Thus, you may help readers to better choose the proper method.

Strength performance

improvement in musclular strength…should read: muscular

similarities of biomechenics to a various…should read: biomechanics

PBT ( ES = 1.25) With the…should read: with

Please rewrite this sentence: This likely accounted for subtle decreases in load adjusted in accordence with targeted velocity

velocity testing device. although the…should read: device, although

…. and placebo effect from the velocity testing device. although the research conducted by

Chen et al. and Held et. al. did not provide the velocity data of training repetitions [20,

29], it could be inferred that participants might perform even higher repetition velocity

due to enhancing motivation and competitiveness from feedback of velocity[12]. Please split or rewrite this sentence

Furthermore, Interstingly,…should read: interestingly

and 48 hours in VBT was superior…should read: were

VBT should produced a better…should read: would produce

while it was likely for PBT to…should read: it is likely

With respect to the effects in faovr of VBT. This sentence should go on.

more repetition…should read: more repetitions

at maiximum intended velocity…should read: maximum

threshold type Ⅱ fiber which have a greater relative hypertrophy than type Ⅱ fiber…should be: type II and type I, respectively

for above metioned factors…should read: mentioned

device[44]. this finding…should read: This

Considering the methodology involved the use of post minus pre intervention value in our meta-analysis, it could. Please use comma when necessary

4.2 Jump performance

and muslce fiber type composition …should read: muscle

development [45] and muscle-tendo …should read: muscle-tendon

Furthermore, Banyard et al. reported that the mean deviation of

sessional repetition velocity was greater for the PBT (-13.6 ± 6.8%) contrasted to VBT

(-0.2 ± 5.2%) [22]. You should explain why these authors reported this and how can influence jump height adaptations.

is also evdence: evidence

intervetion exercise: intervention

resistance training [47], The higher movement… should read: the

Linear Speed and CODs performance

Evidence showed that the squat strength and sprint performance existed very large significant

correlation ( r= -0.77; p = 0.001) [48]. This sentence is hard to follow

above metioned: mentioned

may also impaire resistance: impair

in both group… should read: in both groups [18].

This negetive effects may: negative

This negligible results: these

still needed to distingush the difference: distinguish

CODs (ES = 0.67-0.79) favorited VBT compared to PBT [22]: favored

for this results: these

may be the same as above metioned such: mentioned

recovery. this implies that pactitioners are… shoud read: This implies that practitioners…

4.4 Limitations

all results was graded: were

Conclusion

less excaustive nature: exhaustive

TABLES

Table 2.

Song Chen 1995. I cannot access to this reference. But did they use as a reference load? the maximal power load? or all of them trained at the same velocity? It is strange that they compared PBT and VBT in 1997 when the first publications about using VBT instead of PBT are from 2010.

I guess they compared power-based training, but this is not the same idea, since the use power, not velocity, for monitoring and programing the training load.

Some of the abbreviations described in the footnote are not used in the table.

Table 3.

I miss some of the included studies here

FIGURES

Figure 3A. I guess this should be Song;, C. and M. qiwei, Effects of fixed velocity training methods on load

velocity profile. Journal of Beijing University of Physical Education, 1995. 18(3):

p. 81-88.

Figure 3D. how have you calculated the weight in Fig. 3D? It is weird that a study with 10 subjects means the 1.9% and other with 12 the 72.4% and the third one with 15 subjects and only the 25.7% of the total weight.

**********

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29 Sep 2021

Dear Professor Daniel Boullosa

Many thanks for your letter and the comments from the reviewers regarding our paper.

After carefully checking the manuscript, we have revised it according to the reviewer’s comments. We submit here the modified version as well as a list of change.

If you have any question, please let me know.

Thank you again.

Kind regards

Response to editor’s comments:

Thanks for your great comments on our paper. We have revised our paper according to your comments and make sure that the manuscript will be up to publishable level with your help.

Abstract:

1. I would change “linear speed” to “linear sprint”. Linear speed is already performance. It would be like jump height. Therefore, it would be better to use: linear sprint throughout the manuscript.

Response: We agree with your suggestions, and have already changed “linear speed” into “linear sprint” throughout the manuscript. Thank you.

2. Abstract. Methods. SD has not been previously defined.

Response: We have now defined SD. Thank you.

3. Abstract. Results. Why sometimes you show MD and others SMD? I would use only SMD. Please see my specific comments below.

Response: From a practical standpoint, we prefer MD in current study. This is because MD is simpler and more meaningful in practice. For example, if we tell the coaches that VBT can increase 1RM of squat by 10kg in 4 weeks, it will be easy to be understood. On the other side, if we tell them that 1RM can improve by 0.4 whole standard deviation it is very confusing. As a support, the American Psychological Association (APA) Task Force on statistical inference also suggests that if the units of measurement are meaningful on a practical level, then a MD is superior to a SMD. Thus, when all studies report the outcome using the same scale or the same tests, we used MD, otherwise we used SMD. that’s the reason why we sometimes show MD and others SMD. Thank you again.

Introduction

5. Third paragraph. These research to date… should read: these researches…

Response: We have corrected that. Thank you.

6. Therefore, A systematic review with… should read: Therefore, a systematic…

Response: We have corrected that too. Thank you.

Methods

Search strategy.

7. syntax was shown in supplemental table 1… should read: syntax are shown…

Response: This has been corrected.

8. Risk of bias assessment within individual studies

Two authors (The second… should read: the second

Response: We have corrected that. Thank you.

9. Brughelli et al [23]…should read: al.

Response: This has been corrected. Thank you.

Statistical analysis

10.Since MD can be highly influenced by sample characteristics. Would not it be better using always SMD? SMD can amend some of the problems shown by MD, since it includes SD in the calculations.

Response: Thank you for your comment. Previously (response to comment 3) we have justified our approach. Thank you.

11. Both algorithms of MD and SMD in speed and COD outcomes was adjusted…should read: were

Response: This has been corrected. Thank you.

Results

Search results

12. At last, 6 studies included in the qualitative…should read: were included

Response: This has been corrected. Thank you.

Risk of bias assessment

13. All of studies got high scores… should read: All studies or all the studies

Response: This has been corrected. Thank you.

Studies’ Characteristics

14. characteristics of 6 studies included in qualitative analysis was…should read: were

Response: This has been corrected. Thank you.

15. Among which, Only 1 study…should read: only

Response: This has been corrected. Thank you.

Quantitative analysis.

16. load velocity with 40%1RM. Shouldn’t be 60% 1RM?

Response: Thank you for this comment too. We have corrected that.

Discussion

17. IMHO, I miss you highlight the methodological differences between both approaches throughout the Discussion, especially in the Practical Applications section. Thus, you may help readers to better choose the proper method.

Response: We have added the methodological differences between VBT and PBT in the discussion and practical applications section following your suggestions. Thank you .

Strength performance

18. improvement in musclular strength…should read: muscular

Response: This has been corrected. Thank you.

19. similarities of biomechenics to a various…should read: biomechanics

Response: We corrected that. Thank you.

20. PBT ( ES = 1.25) With the…should read: with

Response: This has been corrected. Thank you.

21. Please rewrite this sentence: This likely accounted for subtle decreases in load adjusted in accordance with targeted velocity.

Response: We have rewritten this sentence. Thank you.

22. velocity testing device. although the…should read: device, although

Response: We corrected that too. Thank you.

23. …. and placebo effect from the velocity testing device. although the research conducted by Chen et al. and Held et. al. did not provide the velocity data of training repetitions [20,29], it could be inferred that participants might perform even higher repetition velocity due to enhancing motivation and competitiveness from feedback of velocity[12]. Please split or rewrite this sentence.

Response: We have rewritten this sentences.

24. Furthermore, Interestingly,…should read: interestingly

Response: We have corrected that. Thank you.

25. and 48 hours in VBT was superior…should read: were

Response: This has been corrected. Thank you.

26. VBT should produced a better…should read: would produce

Response: This has been corrected. Thank you.

27. while it was likely for PBT to…should read: it is likely

Response: This has been corrected. Thank you.

28. With respect to the effects in favor of VBT. This sentence should go on.

Response: After considerable thinking, we decided to delete this incompletely sentence.

29. more repetition…should read: more repetitions

Response: This has been corrected. Thank you.

30. at maiximum intended velocity…should read: maximum

Response: This has been corrected. Thank you.

31. threshold type Ⅱ fiber which have a greater relative hypertrophy than type Ⅱ fiber…should be: type II and type I, respectively

Response: This has been corrected. Thank you.

32. for above metioned factors…should read: mentioned

Response: This has been corrected. Thank you.

33. device[44]. this finding…should read: This

Response: This has been corrected. Thank you.

34. Considering the methodology involved the use of post minus pre intervention value in our meta-analysis, it could. Please use comma when necessary

Response: We have used comma. Thank you.

4.2 Jump performance

35. and muslce fiber type composition …should read: muscle

Response: This has been corrected. Thank you.

36. development [45] and muscle-tendo …should read: muscle-tendon.

Response: This has been corrected. Thank you.

37. Furthermore, Banyard et al. reported that the mean deviation of

sessional repetition velocity was greater for the PBT (-13.6 ± 6.8%) contrasted to VBT(-0.2 ± 5.2%) [22]. You should explain why these authors reported this and how can influence jump height adaptations.

Response: We added a sentence to explain that. Thank you for your comment.

38. is also evdence: evidence

Response: This has been corrected. Thank you.

39. intervetion exercise: intervention

Response: This has been corrected. Thank you.

40. resistance training [47], The higher movement… should read: the

Response: This has been corrected. Thank you.

Linear Speed and CODs performance

41. Evidence showed that the squat strength and sprint performance existed very large significant correlation ( r= -0.77; p = 0.001) [48]. This sentence is hard to follow.

Response: We have rewritten this sentence. Thank you.

42. above metioned: mentioned.

Response: This has been corrected. Thank you.

43. may also impaire resistance: impair.

Response: This has been corrected. Thank you.

44. in both group… should read: in both groups [18].

Response: This has been corrected. Thank you.

45. This negetive effects may: negative.

Response: This has been corrected. Thank you.

46. This negligible results: these.

Response: This has been corrected. Thank you.

47. still needed to distingush the difference: distinguish.

Response: This has been corrected. Thank you.

48. CODs (ES = 0.67-0.79) favorited VBT compared to PBT [22]: favored.

Response: This has been corrected. Thank you

49. for this results: these

Response: This has been corrected. Thank you.

50. may be the same as above metioned such: mentioned

Response: This has been corrected. Thank you.

51. recovery. this implies that pactitioners are… shoud read: This implies that practitioners…

Response: We corrected that too. Thank you.

4.4 Limitations

52. all results was graded: were

Response: We corrected that. Thank you.

Conclusion

53. less excaustive nature: exhaustive

Response: This has been corrected. Thank you.

TABLES

Table 2.

54. Song Chen 1995. I cannot access to this reference. But did they use as a reference load? the maximal power load? or all of them trained at the same velocity? It is strange that they compared PBT and VBT in 1997 when the first publications about using VBT instead of PBT are from 2010.

I guess they compared power-based training, but this is not the same idea, since the use power, not velocity, for monitoring and programing the training load.

Response: After carefully rechecking this reference we have made sure that this study by Song Chen 1995 trained the VBT group at the same velocity by adjusting the load with a self-made velocity testing devices, which is in accordance with our definition of VBT described in the method. As you correctly mentioned, Chen’s concept was associated with power-based training at that time. However, the author puts forward some quite new and unique insight on velocity load such as the range of speed control (velocity loss), increasing the speed with controlled weight, and increasing weight with controlled speed. This same author also published several articles from his doctoral thesis to state the concept of velocity load training and provided suggestions on how to prescribe the load using velocity. Please find below one of his articles’ abstract published in 1994. The full reference for that is Song Chen, Qiwei Ma. Training theory and method of developing velocity-force by quantitative control of movement speed. Journal of Beijing University of Physical Education. 1994; 17(2):78-89.

55. Some of the abbreviations described in the footnote are not used in the table.

Response: Thank you for this suggestion too. After checking we have deleted the extra abbreviations.

Table 3.

56. I miss some of the included studies here

Response: You are right, two studies were not in the table 3. Because table 3 is to show the results of dealing with the multiplicity in included studies. Therefore, we did not include the study without multiplicity in table 3. Thank you.

FIGURES

57. Figure 3A. I guess this should be Song;, C. and M. qiwei, Effects of fixed velocity training methods on load velocity profile. Journal of Beijing University of Physical Education, 1995. 18(3):p. 81-88.

Response: Yes, that’s Song Chen and Qiwei MA. We have corrected it in the figure. Thank you.

58. Figure 3D. how have you calculated the weight in Fig. 3D? It is weird that a study with 10 subjects means the 1.9% and other with 12 the 72.4% and the third one with 15 subjects and only the 25.7% of the total weight.

Response: Thank you for this point too. This is because we adopted the random-effects model to calculate the MD in figure 3D via Revman software. Weighting within the random-effects model assumes two sources of variability in effects, one from sampling error and one from study level differences. However the latter is based on the variability in effect sizes across the group of studies and it has been taken to imply that the random-effects model assumes a distribution of true population effects from which the observed studies are sampled. The reason for this large difference in weight distribution may be due to the fact the third one with much bigger SD than the other two studies results in large study level difference.

Submitted filename: Response to Reviewers-0815.docx

Click here for additional data file.

27 Oct 2021

Effects of Velocity Based Training vs. Traditional 1RM Percentage-based Training on Improving Strength, Jump, Linear Sprint and Change of Direction Speed Performance: A Systematic Review with Meta-analysis

PONE-D-21-12316R2

Dear Dr. Li,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Daniel Boullosa

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

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Reviewer #2: All comments have been addressed

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The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #2: Yes

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Reviewer #2: Yes

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Reviewer #2: Yes

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PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

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Reviewer #2: No

5 Nov 2021

PONE-D-21-12316R2

Effects of Velocity Based Training vs. Traditional 1RM Percentage-based Training on Improving Strength, Jump, Linear Sprint and Change of Direction Speed Performance: A Systematic Review with Meta-analysis

Dear Dr. Li:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

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on behalf of

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