Does the type of foam roller influence the recovery rate, thermal response and DOMS prevention?

PURPOSE: Supporting post-exercise recovery requires choosing not only the right treatment but also the equipment, in which the impact is not always clear. The study aimed to determine the effect of foam rolling on the rate of lactate removal and DOMS prevention and whether the type of foam roller is effective in the context of post-exercise recovery.
METHODS: This randomized trial enrolled 33 active healthy males divided into three groups of eleven individuals: foam rolling with a smooth (STH) or grid roller (GRID) or passive recovery (PAS). All the participants performed full squat jumps for one minute. Examination took place at rest (thermal imaging of skin temperature-[Tsk] and blood lactate-[LA]), immediately following exercise (Tsk & LA), immediately after recovery treatment (Tsk) and after 30 minutes of rest (Tsk & LA). Their pain levels were assessed using the Visual Analog Scale (VAS) 24, 48, 72, and 96 hours after exercise.
RESULTS: The magnitude of lactate decrease depended on the type of recovery used. In the PAS group, the decrease in lactate concentration by 2.65 mmol/L following a half-hour rest was significantly lower than that in the other groups (STH vs. PAS p = 0.042 / GRID vs. PAS p = 0.025). For thermal responses, significant differences between both experimental groups were noted only 30 minutes after exercise. A significant decrease in pain in the STH group occurred between 48 and 96 hours, while the GRID group showed a systematic significant decrease in VAS values in subsequent measurements. Changes in VAS values in subsequent measurements in the PAS group were not statistically significant (p>0.05).
CONCLUSIONS: Foam rolling seems to be effective for enhancing lactate clearance and counteracting DOMS, but the type of foam roller does not seem to influence the recovery rate.

RCT Entities:   Population Interventions Outcomes

Introduction

During intense exercise, human muscles produce and release large quantities of lactate (LA) while at the same time using it as a potential source of energy for further work [1]. Therefore, since the development and onset of fatigue correlate well with blood lactate (LA) accumulation, lactic acid measurement provides an effective and accessible measure that can contribute to fatigue [2]. Moreover, most effective methods of lactate clearance during recovery and their impact on performance have attracted the attention of sports scientists and practitioners. Despite many post-exercise recovery treatments, only a few are considered effective. Some examples of the methods used for improving recovery include stretching, massage, ice massage and cold water immersion, transcutaneous muscle stimulation, kinesiotaping, music therapy, low-intensity exercise, and recovery using pharmacological agents [3, 4, 5]. Most of them are based on improving blood flow, which can be done by different methods of stimulation (e.g., temperature, mechanical impact, muscle movements).

Increasing blood flow through muscles following exercise can help quickly eliminate fatigue symptoms. Therefore, low-intensity exercise can have a positive effect on post-exercise muscle recovery [6]. Recovery can also be supported by mechanically increasing the compression on tissues to induce vasodilation and increase blood circulation [4]. One of the methods of achieving this is self-myofascial release (SMFR) by means of a foam roller, which can increase the hydration and elasticity of fascia. Foam rolling involves using the pressure of a person’s own body weight on a foam roller and therefore on soft tissue during movement [7].

The effect of increased arterial blood flow may induce the physiological mechanisms preventing muscle fatigue associated with physical exercise. Foam rolling treatment is associated with improved arterial perfusion by increasing blood flow in the arteries, so it seems that foam rolling (FR) may lead to physiological adaptive changes in increased efficiency, ROM and recovery [8, 9, 10]. Studies in the field of SMFR indicate the effectiveness of this technique in relieving pain due to many physiological responses. Some of them are increased blood flow, reduced arterial stiffness, improved vascular endothelial function and increased nitric oxide concentration [11].

Research also suggests that the sensation of DOMS (delayed onset muscle soreness) may be weaker when using the foam rolling technique due to thixotropy, which could cause locally altered tissue stiffness or nonneural tone [12]. Such an approach promotes the gel-like state of fascia without any impairment of neuromuscular properties [13]. In a study by Bradbury-Squires et al. [14], these symptoms were significantly reduced in each subsequent test (24 h, 48 h and 72 h) in persons who performed FR once a day with two sets of 60 seconds each. Delayed onset muscle soreness is primarily caused by changes in connective tissues, and foam rolling affects mainly connective tissue and not muscle tissue. This explains the reduction in pain sensation without a visible loss of muscle function [15]. Another underlying cause is the increase in blood flow, which leads to the removal of blood lactic acid, reduction in swelling and oxygen supply to the muscles [9].

D'Amico and Paolone [16] studied the effect of rolling on the recovery between two anaerobic efforts and found that FR may not be an effective way to support recovery between intensive exercises with a 30-minute rest. According to the authors, foam rolling during recovery after exercise-induced muscle damage caused by sprinting does not seem to be effective for reducing muscle pain beyond what can be achieved with a dynamic warm-up. Hodgson et al. [17] also questioned the long-term effects of foam rolling on pain sensation as immediate effects of foam rolling may not translate into chronic changes probably due to central pain modulation which might require longer SMFR influence.

The factor potentially affecting the effectiveness of the SMFR procedure is the type of foam roller used for exercises. Greater hardness and a nonuniform structure (grid) contribute to increasing the point pressure on the massaged tissue so that the analgesic effect may be greater [18, 19]. In addition to increased blood circulation, SMFR is associated with trigger-point release, which, with the use of grid foam rollers, might increase pressure on tissue and enhance recovery [20].

Safe, noninvasive diagnostic methods are needed to ensure proper training processes and health care in athletes. An example of such methods is thermal imaging. Information about the efficiency of metabolic changes and endogenous heat removal systems during training associated with the return to homeostasis and post-exercise recovery is indicated by the change in body surface temperature. Thermal imaging techniques offer opportunities for monitoring these phenomena. The findings published by Adamczyk et al. [21] showed that maximum anaerobic exercise was accompanied by a significant decline in temperature on the surface of the involved muscles, whereas the degree of reduction was proportional to the blood lactate concentration. Lactic acid levels effectively reflect muscle fatigue during and after exercise [1]. Lactate measurement can be performed immediately following or even during exercise because it does not require complex laboratory procedures [22]. Thermal imaging allows for a psychologically comfortable evaluation of post-exercise recovery without substantial financial outlays [23].

Heterogeneity in research makes difficult to identify a consensus on an optimal SMFR program and the optimal use of FR [7]. Several important issues related to foam rolling, such as optimal duration [24], foam roller density and tissue pressure [25], remain unexplained. Differences in the force acting on muscles during foam rolling caused by body weight and individual differences in techniques can lead to different effects of foam rolling [26]. Taking this into account, the aim of the study was to determine whether the type of roller in single foam rolling treatment influences the rate of lactate removal and DOMS prevention.

Materials and methods

Participants

The randomized trial enrolled 33 active healthy untrained male participants randomly divided into three groups (Table 1) of eleven people depending on the type of recovery: rolling with a smooth (STH) or grid (GRID) foam roller or passive recovery (PAS). Their mean age was 24.5 years (±2.9), mean body height was 182.0 cm (±5.7), and mean body mass was 82.7 kg (±9.4). All participants had a normal body mass index (BMI). The study was conducted in October 2019. Each group performed test separately but experimental sessions for groups, were held at the same time of the day. Participants were informed about the risks and provided their written informed consent. The study was approved by the Research Ethics Committee of the Józef Piłsudski University of Physical Education in Warsaw (No. SKE 01-41/2016).

Table 1

Biometric characteristics of the participants divided into groups, mean values (±SD).

Group	SMOOTH ROLLER (STH) n = 11	GRID ROLLER (GRID) n = 11	PASSIVE REST (PAS) n = 11
Age [years]	24.4 ±3.4	24.5 ±2.9	24.1 ±4.4
Body height [cm]	182.8 ±5.3	182.0 ±5.7	181.5 ±6.6
Body mass [kg]	82.3 ±5.4	82.7 ±9.4	83.2 ±7.2

Experimental approach to the problem

Before the experiment, the participants were rest subjected to 20 minutes of thermal adaptation to the conditions of the room where the examinations were performed. The purpose of the adaptation was to achieve a state of thermal balance in relation to the ambient temperature so that the obtained thermograms were reliable. Therefore, changes in the thermal images were the result of disturbances in production or heat dissipation as a result of the exercises [27]. Resting blood lactate levels from a capillary earlobe sample were measured and analyzed with a Dr. Lange LP 420 photometer (Germany) [28]. After the adaptation, a thermal image of the lower limbs was taken. Due to adaptation before thermal imaging, all participants wore shorts to expose as much of the lower limbs as possible.

After the completion of adaptation and thermal images at rest conditions (REST), the participants performed the exercise test described in our previous studies [21, 29]. The test consisted of maximum-effort squat jumps performed for one minute. The test was developed to be performed in a short time with limited space and allowed for inducing a significant increase in blood lactate levels as an effect of the glycolytic nature of exercise [21, 29]. During our preliminary research, creatine kinase (CK) activity was also measured 24 hours following the same exercise. The average CK values ranged between 300 and 500 U-L-1, which strongly suggests high-intensity exercise and the possible occurrence of DOMS [30].

Immediately after the trial (IAT), the second round of thermal imaging and blood lactate measurement was carried out. Next, the lower limbs were foam rolled in the STH and GRID groups. A portion of the respondents used smooth foam rollers of medium density, size 30 cm x 15 cm, while the other group performed rolling using grid foam rollers of medium density with the same size. The participants performed a cycle of 30 complete movements with a frequency of 50 beats per minute [18]. Bodyweight was used for each muscle group, starting with the gastrocnemius muscle, followed by the hamstring muscles, quadriceps muscle, adductor group, iliotibial band and gluteus muscle. Both lower limbs were subjected to this procedure. The PAS group was instructed to rest passively.

After foam rolling treatment (ART), each participant had a thermal image taken and then rested until 30 minutes (AFTER30) from the completion of the exercise. Again, a thermal image was taken, and blood lactate measurement was performed. Furthermore, 24, 48, 72 and 96 hours after the completion of the activity, the participants were asked to assess their lower extremities pain sensation by completing the VAS (Visual Analog Scale) from 0 to 10, in which 0 indicated ‘‘no pain” and 10 represented ‘‘extreme pain” [31, 32]. Only subjects who declared no pain symptoms, both in terms of the lower limbs and general body pain, before the examination were included in the study.

Thermograms of the front and back surfaces of the lower limbs for each participant were taken in a standing position to determine skin temperature (Tsk). The analyzed area was divided into the following regions of interest (ROIs): anterior thigh (from the deflection in the hip joint to the knee—excluding the patella), anterior calf (from the tibial tuberosity to the ankle), posterior thigh (from the gluteal folds to the knee—excluding the popliteal fossa) and posterior calf (from the bottom of the popliteal fossa to the ankle). A thermal imaging camera (FLIR A325, FLIR Systems, Sweden) was used for all infrared (IR) measurements. The camera had a measurement range from -20 to +350°C, an accuracy of ±2°C or ±2%, a sensitivity below 0.05°C, an infrared spectral band of 7.5–13 μm, a refresh rate of 60 Hz, and a resolution of 320–240 pixels of FPA. The distance between the camera and the photographed object was set at 2.5 m. Recommendations for thermal imaging in sports and exercise medicine were followed as described in previous research [33]. The analysis was performed with the use of Researcher 2.9 Pro software designed for use with the thermal camera.

Statistical analysis

For the sample size (3 groups, each n = 11), assuming a typical significance level alpha = 0.05 (two-way test) and the standardized effect RMSSE = 0.77, the test power was 0.88. The assumption of compliance of the distributions of the variables with the normal distribution was tested using the Shapiro-Wilk test. The assumption of the equality of variance in groups was evaluated using Levene's test. In the repeated measures procedure, the assumption of sphericity of variance was also verified (Mauchley test). To determine the significance of differences in values (LA, VAS, Tsk) in subsequent measurements, we used ANOVA with repeated measures (Bonferroni post hoc test). ANOVA for factorial designs (Bonferroni post hoc test) was used to determine the differences in values between each condition (STH, GRID and PAS). Effect size measures used the eta-squared (η2) statistics: small effect, <0.10; medium effect, 0.10–0.40; and large effect, >0.40 [34]. The relationships between the magnitude of lactate decline, VAS indications and lower limb temperature were analyzed using the Pearson correlation coefficient. The level of p<0.05 was set in all analyses to assess the significance of the effects. All the statistical analyses were performed using STATISTICA software (v. 13, Stat. Soft. USA).

Results

Lactate

No significant differences between the groups were found in any of the measurements. The resting lactate (LA) level and the changes following the exercise test and recovery were similar in all groups (Fig 1) (F(4,60) = 1.61; p = 0.18; η2 = 0.10). Immediately after the trial (IAT), a significant (F(1,32) = 293.9; p<0.001; η2 = 0.90) increase in the blood lactate level was observed, which demonstrates the glycolytic anaerobic nature of exercise. Thirty minutes of recovery was enough to significantly reduce blood lactate levels (F(1,32) = 92.9; p<0.001; η2 = 0.74), however LA levels remained higher than at the resting state. The magnitude of lactate decline depended on the form of recovery used (F(2,30) = 3.38; p = 0.04; η2 = 0.18). The highest decrease in lactate (Δ 4.94 mmol/L) was observed in the GRID group. However, this difference was not significant (p = 0.82) compared to the STH group (Δ 4.25 mmol/L). The decrease in lactate concentration by 2.65 mmol/L following a half-hour rest was significantly lower than that in the other groups (STH vs. PAS p = 0.042 / GRID vs. PAS p = 0.025).

Fig 1

Changes in blood lactate levels, mean values (95% CI).

Temperature changes

As expected, exercise caused a significant drop in skin temperature (Tsk) in most of the regions of interest (ROIs). Evaluation of the acute effect of foam rolling on skin temperature revealed no significant changes between the 2nd and 3rd measurements (p>0.05). The greatest diversity in thermal responses was observed for the 4th measurement. In the STH group, the gradually increasing temperature reached the resting state level. At the same time, the GRID group had a significantly higher Tsk in the anterior thigh, while the posterior thigh reached a temperature close to the resting state level (Table 2).

Table 2

Mean values [°C] of the anterior and posterior skin surface temperature of ROIs in consecutive measurements.

		Measurement 1 Resting state (REST)		Measurement 2 Immediately After Trial (IAT)		Measurement 3 After foam rolling treatment (ART)		Measurement 4 30th minute of recovery (AFTER30)
		Mean±SD	CI 95%	Mean±SD	CI 95%	Mean±SD	CI 95%	Mean±SD	CI 95%
Smooth	Anterior thigh	29.95±1.12 *(2)	29.20–30.7	28.7±0.90 ***(4) *(1)	28.09–29.3	29.19±1.55 *(4)	28.15–30.24	30.48±1.44 ***(2) *(3)	29.51–31.45
	Posterior thigh	30.02±1.59 **(3) *(2)	28.96–31.09	28.87±0.98 *(1,4)	28.21–29.53	28.37±1.56 ***(4) **(1)	27.33–29.42	30.16±1.02 ***(3) *(2)	29.47–30.84
	Anterior calf	29.68±1.31 ***(2) **(3)	28.8–30.56	28.17±1.52 ***(1,4)	27.15–29.19	28.31±0.88 **(1.4)	27.72–28.9	29.66±0.92 ***(2) **(3)	29.04–30.28
	Posterior calf	29.98±1.24 **(2,3)	29.15–30.81	28.54±1.37 **(1,4)	27.61–29.46	28.6±0.70 **(1,4)	28.12–29.07	29.92±0.65 **(2,3)	29.48–30.36
Grid	Anterior thigh	29.36±1.93 **(4)	28.07–30.65	28.43±1.56 ***(4)	27.39–29.48	28.78±1.60 ***(4)	27.71–29.86	30.51±1.33 ***(2,3) *(1)	29.62–31.4
	Posterior thigh	29.83±2.35 *(3)	28.25–31.41	28.49±1.66	27.38–29.61	28.32±1.47 *(1)	27.33–29.31	29.77±1.66	28.66–30.89
	Anterior calf	29.63±1.48 ***(3) *(2)	28.63–30.62	28.65±1.30 *(1)	27.78–29.52	28.15±1.43 ***(1) **(4)	27.19–29.11	29.29±1.00 **(3)	28.62–29.96
	Posterior calf	30.15±1.14 ***(2,3)	29.39–30.92	28.67±1.08 ***(1)	27.95–29.4	28.16±1.11 ***(1) **(4)	27.42–28.91	29.49±1.26 **(3)	28.65–30.34
Passive	Anterior thigh	28.76±0.31 **(2)	28.55–28.96	27.8±0.78 ***(4) **(1)	27.27–28.32	28.34±0.93 **(4)	27.71–28.96	29.27±0.63 ***(2) **(3)	28.84–29.69
	Posterior thigh	28.76±0.44 **(2,4)	28.46–29.05	27.86±0.66 ***(4) **(1)	27.42–28.31	28.3±0.91 ***(4)	27.69–28.91	29.62±0.66 ***(2,3)**(1)	29.18–30.06
	Anterior calf	28.65±1.28 *(3)	27.78–29.51	27.76±0.90	27.16–28.37	27.57±1.04 *(1,4)	26.87–28.26	28.55±0.70 *(3)	28.08–29.02
	Posterior calf	28.95±0.59 ***(2,3)	28.56–29.34	27.78±0.78 ***(1) *(4)	27.25–28.3	27.54±0.89 ***(1) **(4)	26.95–28.14	28.51±0.51 **(3) *(2)	28.16–28.85

* p<0.05

** p<0.01

***p<0.001 significant difference vs REST (1) / IAT (2) / ART (3) / AFTER30 (4)

After initial acclimation, the temperatures of the lower limbs in all groups were similar to each other. The only significant difference was noticed for the posterior calf (F(2,30) = 4.4; p = 0.02; η2 = 0.23) between the PAS and GRID groups (p = 0.03). No relevant differences were found in the second measurement. Furthermore, in one ROI (posterior calf), a difference occurred after foam rolling (F(2,30) = 3.7; p = 0.04; η2 = 0.20), but this was between the PAS and STH groups (p = 0.03). The largest difference between groups was observed after 30 minutes of recovery. The only ROI with no significant differences between groups was the posterior thigh. Relevant changes were observed (F(2,30) = 3.91; p = 0.03; η2 = 0.21) between the PAS and GRID groups (p = 0.049) for the anterior thigh. Furthermore, in the anterior calf, significant differences (F(2,30) = 4.51; p = 0.02; η2 = 0.23) were found for the STH and PAS groups (p = 0.02). In the posterior calf, temperatures differentiated (F(2,30) = 7.58; p = 0.002; η2 = 0.24) the PAS group from both the STH (p = 0.002) and GRID (p = 0.04) groups. No significant correlations between the lower limb temperature and both the LA level and ΔLA were found in the thirtieth minute, regardless of the group (p>0.05).

Visual Analog Scale

Pain was significantly reduced in all groups 96 hours after completing exercise. The evaluation of pain sensation between 24 and 72 hours after the completion of exercise did not reveal any significant differences between the groups. Due to the type of support of the post-exercise recovery, significantly lower VAS values were observed only 96 hours after the study (Fig 2). Analysis of the decreased pain sensation in the STH group showed significant changes between 48 and 72 hours (p = 0.018) and 72 and 96 hours (p = 0.020). A gradual significant decrease in VAS was found in the GRID group in subsequent measurements (24/48 h p = 0.037; 48/72 h p = 0.023; 72/96 h p = 0.001). Changes in VAS in subsequent measurements in the PAS group were not statistically significant (p>0.05). No statistically significant correlations were demonstrated between the degree of lactate decrease and the indications of VAS (p>0.05) and Tsk (p>0.05).

Fig 2

VAS values for the individual groups examined in subsequent measurements, mean values (95% CI).

Discussion

The aim of this study was to determine the effect of foam rolling on the rate of lactate removal and DOMS prevention and whether the type of foam roller was effective in the context of post-exercise recovery. The findings suggest that using a foam roller as a self-myofascial release technique is an effective approach in supporting post-exercise lactate removal, but does not prevent the pain associated with damaged muscle fibers (DOMS). Furthermore, the type of foam roller does not seem to increase the recovery rate.

Blood lactate changes

The participants were subjected to maximum anaerobic exercise. However, no significant differences were found in the magnitude of the decrease in LA 30 minutes after the exercise, but both groups using the methods supporting recovery had a higher decrease in lactate than the group that rested passively. This is consistent with research on the predominance of active forms of recovery over passive ones. Some authors suggest that with the use of active methods to support recovery, blood flow in muscles is improved and lactate is removed more quickly [6]. Studies have shown that foam rolling also affects the cardiovascular system, reduces arterial stiffness, improves vascular endothelial function and increases blood flow [11, 35].

To the best of our knowledge, no unequivocal results of research on the effect of foam rolling on blood lactate levels after intense exercise have been published to date. Shalfawi et al. found that using foam rolling as a self-myofascial release technique during recovery did not increase the rate of blood lactate clearance in the cycling test to exhaustion followed by a Wingate performance test [36]. Moreover, Moraska et al. [37] stated that single trigger point release massage affected anaerobic metabolism. Our research did not support this theory, and the difference may be due to the size of the massaged muscle surface as well as the higher tolerance to high-intensity exercise and the recovery capacity of subjects.

The use of foam rolling is a form of self-massage through mechanical pressure on tissues. The potential benefits and mechanisms of massage are similar to foam rolling, including increased blood circulation and venous return, greater lactate clearance and decreased pain sensation [38, 39]. The results of this form of supportive recovery are also inconclusive. Some studies failed to show any effect of massage on improving lactate clearance. Bielik [40] observed that massage did not reduce the blood lactate concentration after intensive physical activity and that active methods (associated with low-intensity muscle work) of recovery were more effective in reducing lactate levels. A possible explanation was presented by Hinds et al. [41], who demonstrated that massage increased skin blood flow but without an increase in arterial blood flow, which seems to be crucial for lactate clearance. On the other hand, Özsu et al. [42] showed better quality of recovery after using the self-myofascial release technique. Furthermore, the findings published by Adamczyk et al. [29] showed a significantly higher decrease in lactic acid after ice massage compared to the control group. A potential explanation may be that in contrast to massage, foam rolling requires low-intensity muscle activity. Therefore, seems that active methods to support recovery are more effective than massage in removing LA following exercise, while massage is more effective than passive rest [43]. Another explanation might be the set frequency of treatment, as self-regulated intensities showed enhanced lactate clearance [44].

Thermal imaging was carried out to assess changes in temperature, which is closely related to the recovery and evaluation of DOMS following intensive exercise [45]. Thermography has been reported in the literature as an effective technique to diagnose post-exercise pain [21, 29, 45], especially during the first 24 hours after physical activity. Furthermore, Adamczyk et al. [21] documented correlations between the decrease in body surface temperature in working muscles after maximum anaerobic exercise and the degree of decrease in blood lactate levels.

As mentioned above [21], the study did not show any significant differences in blood lactate levels, but the magnitude of lactate decline 30 minutes following exercise was different. Skin temperature (Tsk) showed significant differentiation. The test results showed a significant decrease in the surface temperature of the lower limbs of approximately 1.2–1.5°C immediately after exercise (Table 2), which is in line with previous results [21, 29]. Reduced skin surface temperature is a typical thermoregulatory response to exercise due to redirected blood flow. These changes depend on exercise, and the more intensive the physical activity is, the greater the changes in body surface temperature [29]. It is important to note that there were absolutely no significant changes in skin temperature between immediately after exercise and after foam rolling treatment (28.31°C and 28.30°C, respectively). This contradicts the findings on the influence of massage on thermal response, where skin temperature was elevated after the application of massage [41]. The activation of recovery processes was confirmed by at least a 1°C (Table 2) temperature increase after 30 minutes from the completion of exercise in each group. This occurs as a result of the return of peripheral blood to the circulation typical of resting conditions and the increased activation of involved muscles that release more energy after being exercised [21]. This strongly suggests a delayed effect of foam rolling for enhancing recovery throughout the redirection of blood flow to recovering muscles; in particular, the cutaneous vascular response to intensive effort consists of temporarily reducing blood flow in the skin, narrowing the vessels, and dilating the blood vessels to remove excess heat [46]. Al-Nakhli et al. [45] also found that increased skin temperature following exercise may result from increased blood flow in muscles due to inflammation and recovery of damaged tissues. The analysis of temperature changes reveals that they are more varied on the shin surface, most likely due to lower muscle mass and thus increased pressure.

Murray et al. [47] studied the effect of foam rolling on muscle temperature and flexibility, but contrary to the above results, they did not find any significant temperature change. Significant differences between both experimental groups were documented only 30 minutes after exercise. This may demonstrate an increased metabolic activity caused by foam rolling, which seems to be conducive to recovery. This theory is supported by both the observed higher values of ΔTsk and ΔVAS in groups using foam rolling techniques. The potentially divergent results may have been caused by the different types of foam rollers used as the pressure force, and the stimulus penetration depth of myofascial release is different [25]. Additionally, it is difficult to determine the exact pressure and duration required for each muscle during foam rolling, as the thermal response of the muscles depends on the applied pressure during treatment [48].

No differentiation in thermal response due to the type of foam roller was demonstrated. During foam rolling, the trigger point may escape from the roller’s pressure, which may reduce the effectiveness of the therapy and increase the tension response of the athlete by pressing the trigger point as a result of the response to blood flow restriction in the trigger point area. This reaction restores normal blood and lymph circulation. At the same time, the process of removal of metabolites within the compressed tissue can be intensified. This improves circulation and reduces tissue adhesion [49, 50]. The effectiveness of this method was confirmed for foam rolling, but the type of foam roller was not important.

DOMS

The values of VAS observed in our study showed a typical timeline of pain sensations [51]. Pain complaints rated throughout the VAS are expected to peak between 24 and 48 hours post-exercise [32], but it must be noted that the VAS and pressure pain threshold are associated with the different ways to quantify pain sensation. However, grid foam rollers are able to apply significantly higher pressure on the soft tissue than smooth rollers during treatment [25], and the positive effect of foam rolling on pain sensation was revealed only 96 hours after exercise. Possible that differences should be revealed earlier, but the analysis of VAS changes over time (ΔVAS) suggests the effectiveness of foam rolling compared to passive rest. This result is partly reflected in the analysis of the literature. Beier et al. [52] observed that FR does not produce measurable benefits in terms of the sensation of fatigue after 24 hours. On the other hand, Drinkwater et al. [53] emphasized that foam rolling appears to improve performance in the later stages of recovery following eccentric exercise, which might explain the positive effects observed after 96 hours. Foam rolling was also beneficial for minimizing muscle soreness in research by McDonald et al. [54]. In light of research, compression of the tissues located above a cylindrical roller increases the range of motion (ROM) while maintaining power and strength [55] and brings relief by relaxing muscle tension and restoring muscle flexibility [56]. Furthermore, D'Amico and Paolone [16] observed the best effects of recovery in a group using FR compared to those who rested passively. Analysis of the VAS in the study revealed a better mood in people who performed rolling with both smooth and grid foam rollers, but there were no differences in the speed or quality of recovery due to the type of foam roller. This would undermine a fairly common theory [18] of deeper tissue penetration achieved by means of grid foam rollers.

According to our study, the effectiveness of foam rolling treatment for enhancing post-exercise recovery has been confirmed, but we found no effect of foam roller type on the recovery quality. However, there are some limitations of this analysis. First, our study included rather small groups, which might have resulted in reduced statistical power of the provided analysis. Second, exercise was limited to a single foam rolling procedure, so the influence of treatment time, frequency and roller density still remains unclear. Consequently, there may be some differences in the pressure exerted on muscle tissue through FR. These discrepancies may explain some of the inconsistent findings within the current literature, and future research should focus on finding an optimal foam rolling program.

Conclusions

The study results confirm the effectiveness of foam rolling in the support of recovery. Foam rolling might be implemented after workouts to enhance recovery between training sessions [57]. There is also evidence of a favorable circulatory response after foam rolling, a reduction in arterial stiffness, an improvement in vascular endothelial function and an increase in arterial blood flow [37]. The use of foam rolling after training might be effective in some cases (e.g., to increase sprinting performance and flexibility or to reduce muscle pain sensation) [58]. As we observed some substantial effects of foam rolling as an effective DOMS recovery modality, practical application for accelerated recovery after exercise might be crucial for athletic training or competing with short durations of rest [18]. Based on the examinations performed in the present study, the type of foam roller is irrelevant for the effects of foam rolling.

3 Apr 2020

PONE-D-20-05356

Does the roller type influence on recovery rate, thermal response and DOMS prevention?

PLOS ONE

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Reviewer #1: Yes

Reviewer #2: Yes

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

**********

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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 #1: Yes

Reviewer #2: Yes

**********

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Reviewer #1: The current manuscript looks to determine if there is a difference between foam roller type versus passive recovery following a bout of maximum effort jump squats. Thermal imaging was used to measure changes in blood flow via skin temperature and blood lactate was measured to gauge the effectiveness of the exercise and determine difference in immediate recovery. It was determined that the type of foam roller doesn’t affect the clearance of lactate or symptoms associated with DOMS, however, it was found to show some improvements versus passive recovery. While the manuscript is well written, I do believe it needs revisions before it can be published.

Reviewer #2: see uploaded document from the reviewer as an uploaded word document.

**********

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Reviewer #1: No

Reviewer #2: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

Submitted filename: PONE-D-20-05356.pdf

Click here for additional data file.

Submitted filename: plusone reveiw.docx

Click here for additional data file.

2 May 2020

REVIEWER #1

General

The current manuscript looks to determine if there is a difference between foam roller type versus passive recovery following a bout of maximum effort jump squats. Thermal imaging was used to measure changes in blood flow via skin temperature and blood lactate was measured to gauge the effectiveness of the exercise and determine difference in immediate recovery. It was determined that the type of foam roller doesn’t affect the clearance of lactate or symptoms associated with DOMS, however, it was found to show some improvements versus passive recovery. While the manuscript is well written, I do believe it needs revisions before it can be published.

COMMENTS

Abstract

Page 2, Lines 27-28: The first sentence should start out “The study…”

Page 2, Line 29: Males should be plural.

Page 2, Line 32: you should have [] around Tsk and LA to indicate abbreviations.

AUTHORS' RESPONSE: Included in the text.

Introduction

General

You switch back and forth between using the term roller vs. foam roller. You should pick one and make it consistent throughout.

AUTHORS' RESPONSE: This has been adressed – now we’re using foam roller throughout all manuscript.

Page 2, Line 50: It’s the first time you use the abbreviation of LA in the main body, so you need to write it out the first time, followed by the abbreviation.

AUTHORS' RESPONSE: Included in the text.

Page 3, Line 52: You use the provider “Physiotherapist”. However, many other healthcare professionals use foam rollers for treating athletes, so I would suggest making it more encompassing of all professions.

AUTHORS' RESPONSE: This part has been removed in order not to limit potential users.

Page 3, Lines 63-64: Your 1st sentence is confusing. What is it compared too? Not sure this sentence should be your lead. Your paragraph is talking about arterial flow, so maybe swap

AUTHORS' RESPONSE: This part has been rebuilded with suggested swaping between the 1st and 2nd sentences.

Page 3, Line 67: Remove the ‘a’ from the sentence.

AUTHORS' RESPONSE: Included in the text.

Page 3, Line 70: You need to write out DOMS the first time you use it. Don’t assume everyone knows what DOMS stands for.

AUTHORS' RESPONSE: Included in the text.

Page 4, Lines 105-107: I would include a statement about the foam rolling being a single bout so not to confuse since measurements are happening up to 96 hours.

AUTHORS' RESPONSE: Included in the text. Page 5, lines 117-118.

Methods

Page 4, Line 127-128: The first sentence needs a reference.

AUTHORS' RESPONSE: Included in the text.

Page 6, Line 134: You can delete IAT since you never use the abbreviation again.

AUTHORS' RESPONSE: It is used again in Results section both in the text and Tab. 2.

Page 6, Line 142: Same as above. ART is only used here.

AUTHORS' RESPONSE: It is used again in Tab. 2.

Page 6, Line 142: I believe you have a typo stating 20 minutes. Otherwise this sentence is very confusing.

AUTHORS' RESPONSE: This sentence has been improved.

Page 6, Lines 148-151: On your ROI you define thigh, both anterior and posterior, as going down to the ankle. Thigh is a Latin term meaning femur, so you need to change your terminology. Plus your two tight measurements include the two calf measures.

AUTHORS' RESPONSE: I'm not sure if I understand correctly your comment on femur, as thigh refers to „upper leg”. Not the femur exclusively. Of course it’s our fault with ankle and it should be one description for thigh and second for calf. This has been clarified. Page 7, lines 161-166.

Results

General

The figures in your results should show were any significant differences occur. They should stand-alone and a reader should be able to look at just the figures and know what the results say.

AUTHORS' RESPONSE: Unfortunatelly there were no significant differences in LA level (Fig. 1). On fig. 2 they are marked as follow:

significant difference

STH vs PAS

(p=0.008)

------------------------

GRID vs PAS

(p=0.003)

How was VAS measured? Where participants asked to think of a certain area, was it general body pain? You need to include more details about the measurement of VAS. Also, do you have a VAS score prior to exercise? If assume individuals would report 0 on a VAS scale before exercise, but this is not true. Previous studies have found that participants can report anywhere from a 1-3 on the VAS scale at baseline.

AUTHORS' RESPONSE: This issue has been adressed in methods section. Page 7, lines 158-160.

Page 8, Line 209: Pain was significantly reduced in all groups when?

AUTHORS' RESPONSE: This has been clarified in the text.

Discussion

Page 11, Lines 286-287: Your sentence starting off “Switching off by pressing…” is confusing. Consider revising for clarity.

AUTHORS' RESPONSE: Included in the text.

You don’t discuss any limitations in your discussion. I’m sure your study had some and they should always be included.

AUTHORS' RESPONSE: Included in the text.

Tables

Table 2 needs clarity in the legend. IAT, ART, and AFTER30 need to be defined as figures and tables should always stand alone.

AUTHORS' RESPONSE: Included in the text. Legend has been clarified.

Also, you have no symbol for p<0.001 in the legend.

AUTHORS' RESPONSE: Indeed, we added that.

REVIEWER #2

Review for Plus one

Abstract:

The abstract is written with many format/ writing issues: 1. The first paragraph is not a paragraph, and should be developed more that just one sentence. 2. Same for paragraph 2. 3. The overall writing is very confusing and at times does flow with any sense of organization. I suggest using something like intro, methods (Assessment, Timing and Treatments) then Results and Conclusion.

AUTHORS' RESPONSE: Included in the text.

Introduction:

Once again the first paragraph is not developed, and only has 2 sentences. Also the first paragraph leads me to think the paper is about lactate and Fatigue with no mention or hint of foam rolling. Paragraph 2 is also underdeveloped and needs to be expanded upon so that it discusses or sets up the paper for the topic of Foam rolling and DOMS.

AUTHORS' RESPONSE: Included in the text.

The use of IT in the paper specifically the intro is very confusing. I have a hard time following what “it” is in the many sentences.

AUTHORS' RESPONSE: This has been included in the text as well as English grammar check has been provided by AJE. Please see reference # BFF0-200A-BB08-7F0E-1A7C

Line 73 please explain further with a reference or 2 to back of this claim.,

AUTHORS' RESPONSE: Included in the text.

Reduce the use of phrases like on the other hand in the intro

AUTHORS' RESPONSE: Included in the text.

Line 84, consider reorganizing to move the paragraph closer to the front of the intro.

AUTHORS' RESPONSE: As above we are writing about general effects of FR, so placing this here as more detailed seems to be justified.

Finally please proof read the content as there are many writing and grammar mistakes in the introduction.

AUTHORS' RESPONSE: Included in the text. Manuscript was edited for proper English language, grammar, punctuation, spelling, and overall style by AJE, reference # BFF0-200A-BB08-7F0E-1A7C

Methods:

The methods section needs some rewriting as to develop more paragraphs that are not 1-2 sentences.

AUTHORS' RESPONSE: Included in the text.

I am not sure about the 1 minute squat jumps, could you explain what reference or reasoning suggested this time and exercise?

AUTHORS' RESPONSE: During maximal efforts, the anaerobic (lactic) system lasts from 45 seconds to 2 minutes [Swanwick & Matthews, 2018]. That is why we choose 1 min. As we could observe in our previous studies [Adamczyk et al., 2014; Adamczyk et al., 2016] that this time along with maximal engagement of participants creates conditions close to volitional exhausted. Along with high LA concentration (mean for all participants 10.16 ±2.87) ranged 4.8-18.9 mmol/L warrant us that this exercise will be eligible for research aim i.e. “…inducing a significant increase in blood lactate levels as an effect glycolytic nature of exercise”.

Line 124: can you explain what you mean by adaption, is this meant to be a familiarization or some kind of temperature balance.

AUTHORS' RESPONSE: Following explanation was added to the manuscript:

The purpose of the adaptation was to achieve a state of thermal balance in relation to the ambient temperature so that the obtained thermograms were reliable. Thanks to this, changes in the thermal image were the result of disturbances in production or heat dissipation as a result of the exercises [Ring & Ammer, 2012].

IS TSK the same as thermal imaging? They seem to be used interchangable at times.

AUTHORS' RESPONSE: Tsk means skin temperature as a result of thermal image measurement. Appropriate explanation has been included in the text.

Also the same occurs with rolling, foam rolling or self myofascial release. Please clarify all these.

AUTHORS' RESPONSE: We used foam roller as a self-myofascial release technique and only in this context it has been used in the text.

I think it might be helpful in the writing to have less acronyms at times I had to keep going back to look at some of them that should be spelled out. ROI region of interest, or immediately after the test.

AUTHORS' RESPONSE: To clarify this, we explained with every first use in each part of the manuscript.

Results:

Again I suggest removing the pronoun it and make the sentences stronger by stating what it is.

There are several 1 sentence paragraphs that need to be developed or included in other sections of the results.

AUTHORS' RESPONSE: Included in the text.

Discussion:

Blood lactate changes: would like to see a few more comparisons of post research on lacate to the found results. And what significance does the reference on cardio bring to this paper?

AUTHORS' RESPONSE: Included in the text. Page 10, lines 253-255

Please expand upon this section with more research refences to support or refute your findings. The massage paragraph needs to tie more into the relationship to foam rolling

AUTHORS' RESPONSE: Included in the text. Page 10, lines 259-263 / Page 11, lines 265-267 / Page 11, lines 273-274.

Line 254 when you say the results of research are you referring to your study or the literature. It is not clear.

AUTHORS' RESPONSE: REFERENCE INCLUDED in the text. Page 11, line 277

Overall in the temperature section, I think you need to bring in your results as the compare contrast to the references you are using in this sections

Line 286: the sentence starting with switching is not a sentence please correct

AUTHORS' RESPONSE: Included in the text.

DOMS conclusion section: too many times “in light of “ is used also please expand your results to comparisons of the literature

AUTHORS' RESPONSE: Included in the text.

Overall I think the concept is interesting and I think the idea of trying to determine if foam rolling (specifically a type of roller) has an effect on preventing DOMS and improving recovery could be helpful to rehabilitation and sports performance. The methods performed were adequate, however the paper is not written in way that helps to clearly set up the research question. The introduction is littered with bad grammar and improper usage of terms like it and acronyms. The discussion is not a good comparison of the your results to the current literature and creates confusion as to what is out there versus what you found.

I highly suggest some editing of this paper and or proof reading by someone else to catch the grammatical errors and typos. This would take a good project, which I liked reading about, more clear to the reader.

AUTHORS' RESPONSE: Included in the text. Manuscript was edited for proper English language, grammar, punctuation, spelling, and overall style by AJE, reference # BFF0-200A-BB08-7F0E-1A7C

Submitted filename: Response to Reviewers.docx

Click here for additional data file.

18 May 2020

PONE-D-20-05356R1

Does the type of foam roller influence the recovery rate, thermal response and DOMS prevention?

PLOS ONE

Dear Mr Adamczyk,

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.

==============================

ACADEMIC EDITOR: Myself, along with Reviewers' 1 and 2, thought that the manuscript was much improved with the edits of the resubmission. A member of PLOS ONE's Statistical Advisory Board was also asked to review the revised submission.  Please address the minor revision/comments of Reviewers 2 and 3, prior to acceptance.

==============================

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Kelly Naugle, PhD

Academic Editor

PLOS ONE

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Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #2: All comments have been addressed

Reviewer #3: (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 #1: Yes

Reviewer #2: Yes

Reviewer #3: Partly

**********

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

Reviewer #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

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 #1: Yes

Reviewer #2: Yes

Reviewer #3: 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 #1: Yes

Reviewer #2: Yes

Reviewer #3: Yes

**********

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 #1: Thank you for responding to my previous comments. I believe you have adequately answered all comments and the manuscript is ready for submission.

Reviewer #2: Much improvement on the writing and grammar. This was much easier to ready, thank you for the rewrites and the work put into editing.

Few minor notes:

Abstract paragraph 1: add foam into the correct spots

Still a few times that “it” is used and should be edited.

Line 93: expend upon how or why Hodgson questions long term affects

Line 139: what is the (REST acronym for) do you mean that REST is equal to adaptation and thermal images. If so that seems to be confusing.

Reference: please make sure the proper reference formats are being used throughout the entire reference sections.

Reviewer #3: In a randomized study of 33 males, pain levels were repeatedly assessed up to 96 hours post exercise using the Visual Analog Scale following foam rolling with smooth (STH), grid roller (GRID) or passive recovery (PAS). Additionally thermal imaging of skin temperature and blood lactate were repeatedly measured. In the PAS group, lactate concentration at 30 minutes was significantly lower than the other two groups. Pain scores decreased significantly in the STH group between 48 and 96 hours and systemic decreases in VAS scores were observed in the GRID group. No significant changes in VAS scores for the PAS group was observed.

Minor revisions:

1- In the abstract, indicate that the trial was randomized.

2- Move the sentences from lines 122-8 to the results section. Indicate the type of summary statistics provided in parenthesis.

3- Line 182: typographical error: Large effects had and eta-squared “>” 0.40.

4- Provide a summary table of the results corresponding to the details contained in lines 190-9. Include summary statistics, the overall p-value from the repeated measures ANOVA, and the pairwise Bonferroni corrected p-values (similar to Table 2).

5- Table 1: To conform to standard practice, transpose the matrix. List the groups in columns at the top and the biometric characteristics in the rows. Additionally, indicate that the summary values are means and standard deviations or standard errors of the means.

6- Table 2: Indicate the type of summary statistic following the +/- sign.

7- Be consistent with the notation for Tsk.

8- Page 21: Indicate if the confidence intervals shown on the graph were adjusted for repeated measures.

9- Recreate Figure 2 making it similar to Figure 1. Use a line plot and confidence intervals.

10- State and justify the study’s target sample size with a pre-study statistical power calculation. The power calculation should include: sample size, alpha level (indicating one or two-sided), minimal detectable difference and statistical testing method.

11- Indicate the date range subjects were enrolled in the study.

12- Clearly define the aims of the study.

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy.

Reviewer #1: No

Reviewer #2: No

Reviewer #3: No

[NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files to be viewed.]

While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email us at figures@plos.org. Please note that Supporting Information files do not need this step.

Submitted filename: plus one reveiw 2.docx

Click here for additional data file.

1 Jun 2020

Reviewer #2:

Much improvement on the writing and grammar. This was much easier to ready, thank you for the rewrites and the work put into editing.

Few minor notes:

Abstract paragraph 1: add foam into the correct spots

AUTHORS' RESPONSE: Included in lines 29 and 30.

Still a few times that “it” is used and should be edited.

AUTHORS' RESPONSE: Included and edited in lines 70, 79, 335 and also “it” has been removed in lines 112, 249, 280.

Line 93: expend upon how or why Hodgson questions long term affects

AUTHORS' RESPONSE: Included in lines 94-95.

Line 139: what is the (REST acronym for) do you mean that REST is equal to adaptation and thermal images. If so that seems to be confusing.

AUTHORS' RESPONSE: This has been clarified in line 142, as REST is acronym of resting state before exercise.

Reference: please make sure the proper reference formats are being used throughout the entire reference sections.

AUTHORS' RESPONSE: Included in the text.

Reviewer #3:

Minor revisions:

1- In the abstract, indicate that the trial was randomized.

AUTHORS' RESPONSE: Included in line 33.

2- Move the sentences from lines 122-8 to the results section.

AUTHORS' RESPONSE: We were not sure about this remark. Are we supposed to do this? As lines 122-8 are description of participants so we believe it should stay in this part of the paper not in results section. Anyway we added “Participants” subheading in here.

Indicate the type of summary statistics provided in parenthesis.

AUTHORS' RESPONSE: Included in the text.

3- Line 182: typographical error: Large effects had and eta-squared “>” 0.40.

AUTHORS' RESPONSE: Included in the text.

4- Provide a summary table of the results corresponding to the details contained in lines 190-9. Include summary statistics, the overall p-value from the repeated measures ANOVA, and the pairwise Bonferroni corrected p-values (similar to Table 2).

AUTHORS' RESPONSE: Included in the text.

5- Table 1: To conform to standard practice, transpose the matrix. List the groups in columns at the top and the biometric characteristics in the rows. Additionally, indicate that the summary values are means and standard deviations or standard errors of the means.

AUTHORS' RESPONSE: Included in the text.

6- Table 2: Indicate the type of summary statistic following the +/- sign.

AUTHORS' RESPONSE: Included in the text.

7- Be consistent with the notation for Tsk.

AUTHORS' RESPONSE: We included that, one place without down script in line 243 has been corrected.

8- Page 21: Indicate if the confidence intervals shown on the graph were adjusted for repeated measures.

AUTHORS' RESPONSE: Included in the text.

9- Recreate Figure 2 making it similar to Figure 1. Use a line plot and confidence intervals.

AUTHORS' RESPONSE: Included in the text.

10- State and justify the study’s target sample size with a pre-study statistical power calculation. The power calculation should include: sample size, alpha level (indicating one or two-sided), minimal detectable difference and statistical testing method.

AUTHORS' RESPONSE: Following statement has been added „For the sample size (3 groups, each n = 11), assuming a typical significance level alpha = 0.05 (two-way test) and the standardized effect RMSSE = 0.77, the test power was 0.88” – lines 181-182.

11- Indicate the date range subjects were enrolled in the study.

AUTHORS' RESPONSE: The study was conducted in October 2019. Each group performed test separately but experimental sessions for groups, were held at the same time of the day. We’ve included this statement in the text, lines 127-128.

12- Clearly define the aims of the study.

Aims has been clarified in lines 118-119.

Submitted filename: Response to Reviewers2.docx

Click here for additional data file.

11 Jun 2020

Does the type of foam roller influence the recovery rate, thermal response and DOMS prevention?

PONE-D-20-05356R2

Dear Dr. Adamczyk,

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.

An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org.

If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. 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.

Kind regards,

Kelly Naugle, PhD

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Please fix the following grammatical errors in the manuscript:

Abstract, Line 33: Change "In randomized trial, enrolled..." to "This randomized trial enrolled.."

Page 4, line 79: change "In research is also suggested..." to "Research also suggests..."

Page 5, line 118: Change "Whether the type of roller in single foam rolling treatment influence on the..." to "whether the type of roller in single foam rolling treatment influences the rate...".

Reviewers' comments:

18 Jun 2020

PONE-D-20-05356R2

Does the type of foam roller influence the recovery rate, thermal response and DOMS prevention?

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