Effect of a pulmonary rehabilitation program combined with cognitive training on exercise tolerance and cognitive functions among Tunisian male patients with chronic obstructive pulmonary disease: A randomized controlled trial.

BACKGROUND: Cognitive impairment has been well described in patients with Chronic Obstructive Pulmonary Disease (COPD) in addition to cardiorespiratory disability. To reduce this impairment, researchers have recommended the use of single or combined exercise training. However, the combined effect of cognitive training (CT) and pulmonary rehabilitation (PR) program on selective cognitive abilities in patients with COPD has not been fully evaluated. Therefore, we aimed to assess the impact of PR combined with CT on 6 minutes walking test (6MWT) and cognitive parameters in Tunisian males' patients with COPD. METHODS: Thirty-nine patients with COPD were randomly assigned to an intervention group (n = 21, age = 65.3 ± 2.79) and a control group (n = 18, age = 65.3 ± 3.2). The intervention group underwent PR combined with CT, and the control group underwent only PR, three times per week for 3 months. The primary outcomes were 6MWT (6 minutes walking test -6MWT-parameters) and cognitive performance, as evaluated by Montreal cognitive assessments (MOCA) and P300 test. Secondary outcomes were patient's characteristics and spirometric data. These tests were measured at baseline and after 3 months of training programs. RESULTS: Results showed a significant improvement of the 6MWT distance after the rehabilitation period in both groups (p < .001). Moreover, both groups showed significant improvement (p < .001) in cognitive performance including MOCA score and P300 test latency in three midline electrodes. However, the improvement in cognitive performance was significantly greater in the PR+CT group than the PR group. CONCLUSION: In conclusion, although PR alone improves 6MWT parameters and cognitive function, the addition of CT to PR is more effective in improving cognitive abilities in patients with COPD. This combined approach may provide clinicians with a complementary therapeutic option for improving cognitive abilities in patients with COPD.

Effects of Different Levels of Weightlifting Training on Bone Mineral Density in a Group of Adolescents.

The aim of the current study was to evaluate the effects of different levels of weightlifting training on bone mineral density (BMD) at different body sites (whole body (WB), lumbar spine (LS), femoral neck (FN), upper limbs (UL) and lower limbs (LL)) in a group of adolescents. Three groups of pubertal boys aged 13-15 years were recruited, including a control group (which included 13 untrained adolescents), a moderately trained group (which included 13 non-elite weightlifters, with four sessions of 2 hours per week) and a highly trained group (which included 13 elite weightlifters, with eight sessions of 2 hours per week). The three groups were paired for age and maturation index (using Tanner stages). Body composition, bone mineral content (BMC) and BMD were evaluated by dual-energy X ray absorptiometry (DXA). Physical performance variables (including weightlifting specific exercises, counter movement jump and squat jump) were measured using validated methods. Results showed that the values of BMD and physical performance variables were greater in the group of elite weightlifters compared to the group of non-elite weightlifters and the control group. In addition, the values of BMD and physical performance variables were higher in the group of the non-elite weightlifters compared to those of the control group. After adjusting for lean mass and squat jump, lumbar spine BMD, FN BMD, UL BMD and LL BMD remained significantly higher in the elite weightlifters' group compared to the two other groups. In conclusion, the current study suggests that elite adolescent weightlifters have greater bone health parameters compared to moderately-trained adolescent weightlifters and untrained adolescents.

Relationship between the level of mental fatigue induced by a prolonged cognitive task and the degree of balance disturbance.

This study investigated the effects of mental fatigue (MF) induced by a 90-min AX-continuous performance test (AX-CPT) on balance control by addressing the issue of the heterogeneity of individuals' responses. Twenty healthy young active participants were recruited. They had to carry out two balance tasks (sway as little as possible on a stable support with the eyes open and closed) when standing on a force platform before and after performing a 90-min AX-CPT. The NASA-TLX test was used to assess the subjective manifestations of MF. Objective cognitive performance was measured using results from the AX-CPT. Inter-individual differences in behavioral deterioration due to MF were analyzed with a hierarchical cluster analysis, which categorizes participants' behaviors into subgroups with similar characteristics. The cluster analysis revealed that the achievement of the AX-CPT induced various levels of MF and balance impairments within the whole sample. A significant relationship between the level of MF and the degree of balance disturbance was observed only when participants stood with the eyes open, thus suggesting that inter-individual differences in vulnerability to MF could stem from differences between subjects in the level of engagement of visual attention and/or from differences in field dependency for balance control. These findings show that the completion of the same prolonged demanding cognitive task induces a strong heterogeneity in subjects' responses, with marked individual differences in MF vulnerability that affect balance control differently according to the sensory context.

Sensory electrical stimulation and postural balance: a comprehensive review.

PURPOSE: Sensory electrical stimulation (SES)-i.e., low-intensity electrical currents below, at, or just above the sensory threshold but below the motor threshold-is mainly used to restore/improve postural balance in pathological and healthy subjects. However, the ins and outs of its application as well as the neurophysiological effects induced are not yet well known. Hence, the aim of this paper was to address the effects of SES on postural balance based on these considerations. METHOD: The immediate/concurrent effects (SES applied during postural balance measurements), the acute effects (SES durably applied before measuring postural balance) and the chronic effects (SES included in training/rehabilitation programs, i.e., measurements performed before and after the programs) were analysed with a comprehensive review. RESULT: SES can lead to the improvement of postural balance using any of the three applications (immediate/concurrent, acute and chronic), notably in pathological subjects. The beneficial effects of SES can take place at the peripheral (sensory receptors sensitivity), spinal (spinal motoneural excitablity) and supra-spinal (cortex reorganisation or adaptation) levels. In healthy subjects, SES appears interesting, but too few studies have been conducted with this population to report clear results. Moreover, the literature is relatively devoid of comparative studies about the characteristics of the stimulation current (e.g., location, current parameters, duration). CONCLUSION: In practice, SES appears to be particularly useful to reinforce or restore the postural function in the immediate/concurrent, acute or chronic application in pathlogical populations while its effects should be confirmed in healthy sujects by future studies. Moreover, future research should focus on the different characteristics of stimulation.

Key performance indicators in Tour de France sailing.

This study aimed to determine the key performance indicators of inshore sailing during the sailing Tour de France. Technical and physical parameters were investigated to determine the discriminating factors between successful and less successful international level sailors. Measurements from 21 sailors (mean ± SD; age = 23.81 ± 4.18 years) were conducted prior to the sailing Tour de France. Global Positioning System data of all participating teams (n = 23) was analysed. Sailors were divided into two groups (i.e. successful and less successful) according to qualifying performance percentage. The differences between successful and less successful sailors were explored by means of independent t-tests. Results indicate that successful boats displayed higher maximal speed, higher average speed and more efficient starting performance per race than less successful boats. Successful sailors have stronger handgrip strength, higher isometric maximal voluntary force relative to bodyweight (isometric mid-thigh pull) and more powerful submaximal pulling (bench pull) actions than their less successful counterparts. The results of this study suggest that multiple sailing, physical and physiological variables are related to sailing performance in inshore sailing. Therefore, we emphasize the importance of integrating specific testing protocols to evaluate the performance potential of inshore sailors participating in the sailing Tour de France.

Balance control is impaired by mental fatigue due to the fulfilment of a continuous cognitive task or by the watching of a documentary.

The aim of the present study was to evaluate the effects of mental fatigue (MF) induced by a 90-min continuous demanding cognitive task on balance control. Twenty healthy young participants were recruited. They had to perform three postural tasks (on a stable support with eyes open, with eyes closed and on a wobble board) while standing on a force platform before and after watching a documentary in a control condition or carrying out a prolonged continuous demanding cognitive task (AX-continuous performance test-AX-CPT) in a MF condition. Results showed that performing the AX-CPT generated MF since participants felt a higher subjective workload from the NASA Task Load Index after the AX-CPT than after viewing the documentary. Both the AX-CPT and the viewing of the documentary impaired balance control, mainly by affecting postural regulatory mechanisms which evolved towards a less automatic and less complex regulation mode with an increased participation of cognitive resources. MF generated by the AX-CPT affected balance control by compromising the attentional processing, while the deleterious influence of watching a documentary on postural control could stem from an adverse effect of prolonged sitting on balance control during subsequent standing.

Acute and chronic neuromuscular electrical stimulation and postural balance: a review.

PURPOSE: Electro-induced (EI) muscle actions are largely used in healthy subjects to improve motor performance, in frail/older subjects to limit sarcopenia and mobility loss, and in pathological subjects to restore functional abilities after injury and/or surgical operation. Their effects on motor output (e.g., muscle strength and power, and motor performance) are relatively well known, but their effects on postural balance are not. However, postural balance turns out to be a determining factor for motor skills in terms of motor performance and prevention of falls (especially in older/frail and pathological subjects). Hence, this review addresses the acute and chronic effects of EI muscle actions on postural balance, comparing them to the effects of voluntary (VOL) muscle actions. METHOD: Narrative review. RESULT: In acute, fatigue-generating application, EI muscle actions impair postural balance but less than VOL muscle actions. In chronic application, EI muscle actions induce beneficial effects on postural balance in pathological and aged (or frail) subjects. However, they have no or very little impact on healthy and young subjects. In aged (and probably pathological) subjects, EI muscle actions alone or superimposed onto voluntary contractions (EI + VOL) are less efficient than VOL muscle actions in improving postural balance. CONCLUSION: In practice, as part of populations too frail/fragile or unable (sarcopenic or pathological persons) to regularly undertake VOL motor tasks required to efficiently struggle against the loss of mobility and the risk of fall, the EI muscle actions turn out to be particularly relevant to implement.

Influence of Weekly Workload on Physical, Biochemical and Psychological Characteristics in Professional Rugby Union Players Over a Competitive Season.

Dubois, R, Lyons, M, Paillard, T, Maurelli, O, and Prioux, J. Influence of weekly workload on physical, biochemical and psychological characteristics in professional rugby union players over a competitive season. J Strength Cond Res 34(2): 527-545, 2020-This study aimed to (a) quantify the physical workload (P-WL) during training and games throughout the professional rugby season and (b) analyze the influence of the season period and weekly-WL, at short (acute) and moderate (chronic) terms, on physical, biochemical, and psychological responses during the season. Physiological (physical and biochemical) responses to P-WL were analyzed by examining changes in the individual Z score of the Yo-Yo intermittent recovery test (YYIRT), submaximal aerobic tests (5'/5'-test), strength tests, countermovement jump tests, blood sampling, and "recovery-stress" scores (RESTq) in 14 professional players (26.9 ± 1.9 years). Changes throughout the season were analyzed using a linear mixed model to identify changes in P-WL, whereas repeated-measures analysis of variance was used to analyze changes in physiological responses across the season. The relationship between P-WL and physiological responses was analyzed using Pearson's correlation coefficient (r). The results showed that the preseason period comprised the highest level of P-WL compared with all other blocks across the season (p < 0.001). The acute P-WL, acute competitive-WL, and number of impacts seemed to be the WL parameters, which most influenced the physiological responses (changes in testosterone [T], cortisol [C], T/C ratio, IGF-1/C ratio, strength, and RESTq index). The chronic P-WL, particularly conditioning-WL, induced positive changes in fitness characteristics (YYIRT and 5'/5'-test). Finally, this study provides information to players and coaches alike as to the influence of P-WL on as well as adaptations in physiological and psychological indices throughout a playing season. This information can greatly inform the training and preparation of future players in different levels.

Correction to: Voluntary and electrically-induced muscle fatigue differently affect postural control mechanisms in unipedal stance.

In the metadata of the original publication of the article.

Effect of adding neuromuscular electrical stimulation training to pulmonary rehabilitation in patients with chronic obstructive pulmonary disease: randomized clinical trial.

OBJECTIVE:: To investigate the effectiveness of neuromuscular electrical stimulation added to pulmonary rehabilitation on walking tolerance and balance in patients with chronic obstructive pulmonary disease (COPD). DESIGN:: Randomized clinical trial. SETTING:: Outpatient, Faculty of Medicine of Sousse, Tunisia. SUBJECTS:: A total of 45 patients with COPD were assigned to an intervention group ( n = 25) or a control group ( n = 20). INTERVENTIONS:: The intervention group underwent a neuromuscular electrical stimulation added to pulmonary rehabilitation, and the control group underwent only a pulmonary rehabilitation, three times per week during six months. MAIN MEASURES:: Measures were taken at baseline and after six months of training. A stabilometric platform, time up and go, Berg balance scale tests, 6 minute walking test, and the maximal voluntary contraction were measured. RESULTS:: In the intervention group, an increase in an exercise tolerance manifested by a longer distance walked in 6 minute walking test 619.5 (39.6) m was observed in comparison to the control group 576.3 (31.5) m. The values of the time up and go, Berg balance scale, and maximal voluntary contraction in the intervention group at follow-up were significantly higher than those in the control group ( P = 0.02, P = 0.01, P = 0.0002, respectively). The center of pressure in the mediolateral and in the anteroposterior directions, as well as the center of pressure area was significantly more improved in open eyes and closed eyes in the intervention group compared to the control group ( P < 0.001). CONCLUSION:: The neuromuscular electrical stimulation added to pulmonary rehabilitation group benefited from better walking tolerance and greater balance improvement than the only pulmonary rehabilitation.

Ski Boots Do Not Impair Standing Balance by Restricting Ankle-Joint Mobility.

OBJECTIVE: This study was undertaken in order to provide new insight into sensorimotor control of posture when wearing high-shaft (HS) boots as ski boots. BACKGROUND: Previous studies into the effects of HS boots on postural control have produced controversial results. Some studies reported postural control impairments with ski boots in bipedal postural tasks due to ankle movement restrictions without quantifying the actual restrictive effect of these boots and specifying the adaptations of the postural control system. METHOD: Eighteen young healthy subjects took part in the experiment. Bilateral postural control was assessed on stable and unstable surfaces, while standing barefoot or wearing ski boots. Center of pressure (COP) parameters, ankle, knee, and hip joints movements were calculated and EMG activity from main postural muscles was recorded. RESULTS: Ski boots did not restrict the amplitude of ankle angular movements and largely impacted COP parameters and EMG activity on stable ground. In conditions of mediolateral instability, COP data illustrated an enhanced postural control in the frontal plane when wearing ski boots. CONCLUSIONS: Ski boots do not affect bipedal postural balance by restricting the ankle angular motions but induce complex adaptations of the postural control system which combine factors of a mechanical, motor, and sensorial nature. They impede postural control mainly when standing on stable ground without producing similar deleterious effects on unstable surfaces. APPLICATION: Our results show that HS boots as ski boots can improve lateral balance on unstable surfaces, which can contribute to prevent fall risk and ankle sprain.

Optimization of the Effects of Physical Activity on Plantar Sensation and Postural Control With Barefoot Exercises in Institutionalized Older Adults: A Pilot Study.

Increasing somatosensory information from the foot by exercising barefoot can potentially optimize the effectiveness of physical exercise interventions on falls prevention in the older adults. This pilot study was then undertaken to explore the effects of increased somatosensory information from the foot by exercising barefoot on balance, gait, and plantar cutaneous sensitivity in institutionalized older adults involved in multimodal exercise intervention. Participants were assigned to three groups: a control group which did not perform any physical exercise and two groups in which they were involved in a multimodal exercise program performed barefoot or shod. Postural, gait, and plantar cutaneous sensitivity parameters were collected. The results showed that the exercise program produced larger effects on balance and plantar cutaneous sensitivity when exercises were performed barefoot, without any noticeable effect on gait. Hence, barefoot exercising could be a relevant means to optimize the fall-prevention exercise programs in institutionalized older adults.

Fatigue does not conjointly alter postural and cognitive performance when standing in a shooting position under dual-task conditions.

This study investigated the effects of fatigue on balance control and cognitive performance in a standing shooting position. Nineteen soldiers were asked to stand while holding a rifle (single task - ST). They also had to perform this postural task while simultaneously completing a cognitive task (dual task - DT). Both the ST and DT were performed in pre- and post-fatigue conditions. In pre-fatigue, participants achieved better balance control in the DT than in the ST, thus suggesting that the increased cognitive activity associated with the DT improves balance control by shifting the attentional focus away from a highly automatised activity. In post-fatigue, balance control was degraded in both the ST and DT, while reaction time was enhanced in the first minutes following the fatiguing exercise without affecting the accuracy of response in the cognitive task, which highlights the relative independent effects of fatigue on balance control and cognitive performance.

Warm-up Optimizes Postural Control but Requires Some Minutes of Recovery.

Paillard, T, Kadri, MA, Nouar, MB, and Noé, F. Warm-up optimizes postural control but requires some minutes of recovery. J Strength Cond Res 32(10): 2725-2729, 2018-The aim was to compare monopedal postural control between the dominant leg (D-Leg) and the nondominant leg (ND-Leg) in pre- and post-warm-up conditions. Thirty healthy male sports science students were evaluated before and after a warm-up exercise (12 minutes of pedaling with an incremental effort on a cycle ergometer with a controlled workload). Monopodal postural control was assessed for the D- and ND-Legs before and immediately, 2, 5, 10, and 15 minutes after the warm-up exercise, using a force platform and calculating the displacement velocity of the center of foot pressure on the mediolateral (COPML velocity) and anteroposterior (COPAP velocity) axes. No significant difference was observed between the D-Leg and ND-Leg for both COPML and COPAP velocity in all the periods. In comparison with pre-warm-up, COPML decreased after 15-minute and 10-minute recovery periods for the D-Leg and the ND-Leg, respectively (p < 0.05), whereas COPAP decreased after 10-minute and 15-minute recovery periods (p < 0.001; p < 0.01, respectively) for the D-Leg, and after a 10-minute recovery period for the ND-Leg (p < 0.001). The warm-up optimized monopedal postural control but did not make it possible to distinguish a difference between the D-Leg and the ND-Leg. Some minutes of recovery are required between the end of the whole-body warm-up exercise and the beginning of the postural test to optimize postural control. The optimal duration of recovery turns out to be about 10-15 minutes.

Effects of training programs based on ipsilateral voluntary and stimulated contractions on muscle strength and monopedal postural control of the contralateral limb.

PURPOSE: To compare the effects of unilateral strength training by stimulated and voluntary contractions on muscle strength and monopedal postural control of the contralateral limb. METHODS: 36 non-active healthy male subjects were recruited and split randomly into three groups. Two groups of 12 subjects took part in a strength-training program (3 sessions a week over 8 weeks) comprising 43 contractions of the quadriceps femoris of the ipsilateral limb (at 20% of the MVC). One group carried out voluntary contractions exclusively (VOL group), while the other group benefited exclusively from electro-induced contractions (NMES group). The other 12 subjects formed the control (CON) group. Assessments of MVC and monopedal postural control in static and dynamic postural tasks were performed with the ipsilateral (ISPI) and contralateral (CONTRA) limbs before (PRE) and after (POST) completion of the training program. RESULTS: After the training program, the MVC of the IPSI and CONTRA limbs increased similarly for both experimental groups (VOL and NMES). There were no significant improvements of monopedal postural control for the IPSI or CONTRA limbs in either the VOL or NMES experimental group. No change was observed for the CON group over the protocol period. CONCLUSION: The purposed training program with NMES vs VOL contractions induced strength gains but did not permit any improvement of contralateral monopedal postural control in healthy young subjects. This has potential for therapeutic application and allows clinicians to focus their training programs on dynamic and poly-articular exercises to improve the postural control in young subjects.

Running and Metabolic Demands of Elite Rugby Union Assessed Using Traditional, Metabolic Power, and Heart Rate Monitoring Methods.

The aims of this study were (1) to analyze elite rugby union game demands using 3 different approaches: traditional, metabolic and heart rate-based methods (2) to explore the relationship between these methods and (3) to explore positional differences between the backs and forwards players. Time motion analysis and game demands of fourteen professional players (24.1 ± 3.4 y), over 5 European challenge cup games, were analyzed. Thresholds of 14.4 km·h-1, 20 W.kg-1 and 85% of maximal heart rate (HRmax) were set for high-intensity efforts across the three methods. The mean % of HRmax was 80.6 ± 4.3 % while 42.2 ± 16.5% of game time was spent above 85% of HRmax with no significant differences between the forwards and the backs. Our findings also show that the backs cover greater distances at high-speed than forwards (% difference: +35.2 ± 6.6%; p<0.01) while the forwards cover more distance than the backs (+26.8 ± 5.7%; p<0.05) in moderate-speed zone (10-14.4 km·h-1). However, no significant difference in high-metabolic power distance was found between the backs and forwards. Indeed, the high-metabolic power distances were greater than high-speed running distances of 24.8 ± 17.1% for the backs, and 53.4 ± 16.0% for the forwards with a significant difference (+29.6 ± 6.0% for the forwards; p<0.001) between the two groups. Nevertheless, nearly perfect correlations were found between the total distance assessed using the traditional approach and the metabolic power approach (r = 0.98). Furthermore, there is a strong association (r = 0.93) between the high-speed running distance (assessed using the traditional approach) and the high-metabolic power distance. The HR monitoring methods demonstrate clearly the high physiological demands of professional rugby games. The traditional and the metabolic-power approaches shows a close correlation concerning their relative values, nevertheless the difference in absolute values especially for the high-intensity thresholds demonstrates that the metabolic power approach may represent an interesting alternative to the traditional approaches used in evaluating the high-intensity running efforts required in rugby union games.

The difficulty of postural tasks amplifies the effects of fatigue on postural stability.

PURPOSE: It was supposed that the difficulty of postural tasks accentuates the effects of fatigue on postural stability. The aim of this work was to compare the effects of fatiguing running on three different postural conditions presenting different levels of difficulty: a standing still position with the eyes open (EO condition), a standing still position with the eyes closed (EC condition) and a shooting position with the eyes open (SP condition). The SP condition required a rifle to be held horizontally with the arms and a standing posture with the non-dominant foot ahead of the dominant foot. METHODS: Thirty-two male soldiers 32.2 ± 3.8 years old completed a maximal incremental protocol on a treadmill by running until they reached a state of fatigue. The three postural conditions were evaluated in a randomized order before and after the fatiguing exercise with the use of a force platform which recorded the displacements of the centre of foot pressure. RESULTS: Following the fatiguing running exercise, postural stability was affected to a greater extent in the SP condition than in the EO condition and the EC condition. CONCLUSION: The requirements of the SP condition modify the entire postural organization and this challenges balance control to a greater extent than when in EO and EC standing still positions, following fatiguing exercise. The difficulty of postural tasks thus amplifies the effects of fatigue on postural stability.

The impact of exercise on Alzheimer's disease progression.

INTRODUCTION: The preventive effects of chronic physical exercise (CPE) on Alzheimer's disease (AD) are now admitted by the scientific community. Curative effects of CPE are more disputed, but they deserve to be investigated, since CPE is a natural non-pharmacological alternative for the treatment of AD. AREAS COVERED: In this perspective, the authors discuss the impact of CPE on AD based on an exhaustive literature search using the electronic databases PubMed, ScienceDirect and Google Scholar. EXPERT OPINION: Aerobic exercise alone is probably not the unique solution and needs to be complemented by other exercises (physical activities) to optimize the slowing down of AD. Anaerobic, muscle strength and power, balance/coordination and meditative exercises may also help to slow down the AD progression. However, the scientific evidence does not allow a precise description of the best training program for patients with AD. Influential environmental conditions (e.g. social relations, outdoor or indoor exercise) should also be studied to optimize training programs aimed at slowing down the AD progression.

Intra- and inter-limb strength imbalance and asymmetry in soccer: A comparison of elite senior and junior players.

Evaluation of muscle strength imbalance can be an important element in optimizing the training process of soccer players. The purpose of the study was to examine isokinetic peak torque (PT) and total work (TW) exerted by both knee extensors (quadriceps or Q) and flexors (hamstrings or H), intra-limb imbalance and the magnitude and direction of inter-limb asymmetry in top elite senior (n = 109) and junior (n = 74) soccer players. An isokinetic dynamometry was used to measure maximum peak torque of quadriceps (PT-Q) and hamstrings (PT-H) at an angular velocity of 60° ·s-1, as well as the total work for extensors (TW-Q) and flexors (TW-H) at an angular velocity of 240° ·s-1 in the dominant (DL) and non-dominant leg (NDL) during concentric muscle contraction. Intra-limb imbalance and inter-limb asymmetries were calculated using a standard equation. Statistical analysis using t-test and Mann-Whitney U-test revealed: (a) no differences (p > 0.05) between groups for PT-Q and PT-H, (b) greater strength levels (p < 0.05) for TW-Q and TW-H of senior players than juniors, and (c) no differences (p > 0.05) between groups for intra-limb imbalance and inter-limb asymmetry. Additionally, Pearson's chi-kwadrat (χ2) analysis showed no differences (p > 0.05) between groups for intra-limb imbalance and inter-limb asymmetry in relation to the 'normative' values accepted in the literature that indicate an increase in the risk of knee injury. This study shows that isokinetic assessment can be an important tool to identify imbalances/asymmetries and to develop strategies to reduce the risk of muscle injury.