A high-intensity, intermittent exercise protocol and dynamic postural control in men and women

Temporal adaptation of the postural control following a prolonged fin swimming

PURPOSE

Postural control deteriorates following a transition between two environments, highlighting a sensory conflict when returning to natural conditions. Aquatic immersion offers new perspectives for studying postural control adaptation in transitional situations. Our aim is to study immediate and post-task static postural control adaptation on land after a prolonged fin swimming exercise in total immersion.

METHODS

Standing static postural control was assessed in 14 professional or recreational SCUBA divers (11 men, 3 women; 33.21 ± 10.70 years), with eyes open and closed, before, immediately after, and in the following 20 min following a fully-immersed 45-min fin swimming exercise. Centre-of-pressure metrics (COP) including average position, amplitude, velocity, length and 95% ellipse were evaluated in medial-lateral (x-axis) and anterior-posterior (y-axis) directions with a force platform. The Romberg ratio was also assessed for each metric.

RESULTS

A two-way repeated measures analysis of variance revealed a significant effect of the measurement period on COPx vel (p = 0.01), COPy vel (p < 0.01) and Length (p < 0.01), and of the visual condition on COPy vel (p < 0.01) and Length (p < 0.01). Eyes closed measures were systematically higher than eyes open measures despite there being no significant difference in the Romberg ratio in all periods. Post-immersion, the velocity and total trajectory of the centre of pressure remained systematically lower than baseline values in both visual conditions.

CONCLUSION

Post-immersion, COP velocity and length significantly decreased, suggesting a sensory reweighting strategy potentially associated with ankle stiffening.

Effects of photobiomodulation applied at different times on functional performance and ergogenic response of rugby athletes: Randomized clinical trial

BACKGROUND

Photobiomodulation (PBM) is indicated to accelerate the recovery of athletes and reduce muscle damage caused by physical exercise. The objective of this study was to establish the best time to apply photobiomodulation to increase the functional performance and ergogenic response of rugby athletes.

METHODS

Randomized crossover clinical trial with 18 rugby athletes of both sexes. The interventions were carried out from January to May 2019. The blood levels of creatine kinase (CK) and lactate, and performance in the Modified Star Excursion Balance Test, Single Hop Test, Triple Hop Test, Bangsbo Sprint test (BST), and Yo-Yo intermittent recovery level 1 (YoyoIR1) were evaluated. The athletes underwent two blocks of exercises with the BST and Yoyo-IR1, as well as the random application of four interventions: without application of photobiomodulation (CO), pre-exercise photobiomodulation (PBpre), PBM during the exercise interval (PBint), or post-exercise photobiomodulation (PBpos). The photobiomodulation using light-emitting diodes (850 nm, 8 J/cm2) lasted 10 min and was applied to the quadriceps, hamstrings, and triceps surae muscles. The results were compared between groups and times, and the effect size for the interventions was established.

RESULTS

No differences were found between groups in CK, lactate, and performance in the functional tests between groups and times. Only the PBpre presented improved performance in the first Yoyo-1R1 test (p < 0.01), while the PBint improved in the second Yoyo-IR1 test and BST (p < 0.05).

CONCLUSION

The PBM did not change muscle damage markers or performance in the functional tests. For an ergogenic response, photobiomodulation applied before exercise improves performance, which can be maintained when PBM is performed in the exercise interval.

Relationship between muscular extensibility, strength and stability and the transmission of impacts during fatigued running

The aim was to analyse the relationship between isokinetic strength, dynamic stability, muscular extensibility and impacts transmission during fatigued running. Low- and high-frequency impacts-related to body movements and the severity of impacts, respectively-were assessed in 17 male recreational runners, before and after a treadmill running fatigue protocol, using a triaxial accelerometry system. High-frequency impacts in the tibia were negatively correlated to the knee angle at which the quadriceps peak torque was reached (p = 0.014), and also to the extensibility of the hamstrings and soleus (p = 0.001 and p = 0.023, respectively). The increases of high-frequency impacts in tibia caused by fatigue were positively related to the knee angle at which the hamstrings peak torque was reached (p = 0.001) and to stability after landing (p = 0.007). The attenuation of high-frequency impacts was positively related to hamstrings/quadriceps ratio of strength (p = 0.010) and to stability (p = 0.006). Limiting possible deficits in hamstring and soleus range of motion, improving stability after landing, developing hamstring and quadriceps strength in elongated muscle range, and maintaining a balanced ratio of hamstring/quadriceps strength could help to reduce the injury risk in running.

The effect of a basketball game on balance ability: A study using a dual task paradigm

INTRODUCTION

Sports activity can affect balance ability, increasing injury risk. Single session of acute exercise can also alter cognitive function, potentially linked to balance ability. In this study, we examined the changes in cognitive function and static and dynamic balance abilities before and after the basketball game, and a dual-task was used to evaluate static balance ability.

METHOD

We measured the rating of perceived exertion (RPE), static and dynamic balance ability, and cognitive function in 12 male university basketball players before and after basketball game. We compared the differences in each measurement before and after the game using a t-test and examined the correlation between RPE, cognitive function, and balance ability.

RESULTS

We found RPE and cognitive function increased after the game. However, static balance ability in the dual-task and dynamic balance ability did not change before and after the game. Positive correlation found pre-RPE with SC-total and DO-locus length, and SEBT-ANT. Negative correlation found post-RPE with SEBT-PL, and positive correlation found ΔRPE with DO-peripheral area.

DISCUSSION

To enhance post-game balance ability, it is crucial to assess pre-game RPE for each player. Also, the understanding game-induced load is imperative as high post-game RPE negatively affects static and dynamic balance ability. Therefore, game load management strategies must be employed to ensure optimal balance ability.

CONCLUSION

Because RPE before and after a basketball game is related to balance ability after the game, it is important to understand the amount of load on the players.

Effect of Hamstring Tightness and Fatigue on Dynamic Stability and Agility in Physically Active Young Men

Hamstring extensibility has been defined as a factor to diminished dynamic stability and therefore increased risk of injury. The purpose of this study was to analyse the effects of hamstring tightness and fatigue on dynamic stability and agility. Nineteen participants were divided between the normal extensibility group (NEG) (n = 9, 82.2° ± 12.4°) and hamstrings tightness group (HTG) (n = 10, 64° ± 4.9°) using the passive straight leg raise test. To analyse dynamic stability and agility, they performed the modified Star Excursion Balance Test (mSEBT) and Dynamic Postural Stability Index (DPSI), and hexagon agility test, respectively, before and after a fatigue protocol. A two-way repeated measures ANOVA was used to determine differences among conditions: NEG vs. HTG, and rested vs. fatigued. HTG showed a significantly lower reach in the anterior direction in the mSEBT in pre- and post-fatigue than NEG. Participants in the NEG showed poor stability after landing in the mediolateral direction on DPSI post-fatigue. No significant changes were found in agility related with the group nor fatigue state. Participants with hamstring extensibility reduction has no differences in dynamic stability after landing nor agility after fatigue test, but significantly affects reaching distances during one-leg balance. As a conclusion, a reduction in range of motion in HTG was observed, but no other effects were observed on performance and dynamic stability after a local fatigue protocol depending on hamstring extensibility.

Combined effect of gender differences and fatiguing task on postural balance, functional mobility and fall risk in adults with multiple sclerosis: A preliminary study

AIM

To investigate the gender difference effect on postural balance, functional mobility, and fall risk after performing a fatiguing task in adults with multiple sclerosis (MS).

METHODS

Eleven women (30.91 ± 8.19 years) and seven men (30.29 ± 7.99 years) with relapsing-remitting MS performed a fatiguing task: three sets of the Five-repetition Sit-To-Stand Test (5-STST) were performed before and after the six-minute WalkTest (6MWT). Bipedal postural balance in eyes open and eyes closed conditions were assessed prefatigue (T0) and postfatigue (T3) using a force platform. Unipedal balance, functional mobility (Timed Up and Go Test), fall risk (Four Square Step Test) and fatigue [Visual Analogue Scale of Fatigue (VASF)] were assessed at T0 and T3. Heart rate (HR) and Rating of Perceived Exertion (RPE) were recorded before (only for HR), during and after the fatiguing task.

RESULTS

Compared to women, men showed an impairment of posturographic parameters [mean center of pressure (CoP) velocity (CoPVm) in both conditions (p < 0.05); CoP sway area (CoPAr) in both conditions (p < 0.01)], unipedal balance on the dominant leg (p <0.001), mobility (p<0.001) and an increased fall risk (p < 0.05). No gender differences were observed in 6MWT, 5-STST, HR, RPE, and VASF.

CONCLUSION

This preliminary study showed that fatiguing task negatively affected postural control, mobility and fall risk only in men. These gender differences were inconclusive but could be taken into account in postural balance rehabilitation programs for MS persons.

Effectiveness and response differences of a multidisciplinary workplace health promotion program for healthcare workers

Background

Workplace health promotion (WHP) in the healthcare industry is an important yet challenging issue to address, given the high workload, heterogeneity of work activities, and long work hours of healthcare workers (HCWs). This study aimed to investigate the effectiveness and response differences of a multidisciplinary WHP program conducted in HCWs.

Methods

This retrospective cohort study included HCWs participating in a multidisciplinary WHP program in five healthcare facilities. The 20-week intervention included multiple easy-to-access 90-min exercise classes, one 15-min nutrition consultation, and behavioral education. Pre- and post-interventional anthropometrics, body composition, and physical fitness (PF) were compared with paired sample t-tests. Response differences across sex, age, weight status, and shiftwork status were analyzed with a generalized estimating equation.

Results

A total of 302 HCWs were analyzed. The intervention effectively improved all anthropometric (body mass index, waist circumference, waist-hip ratio, and waist-to-height ratio), body composition (body fat percentage, muscle weight, visceral fat area), and PF (grip strength, high jump, sit-up, sit-and-reach, step test) parameters in all participants (all p < 0.05). Subgroup analyses revealed shift workers had a more significant mean reduction in body mass index than non-shift workers (adjusted p = 0.045). However, there was no significant response difference across sex, age, and weight subgroups.

Conclusion

This study suggested that a multidisciplinary WHP program can improve anthropometric and PF profiles regardless of sex, age, and weight status for HCWs, and shifter workers might benefit more from the intervention.

The Influence of Gender and the Specificity of Sports Activities on the Performance of Body Balance for Students of the Faculty of Physical Education and Sports

A sense of balance is required in sports activities, conditioning the quality of movements and physical performance. (1) The purpose of the study is to investigate the influence of gender and the specificity of sports activities on body balance. The investigated participants are 157 students of the Faculty of Physical Education and Sports/Bachelor’s degree: 109 men (age = 20.49 ± 2.03, body mass index, BMI = 22.96 ± 3.20), and 48 women (age = 20.21 ± 1.51, BMI = 21.05 ± 2.78). (2) Design: Cross-sectional study, with the definition of the variables gender and sport activity with three stages (non-athletes/NA, team sports games/TSG, and individual sports/IS). The evaluation was based on four dynamic balance tests (Bass test/points, Functional reach test/cm, Fukuda test/degrees of rotation, and Walk and turn field sobriety test/errors) and three static balance tests (Flamingo test/falls, Stork test, and One-leg standing test with eyes closed/s). (3) Results: The variance analysis (multivariate and univariate tests) indicates the superiority of women in most tests applied, but with significantly better values (p < 0.05) only for the Flamingo test and Bass test. Men have superior results only for vestibular stability (Fukuda test) and One-leg standing test, but it is statistically insignificant (p > 0.05). The TSG group has slightly better values than the IS group for the whole set of tests conducted, but these are not statistically significant (p > 0.05), so we cannot highlight the certain superiority of TSG practitioners over those involved in IS. Both the TSG and the IS group outperformed all tests compared to the NA group, with significant differences (p < 0.05), especially for the TSG. Conclusion: Women have better values than men on most tests, and performance sports students have higher average scores than those in the NA group, which demonstrates the beneficial influence of specific training on static and dynamic postural stability.

Dynamic postural control and physical stress: an approach to determining injury risk in real sporting conditions

Dynamic postural control is one of the essential factors in situations where non-contact injuries mainly occur, i.e., landing, cutting, or stopping. Therefore, testing of dynamic postural control should be implemented in injury risk assessment. Moreover, non-contact injuries mainly occur under loaded conditions when the athlete is physically stressed. Therefore, risk factors and mechanisms of these injuries should also be regarded under loading conditions and not only when the athlete is recovered. Current studies examining the influence of physical load on risk factors, such as dynamic postural control, often use cycling protocols to stress the participants. Nevertheless, most types of sports require running as a central element and the induced internal load after cycling might not be the same after running. Therefore, the current study aimed to examine the influence of a running and a cycling protocol on dynamic postural control and to determine the potential injury risk under representative conditions. In total, 128 sport students (64 males and 64 females, age: 23.64 ± 2.44, height: 176.54 ± 8.96 cm, weight: 68.85 ± 10.98 kg) participated in the study. They were tested with the Y Balance Test before and after one loading protocol. A total of 64 participants completed a protocol on a cycle ergometer and the other 64 on a treadmill. A mixed ANOVA showed significant interactions of time and load type. Dynamic postural control was reduced immediately after cycling but did not change after running. These findings indicate a load type dependence of dynamic postural control that must be considered while assessing an athlete’s potential injury risk and they support the need for more representative designs.

Fatigue of hip abductor muscles implies neuromuscular and kinematic adaptations of the ankle during dynamic balance

OBJECTIVE

Determine whether hip abductor muscle fatigue influenced ankle kinematic and muscle activity during ankle-destabilized tasks.

DESIGN

Cross-sectional study.

METHODS

Twenty-six healthy, active participants performed two tests (Star Excursion Balance Test, SEBT; Weight Bearing Inversion Test, WBIT) for assessment of dynamic balance and ability to control inversion. Participants were equipped with an ankle-destabilizing sandal in inversion and eversion to perform both tests, which were completed before and after a fatiguing exercise of hip abductor muscles (up to 50% reduction in strength). Electromyographic activity of peroneus longus (PL) and brevis (PB), tibialis anterior, gastrocnemius lateralis (GastL) and gluteus medius (GlutM) muscles were recorded. In addition, ankle kinematics were recorded using an inertial measurement unit.

RESULTS

Hip abductor fatigue induced a significant decrease in SEBT scores in three directions (p < 0.01). During SEBT, ankle supination decreased by 3.2° in the anterior and posteromedial directions (p < 0.01). Muscle activity of GastL increased during achievement of three directions (p < 0.05) in response to hip abductor fatigue. In posteromedial direction, PL (p < 0.001) and GlutM (p < 0.01) activity increased with fatigue. During WBIT, inversion angular velocity was not impacted by fatigue while, PB and GastL activity increased after fatiguing exercise (p < 0.005).

CONCLUSION

A decrease in SEBT performance and EMG adaptations with proximal fatigue attest to the importance of the hip abductor muscle in dynamic postural control. This could have important implications in building injury prevention programs. Changes in ankle supination may reflect a protective strategy of the joint in response to hip fatigue.

Effect of exhaustion on dynamic balance of professional padel players

Padel is an intermittent multidirectional racket sport that uses tennis’ rules and its scoring system. The popularity of padel has seen exponential growth; becoming one of the most practiced sports in the world. Balance constitutes a central component of racquet sports competitive demands. The aim of this study was exploring the effect of an exhaustive exercise on dynamic balance in elite padel players. 34 first division padel players with national rankings (age: 31.6 ± 7.9 years, height: 181.1 cm ± 5.26 cm; body mass: 81.1 kg ± 9.95 kg) volunteered for this study. Subjects were first tested for dynamic balance using the Y balance test. Then, they performed a volitional exhaustion test, followed by a dynamic balance retest. A significant main effect of condition for all balance variables was detected (all p < 0.03) except for the postero-lateral distance. A significant main effect of time was only found for the anterior distance (p < 0.001). Significant condition*time interaction was found for all variables (p < 0.02) except for the posterolateral distance. Posthoc analysis of the condition × time interaction indicated that compared to the control condition, exhaustive exercise deteriorated balance as showed by the significant decrease in the composite score (p = 0.05) and in the anterior direction (p < 0.001). This makes us focus on elaborating novel training systems in padel to improve the anterior direction distance after fatigue, being the reason of the decrease of dynamic balance capacity. This will boost the possibilities of scoring during a competitive situation.

Load-Induced Changes of Inter-Limb Asymmetries in Dynamic Postural Control in Healthy Subjects

Inter-limb asymmetries are associated with a higher potential risk for non-contact injuries. Differences in function or performance between the limbs might lead to imbalances and promote instability, increasing the potential risk for injuries. Consequently, an investigation of inter-limb asymmetries should be included in injury risk assessment. Furthermore, since non-contact injuries mainly occur under loaded conditions, an investigation of load-induced changes of inter-limb asymmetries can provide additional information on the athlete’s potential injury risk. Therefore, the current study aimed to investigate the influence of physical load on inter-limb asymmetries in dynamic postural control, which is essential in situations with a high risk for non-contact injuries such as landing, cutting, or stopping. In total, dynamic postural control of 128 active and healthy subjects (64 males and 64 females, age: 23.64 ± 2.44, height: 176.54 ± 8.96 cm, weight: 68.85 ± 10.98 kg) was examined. Dynamic postural control was tested with the Y-Balance Test (YBT) before and after a loading protocol on a bicycle ergometer or a treadmill. The results showed no significant increase of the inter-limb asymmetries in anterior direction [F_{(1, 126)} = 4.44, p = 0.04, η²_p = 0.03]. Moreover, there is high variation between the subjects regarding the magnitude and the direction of the asymmetries and the changes due to load. Therefore, a more individual analysis considering the magnitude and the direction of the asymmetries is required. Thereby, considering different modifying factors, e.g., sex, injury history, and baseline level of asymmetries, can be helpful. Moreover, an analysis of the changes during load might provide further insights, reveal possible differences, and help detect the reasons and mechanisms underlying inter-limb asymmetries and asymmetrical loading.

Does induced fatigue alter dynamic balance in athletes? A systematic review

OBJECTIVES

To determine the influence of induced fatigue on dynamic balance in healthy athletes.

DESIGN

Systematic review.

DATA SOURCES

PUBMED, MEDLINE, CINAHL, Sports Discus, and the Cochrane library from onset to May 28, 2019.

ELIGIBILITY CRITERIA

Eligible studies included any study examining the effects of induced-fatigue on dynamic balance, as measured by the SEBT/YBT, in healthy athletic populations. Studies with a low risk of bias were considered scientifically admissible for a best evidence synthesis.

RESULTS

Fifteen studies with low risk of bias were included - seven investigated recreational athletes while eight focused on competitive athletes. In the recreational population, five of the studies found significant decrease in dynamic balance following the fatiguing intervention. However, the remaining two concluded with insignificant changes. As for the competitive population, three studies showed significant effects of induced fatigue on dynamic balance, while five showed no effects.

CONCLUSION

There are conflicting results regarding the effects of induced fatigue on dynamic balance. The majority of studies focused on competitive athletes found that fatigue did not alter their dynamic balance. Per contra, the majority of studies focused on recreational athletes concluded the opposite - fatigue did indeed affect dynamic balance.

The Disturbing Effect of Neuromuscular Fatigue on Postural Control Is Accentuated in the Premenstrual Phase in Female Athletes

This study explored the fatigue effect on postural control (PC) across menstrual cycle phases (MCPs) in female athletes. Isometric maximal voluntary contraction (IMVC), the center of pressure sway area (CoParea), CoP length in the medio-lateral (CoP_LX) and antero-posterior (CoP_LY) directions, and Y-balance test (YBT) were assessed before and after a fatiguing exercise during the follicular phase (FP), mid-luteal phase (LP), and premenstrual phase (PMP). Baseline normalized reach distances (NRDs) for the YBT were lower (p = 0.00) in the PMP compared to others MCPs, but the IMVC, CoParea, CoP_LX, and CoP_LY remained unchanged. After exercise, the IMVC and the NRD decrease was higher at PMP compared to FP (p = 0.00) and LP (p = 0.00). The CoParea, CoP_LX, and CoP_LY increase was higher in the PMP compared to FP (p = 0.00) and LP (p = 0.00). It was concluded that there is an accentuated PC impairment after exercise observed at PMP.

Effect of sex and fatigue on quiet standing and dynamic balance and lower extremity muscle stiffness

PURPOSE

The purpose of the present study was to determine whether there are sex differences in fatigue-induced changes in quiet standing and dynamic balance and establish whether changes in muscle torque and resting stiffness may explain the potential sex differences in balance responses.

METHODS

Sixteen recreationally active men (age; 24.8 ± 5.0 years, height; 178.2 ± 5.6 cm, mass; 77.8 ± 13.2 kg) and 10 women (age; 21.0 ± 1.6 years, height; 167 ± 5.3 cm, mass; 61.3 ± 8.9 kg) were assessed for postural sway, Y balance test performance, isokinetic and isometric knee extensor torque and resting stiffness of the vastus lateralis (VL), gastrocnemius lateralis (GL) and Achilles tendon (AT) before and immediately after fatiguing exercise. The fatigue protocol consisted of five sets of 20-drop jumps.

RESULTS

The fatiguing exercise elicited similar magnitude (effects size; ES) reductions in muscle torque (men; ES = 0.45-0.80, women; ES = 0.46-0.52), dynamic balance (men; ES = 0.45-0.74, women; ES = 0.47-0.79) and resting VL stiffness (men; ES = 0.46, women; ES = 0.36) in men and women (all p < 0.05). For quiet standing balance, fatigue induced an increase in postural sway metrics (ES = 0.64-1.28) and reduction in resting GL stiffness (ES = 0.40) in men (both p < 0.001) but not women (p > 0.05).

CONCLUSION

Fatiguing exercise, when producing a similar level of force reduction, induces similar magnitude reductions in dynamic postural control and resting VL stiffness in men and women. Distinct deteriorations in quiet standing balance in men but not women were accompanied by modifications in calf muscle stiffness following exercise-induced muscle fatigue.

Rating of perceived exertion (RPE) in studies of fatigue-induced postural control alterations in healthy adults: Scoping review of quantitative evidence

BACKGROUND

Amongst the literature researching the effects of exercise-induced fatigue on postural control in healthy adults, many studies have used the Borg scales to document the rating of perceived exertion (RPE) and have shown a broad range of RPE values. Our main aim was to map fatigue-induced RPE values in included publications. Secondary aims were to summarize the preference and purpose for the use of Borg scales within the included publications and to explore the potential associations between fatigue-induced RPE values and postural control changes.

METHODS

Five databases (Ovid Medline, PubMed, CINAHL, Scopus, and SPORTDiscus) were systematically searched for synthesizing data among the publications that reported RPE values on the Borg RPE- and Category-Ratio (CR) 10 scales and also found fatigue effects on postural control in healthy adults. Spearman's rank correlations were conducted to assess potential associations between fatigue-induced RPE values and maximal postural control changes across the included publications (group data).

RESULTS

45 of 51 studies included in this review reported maximal RPE values following exercise and ranged from 10.4-20 (6-20 Borg RPE) or 0.9-10 (CR10) indicating "very light" or "very weak" to "maximal" exertions. The 6-20 Borg and CR10 scales were mainly used to assess cardiovascular and muscular exertion, respectively. The scales were used mostly to estimate fatigue levels (n = 45), and to a lesser extent to produce a specific exercise intensity (n = 5) and as the criterion for exercise termination (n = 1). In general, there was no significant association between RPE and postural control changes across studies.

CONCLUSION

The broad range of RPE values and weak correlations may suggest that various fatigue levels can lead to postural control changes. However, one should be careful in comparing the extent of fatigue from RPE values and its potential effect on postural control in the light of many confounding factors.

Gender differences in postural balance, physical activity level, BMI, and body composition in athletes with visual impairment

The aim of this study was to examine the gender differences in postural balance, physical activity (PA), and body mass index (BMI) and body composition in visually impaired (VI) athletes. A total of 66 athletes took part in this study. After anthropometric measurements, the PA level was assessed by the International Physical Activity Questionnaire-Short Form. The modified Clinical Test of Sensory Integration and Balance tool was used to assess postural balance in four standing conditions: (1) eyes-open on a firm surface, (2) eyes-closed on a firm surface, (3) eyes-open on a compliant surface, and (4) eyes closed on a compliant surface. Findings revealed gender differences in anthropometric measurements ( p < .05). No statistically significant differences were found in fat mass and fat free mass between sighted male and VI male athletes and between sighted female and VI female athletes ( p > .05). Weekly, high and moderate PA levels as well as walking were found to be different across the four groups ( p < .05). Assessment of postural balance in four standing conditions revealed no gender differences in sighted athletes ( p > .05). Postural balance scores in conditions 1 and 3 showed significant gender differences ( p < .05), whereas conditions 2 and 4 showed no gender differences in athletes with VI ( p > .05). Gender-matched differences were also apparent in conditions 1 and 3, revealing that VI male and female athletes scored worse in these conditions than their sighted male and female counterparts ( p < .05). There is a delay in balance parameter in VI athletes even if their fitness levels are similar with their sighted counterparts. The present findings could also be useful for gender-specific training session preparations in VI sports.

The interaction of acute physical fatigue with three traditional functional performance tests and the reactive balance test

OBJECTIVES

To assess the impact of acute physical fatigue on traditional and neurocognitive functional performance tests in recreational athletes.

DESIGN

randomized counterbalanced cross-over study, pre-post design SETTING: laboratory PARTICIPANTS: Twenty recreational athletes (age = 24 ± 3 years) MAIN OUTCOME MEASURES: We evaluated fatigue impairments following a 30 s all-out effort in three traditional and one neurocognitive functional performance test. The traditional functional performance tests encompassed the single leg hop for distance (SLH), countermovement jump (CMJ) and Y-balance test (YBT). The neurocognitive functional performance test encompassed the reactive balance test (RBT). A 30 s modified Wingate was used to induce acute physical fatigue.

RESULTS

Acute physical fatigue was successfully induced as indicated by a significant increase in heart rate, systolic blood pressure, blood lactate levels and rating of perceived exertion (p < 0.001). Acute physical fatigue induced significant decreases in RBT accuracy (p = 0.004) and SLH performance (p < 0.001). YBT, CMJ and RBT visuomotor reaction time remained unaffected by acute physical fatigue.

CONCLUSIONS

Acute physical fatigue impairs SLH performance and decreases accuracy in the RBT. YBT and CMJ performance remained unaffected by acute physical fatigue. Clinicians should be aware of this divergent neurocognitive functional impairments caused by one all-out effort to allow well-informed selection of functional performance tests.

The Effect of High-Intensity Intermittent Training on the Acute Gait Plantar Pressure in Healthy Young Adults

High-intensity intermittent training (HIIT) has been successfully applied in various sports activities, as HIIT was considered as one of the most efficient training methods of exercise for improving physical performance and reducing the weight of overweight individuals. However, its acute effects of HIIT on gait and balance performance were not addressed. Thus, in this study we examined the acute effects of HIIT on dynamic postural control compared with steady-state training (SST) by analyzing plantar pressure parameters. In this study, sixteen healthy male adults were examined in 3 days. After exhaustive ramp-like cycle ergometer testing, the maximal heart rate (HRmax) of each participant was determined on the first day, then either a 20 minutes HIIT at 80–90% of HRmax or a 20 minutes SST at 60% of HRmax was randomly performed on the second and third day, respectively. Plantar pressure parameters were collected at comfortable walking velocity immediately after HIIT and SST respectively, and compared with the baseline data of plantar pressure gathered before maximal ramp test on the first day. The results showed significant differences in the plantar pressure in these three conditions of gait. Compared to pre-intervention and pre-SST, peak pressure and maximum force in the middle and lateral metatarsal increased significantly in post-HIIT. Meanwhile, the foot balance data indicate that post-HIIT exhibits more foot pronation than baseline. The center of pressure (COP) trajectory was medially shifted during the stance phase in post-SST, and noticeably in post-HIIT. The displacement and velocity of medial-lateral COP in the initial contact phase were greater in post-HIIT; while during the forefoot contact phase, post-HIIT showed fewer time percentages and greater velocity of medial-lateral COP. In conclusion, a single high-intensity intermittent training session adversely affected the acute dynamic postural control than steady-state training in healthy male adults.

The Influence of Physical Load on Dynamic Postural Control-A Systematic Replication Study

Dynamic postural control is challenged during many actions in sport such as when landing or cutting. A decrease of dynamic postural control is one possible risk factor for non-contact injuries. Moreover, these injuries mainly occur under loading conditions. Hence, to assess an athlete's injury risk properly, it is essential to know how dynamic postural control is influenced by physical load. Therefore, the study's objective was to examine the influence of maximal anaerobic load on dynamic postural control. Sixty-four sport students (32 males and 32 females, age: 24.11 ± 2.42, height: 175.53 ± 8.17 cm, weight: 67.16 ± 10.08 kg) were tested with the Y-Balance Test before and after a Wingate Anaerobic Test on a bicycle ergometer. In both legs, reach distances (anterior) and composite scores were statistically significantly reduced immediately after the loading protocol. The values almost returned to pre-load levels in about 20 min post-load. Overall, findings indicate an acute negative effect of load on dynamic postural control and a higher potential injury risk during a period of about 20 min post-load. To assess an athlete's sports-specific injury risk, we recommend testing dynamic postural control under loaded conditions.

The effect of match fatigue in elite badminton players using plantar pressure measurements and the implications to injury mechanisms

The purpose of this study was to investigate the differences in plantar pressure under the lead and trail foot between two lunge tasks to the net in the dominant (LD) and non-dominant (LND) directions, and to explore how fatigue affects the plantar pressure patterns whilst performing movements before and after a competitive match. Peak and mean pressure were measured with the Biofoot-IBV in-shoe system from five repetitions of each task, with sensors positioned under the calcaneus, midfoot and phalanges on the lead and trail foot. Data were collected pre and immediately post-playing an official first national league competition match. The study was conducted with a sample of thirteen first league badminton players. A 2 × 2 repeated ANOVA found significant differences between the two tasks and between pre- and post-match (fatigued state). Players also had different foot pressure distributions for the LD and LND tasks, which indicated a difference in loading strategy. In a fatigued state, the plantar pressure shifted to the medial aspect of the midfoot in the trail limb, indicating a reduction in control and a higher injury risk during non-dominant lunge tasks.

Does Fatigue Impact Static and Dynamic Balance Variables in Athletes with a Previous Ankle Injury?

Ankle injury, resulting in deficits in static and dynamic balance, can result in significant time loss to sport, affect daily activities and potentially place athletes at greater risk of re-injury. In order to identify athletes at risk of ankle injury accurate and reliable balance assessment tools are required. The purpose of the current study was to quantify reliability of static and dynamic balance variables in currently healthy, previously injured, athletes (n = 19) and assess the impact of an intense intermittent zig-zag running protocol to volitional exhaustion, rated by RPE, on balance variables. A test re-test design assessed short-term reliability and measurement error by computing ICC and 95% limits of agreement (LoA). The Y balance test was deemed a reliable measuring tool for assessing dynamic balance, recording strong reliability (ICC = 0.96, 95% LoA from -95.7 to 105.8%). A HURlabs iBalance force platform assessed the static balance variables sway velocity and C90area; sway velocity (mmˑs-1) recorded strong reliability (ICC = 0.79). Significant post-fatiguing protocol increases (p < 0.001) were detected in single-leg static balance for both C90area (mm2) and sway velocity (mmˑs-1) assessed on stable and unstable surfaces (stable: 227 ± 84 vs. 366 ± 146 mm2 and 18.6 ± 4.2 vs. 22.9 ± 5.3 mmˑs-1: unstable; 275 ± 128 vs. 370 ± 140 mm2 and 19.3 ± 4.3 vs. 21.5 ± 4.0 mmˑs-1). Non-significant post-fatiguing protocol differences (p > 0.05) were detected in dynamic balance variables (anterior, posteromedial, posterolateral and composite reach scores) measured at 4-min after completing the protocol. Further research should investigate the effects of fatigue on dynamic YBT variables immediately post-exercise and determine if differences exist when comparing previously injured and un-injured limbs.

Normative Data Set of SWAY Balance Mobile Assessment in Pediatric Athletes

OBJECTIVE

To examine and describe normative values for an objective, mobile measure of postural stability commonly used in concussion assessments, SWAY Balance (SWAY Medical, Tulsa, Oklahoma).

DESIGN

Retrospective analysis of baseline balance assessments in a healthy pediatric population.

SETTING

Baseline assessments completed by certified athletic trainers at an outpatient concussion center or sports medicine offices in Philadelphia, PA and surrounding suburban Pennsylvania and New Jersey or during an athletic trainer's baseline assessment of collegiate athletes at a National Collegiate Athletic Association (NCAA) Division-II University in Fort Lauderdale, FL.

PARTICIPANTS

Test results of a sample of 466 athletes aged 5 to 18 years were included.

INTERVENTIONS

The SWAY Balance test was administered using a mobile device on all participants as part of a standard preseason, baseline evaluation, following the standard evaluation protocol.

MAIN OUTCOME MEASURES

Baseline SWAY Balance mobile assessment balance and reaction time scores, age and sex effects, were examined.

RESULTS

Normative scores are described, with results stratified into 4 age groups (5-9, 10-12, 13-17, and 18 years old). Balance scores, overall and within each individual stance score, improved with the age of the participants. Sex effects on balance were only seen in single-leg stances, with females outperforming males. Reaction time was found to be faster in males and improved with age, peaking at 13 to 17 years old and slowing in 18-year-olds.

CONCLUSIONS

Normative, age-specific SWAY Balance test results provided are of clinical use as references in the concussion assessments of pediatric athletes.

Changes of spatial and temporal characteristics of dynamic postural control in children with typical neurodevelopment with age: Results of a multicenter pediatric study

BACKGROUND

The aim of this multicenter study is to investigate the effect of chronological age and gender in postural control.

METHODS

To approach an ecological model, we used a multicenter posturography assessment. We analyzed postural control with surface, mean velocity of center of pressure [CoP] and temporal analysis, with Postural Instability Index [PII] being a more sensitive parameter in postural evaluation. A large sample of 156 age- and gender-matched healthy children recruited in several pediatrics hospitals, participated.

RESULTS

Our current results showed a significant decrease of all postural parameters (surface, mean velocity of CoP and PII) with age, and only on stable support condition. Our study additionally described a gender effect in conditions where all sensory inputs are most challenged with a mean velocity of CoP being significantly smaller in girls with respect to boys.

CONCLUSION

We concluded that postural control improves with age linked with maturation process. Moreover, this maturation process seems not yet achieved at 16.08 years and still ongoing beyond. Interestingly, our result reported specificities linked with gender effect. Indeed, girls and boys do not proceed in the same way to maintain their postural control. We could make hypothesis that more children maintain their postural control efficiently; with a low energy cost, the more they could allocate attention to learning during childhood.

Inertial Sensor Technology Can Capture Changes in Dynamic Balance Control during the Y Balance Test

Introduction

The Y Balance Test (YBT) is one of the most commonly utilised clinical dynamic balance assessments. Research has demonstrated the utility of the YBT in identifying balance deficits in individuals following lower limb injury. However, quantifying dynamic balance based on reach distances alone fails to provide potentially important information related to the quality of movement control and choice of movement strategy during the reaching action. The addition of an inertial sensor to capture more detailed motion data may allow for the inexpensive, accessible quantification of dynamic balance control during the YBT reach excursions. As such, the aim of this study was to compare baseline and fatigued dynamic balance control, using reach distances and 95EV (95% ellipsoid volume), and evaluate the ability of 95EV to capture alterations in dynamic balance control, which are not detected by YBT reach distances.

Methods

As part of this descriptive laboratory study, 15 healthy participants completed repeated YBTs at 20, 10, and 0 min prior to and following a modified 60-s Wingate test that was used to introduce a short-term reduction in dynamic balance capability. Dynamic balance was assessed using the standard normalised reach distance method, while dynamic balance control during the reach attempts was simultaneously measured by means of the 95EV derived from an inertial sensor, worn at the level of the 4th lumbar vertebra.

Results

Intraclass correlation coefficients for the inertial sensor-derived measures ranged from 0.76 to 0.92, demonstrating strong intrasession test-retest reliability. Statistically significant alterations (p < 0.05) in both reach distance and the inertial sensor-derived 95EV measure were observed immediately post-fatigue. However, reach distance deficits returned to baseline levels within 10 min, while 95EV remained significantly increased (p < 0.05) beyond 20 min for all 3 reach distances.

Conclusion

These findings demonstrate the ability of an inertial sensor-derived measure to quantify alterations in dynamic balance control, which are not captured by traditional reach distances alone. This suggests that the addition of an inertial sensor to the YBT may provide clinicians and researchers with an accessible means to capture subtle alterations in motor function in the clinical setting.