The age distribution of the world's population stands in a constant change. An increase in the number of elderly people and a simultaneous decline in the number of younger people is a trending factor worldwide.[ Since the natural process of aging is defined as continuous and irreversible, a high life expectancy does not only entail advantages. Aging is associated with a reduction in both physical and cognitive functions of the human body, which also involves the likeliness in the occurrence of age-related diseases.[ Reduction in muscle strength and coordination of the lower extremities accompanied by decreased gait assurance and balance control are the result of a physical deterioration in an older body.[ Together with decreased cognitive functions, these impairments lead to a higher risk of falling among the elderly.[ Over 30% of people aged 65 or older, which is conventionally the chronological age that defines a person to be elderly,[ experience on average 1 fall a year.[ In order to prevent further consequences of such events, it is crucial to reduce the risk of falling among this population. Inactivity is meant to be a factor that accelerates the decrease of bodily functions[ with a negative impact on balance control.[ Physical activity has been therefore proven to counteract this phenomenon.[ There is however still uncertainty in which type of exercise may be the most effective to this purpose.[ Higher levels of physical activity reduce the overall morbidity and mortality and the risk of falling between 30% and 50%.[ Especially leg strength training and balance training have been identified as eligible methods to reduce the risk of falls. However, balance is the foundation of the ability to stand upright and move along, therefore balance training should also have an important role in fall prevention.[ It has been also proven that seniors with deteriorated balance are more likely to experience a fall than seniors with unimpaired postural control, which underlines the importance of balance training among the elderly.[ Almost all studies which investigate the risk of falling among elderly conclude that physical activity, even leisure exercises, are effective methods in order to maintain an intact balance control and prevent falls.[ Various studies have examined different kinds of exercise, from Pilates, stair climbing, vibration training to dancing.[ These have all found significant improvements in the ability to balance and provide evidence that physical activity can reduce the risk of falling. As most of them address only 1 specific kind of exercise or 1 kind of balance (either static, dynamic or intended as postural control), it is unsure which form of physical activity can provide the most beneficial effect. Therefore, the aim of this systematic review was to analyze different typologies of exercise directed to increase static balance in elderly adults and try to understand which of them is able to effectively promote such ability and may be of support in order to prevent the risk of falling.
The first range of articles was selected by title screening of the manuscripts. In this phase, articles matching the search terms and inclusion criteria were collected. Out of this first selection, the abstracts of the papers were read, followed by excluding those that did not meet the inclusion criteria. After duplicate removal, we proceeded with a qualitative synthesis of the full texts of the studies included. Two independent investigators conducted the literature search and performed the synthesis as follows: Study design; Sample (n); Intervention; and main results. The 2 independent investigators, in case of disagreements, resolved article inclusion by negotiation. Finally, full texts were read and a decision upon included articles was made. The included studies were all randomized controlled trials.
Statistical analysis
In the qualitative synthesis, the comparison of the intervention effect between the exercise and control groups was analyzed for each manuscript according to post-intervention data, or where accessible, the rate of pre-post improvement (i.e., mean differences or percentage change, %Δ). Subsequently, 95% confidence intervals (CIs) were calculated in order to increase homogeneity for the quantitative synthesis. The effect of the balance interventions was interpreted based on standardized mean differences and statistical significance between the exercise intervention group and the control group.
Results
A total of 1305 records have been identified through the preliminary database search. One hundred twelve studies were selected through title screening and 64 of these records were excluded after abstract analysis. Of the 48 records remaining, which the full texts were analyzed, 26 were excluded for not complying to the inclusion criteria. Twenty-two studies were considered potentially relevant and compliant with all the inclusion criteria. Subsequent to the retrieval of the %Δ between pre and post-intervention, calculated on the experimental group, 95% CIs were calculated for the articles included in the qualitative synthesis (C.I. based on the balance improvement after the interventions: CI lower 15.71 – CI upper 43.01) and based on such criteria a total of 8 studies were finally included in the quantitative synthesis. Figure 1 shows the selection process of the studies in detail.
Figure 1
Preferred Reporting Items for Review and Meta-Analyses (PRISMA) flow diagram illustrating the different phases of study inclusion.
Characteristics of studies included in the quantitative synthesis.
Characteristics of studies included in the quantitative synthesis.All analyzed studies exhibited improvements in the balance measures between pre and post intervention. The exercise protocol of each intervention is summarized in Table 2. The following section provides an overview of all studies followed by the main results.
Table 2
Description of the training protocols.
Description of the training protocols.
Resistance and aerobic exercise
Two of the retrieved records used resistance exercise as a form of exercise to increase balance in the elderly.[ The study of Ansai et al[ used a randomized, 3-arm controlled trial, in which a group of elderly performed a multicomponent exercise intervention which comprised a combination of aerobic and resistance exercise, another group performed a resistance exercise protocol and a control group which received no-intervention. The resistance exercise group carried out 3 sets of 10 to 12 maximal repetitions at moderate speed with a 1 minute rest between each set, with exercises for both upper and lower limbs. The aerobic component in the combined group consisted in 13 minutes on a cycle ergometer at an intensity of 60% to 85% of reserve heart rate (the protocol consisted of intensity increases and decreases every 3 minutes), adjusted for age and gender. The balance measure taken into account was the one leg stance, measured in seconds. The results indicated that after a 16 week intervention period both the multicomponent (pre 7.1 ± 8.6 s, post 11.1 ± 11.7 s) and resistance exercise intervention (pre 6.0 ± 6.7 s, post 6.7 ± 7.4 s) increased the balance measures compared to the control group which instead showed a decrease (pre 5.1 ± 6.5 s, post 5.5 ± 5.9 s). Also, the number of reported falls measured by the authors decreased after the intervention period (Multicomponent pre 10, post 2, Resistance exercise pre 7, post 1, control pre 8, post 5). It has to be noted that the multicomponent exercise intervention showed greater results compared to the resistance exercise protocol alone.Similar research design has been carried out by Sousa et al,[ where aerobic exercise alone has been compared to a combined aerobic and resistance exercise protocol to a control group in order to improve risk factors for fall preventions in the elderly. The combined exercise comprised an aerobic session once a week and a resistance exercise session once a week. The resistance training comprised 3 sets of 10 to 12 repetitions using a pyramidal method with increasing intensity from the first to the eighth training week. As in the study of Ansai et al, the exercises targeted both the upper and lower limbs. The aerobic component was composed of a 30 min brisk walking protocol. The time up and go test was used to assess balance performance. The results reported that both the aerobic and the combined intervention showed positive increases in the balance measures with a greater magnitude in the combined exercise program (Aerobic pre 7.7 ± 1.1, post 7.0 ± 0.8; Combined pre 7.4 ± 1.0, post 5.9 ± 0.7). The control group showed a mild decrease in the functional measures (pre 7.5 ± 0.7, post 7.7 ± 1.3).
Balance training
Two of the retrieved records used balance protocols[ to increase balance and reduce the fall rate in the elderly. The study of Leiros-Rodríguez and García-Soidan was a randomized control trial with an experimental group of 14 elderly women. The experimental group underwent a balance exercise intervention twice a week for 50 minutes for each session in which each participant performed 12 specific balance exercises simulating movements that the participants found instable in ordinary life tasks. The exercises were specific for static and dynamic balance. Each exercise lasted 60 seconds with a 60 second rest between each exercise and it was then repeated twice. When the tasks were deemed not demanding the investigators modified the size and characteristics of the support base surface of the elderly participants. The balance assessment was performed with the Berg Balance scale. At the end of the 6-week intervention, the experimental group increased the balance measure (Pre 45.86 ± 2.91; Post 54.07 ± 1.98), whereas a decrease was observed in the control group (Pre 47.79 ± 3.38; Post 47.71 ± 2.89).Zhao et al[ evaluated the effects of a specific balance protocol compared to a tai-chi intervention and a no-intervention group on balance measures. The experimental group underwent specific training in order to control the center of mass, range of motion and proprioception of the ankle joint and balance control. The tai-chi group performed a 10 form-yang-style tai-chi program, whereas the control group received no treatment. The chair stand test was used to assess balance and this was a component of the fall risk test to evaluate the risk of falling. An increase of 15.8% and 15.2% was achieved after the intervention in the balance measure in the experimental group and tai-chi group, respectively. An increase of around 5% was also achieved by the control group. There were no significant differences between the 2 groups regarding the balance measure. It is noteworthy that the experimental group also increased aerobic capacity, which was not achieved neither in the tai- chi nor the control group. Nevertheless, aerobic capacity is not a variable that has been considered in this review.
The only retrieved record evaluating aerobic step as a form of intervention to increase balance in the elderly is that of Dunsky et al.[ The authors implemented 2 protocols compared to a control group. The first using an aerobic step and the second using a stability ball. Both protocols were developed over a 45 minute session, twice a week for 8 consecutive weeks. The aerobic step protocol comprised 1 to 3 sets for each exercise with 8 to 15 repetitions per exercise of slow to medium speed performances using an aerobic step. The exercises were stepping on or over the step, walking around the step, with or without an overload ranging between 0.5 and 1 kg using or not using music to gain a rhythmic movement. The stability ball exercises comprised 1 to 3 sets for each exercise with 8 to 15 repetitions per exercise of slow to medium speed performances using a stability ball. The exercises were resistance exercises against body weight with the addition of a soft ball or a medicine ball of 0.5 or 1 kg. Such interventions might be considered as a form of combined aerobic and resistance exercise. The one leg stance was used to evaluate balance performance. The results of the study indicated that aerobic step was able to increase the one leg stand to a greater extent compared to the stability ball protocol (Aerobic step pre 13.1 ± 10.4 s, post 17.4 ± 11.9 s; Stability ball pre 14.6 ± 9.2 s, post 15.9 ± 11.6 s). Interestingly also in the study of Dunsky et al,[ the control group presented a decrease of the balance measures (pre 22.9 ± 12.1 s, post 23.0 ± 11.6 s).It is important to note that also in the above-mentioned protocols (Resistance and Aerobic Exercise and Balance Training) those which showed greater effects were those combining aerobic and anaerobic training, as the aerobic step activity in which anaerobic exercises were used in an aerobic manner.
Adapted physical activity and Wii Fit training
The only retrieved record evaluating adapted physical activity is that of Toulotte et al.[ The authors had as main aim to compare adapted physical activity to a Wii Fit training. The study design comprised 4 groups:An adapted physical activity group,a Wii Fit training group,a combined intervention group anda no-intervention control group.All participants exercised once a week for 60 minutes for 20 consecutive weeks. The adapted physical intervention consisted of exercises in which the participants were asked to increase the step length, step height, the mobility of the cervical rachis, and ocular mobility in order to develop muscular strength, proprioception, flexibility, static balance with eyes open and eyes closed and dynamic balance. The difficulty increased each training week by implementing the number of repetitions and the tasks required. The Wii Fit training consisted of standardized video games included with this console, such as heading soccer, ski jumping, yoga, downhill skiing, game balls, and tightrope walker. Each participant underwent the difficulty level that best fitted his abilities. The combined group underwent both the above-mentioned interventions with lower repetitions compared to the 2 single interventions alone and the control group underwent no physical activity intervention. Each participant was evaluated through the Tinetti test, the unipedal test, and the Wii Fit test. The results showed for group 1 and 3 that balance increased significantly: The Tinetti test decreased of 13% and 12%, respectively, in static (15%) and dynamic conditions (16%). The unipedal test reported a decreased number of balance losses (Group 1 pre 20, post 8; Group 3 pre 22, post 14) and Wii Fit test an improvement of 44%. The results for the group which underwent the Wii Fit training alone showed an improvement only in the Tinetti test with a reduction of 13% only in the static but not in the dynamic conditions. No significant improvement in the unipedal test and an increase of the measure in the Wii Fit test by 61%.A decrease in balance of 5% was shown in the control group regarding the Tinetti balance test.
Although the investigated studies exhibited positive effects on balance, indicating a reduction in the risk of falling, there were some aspects of the studies that do not make a comparison possible. The studies reported a concomitant increase in strength together with balance improvements. Multicomponent exercise with aerobic and anaerobic components seems to provide positive outcomes together with specific balance exercises integrated with resistance exercise means. The control groups which received no intervention, showed a decline in the ability to balance, suggesting that inactivity, more than a specific type of physical activity, plays a pivotal role in the elderly, in the mechanisms involved in maintaining balance. Regular physical activity including aerobic, anaerobic and proprioceptive components may be practiced in order to promote static balance in the elderly as a mean to reduce future risk of falling. There is however the need to compare such results with larger population studies.
Author contributions
Conceptualization: Giuseppe Battaglia, Marianna Bellafiore.Data curation: Giuseppe Battaglia, Marianna Bellafiore.Investigation: Ewan Thomas, Jessica Brusa.Methodology: Ewan Thomas.Project administration: Antonio Palma.Resources: Vincenza Leonardi.Supervision: Antonio Palma.Visualization: Jessica Brusa.Writing – original draft: Ewan Thomas, Antonino Patti.Writing – review & editing: Ewan Thomas, Antonio Palma, Marianna Bellafiore.
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