Local experience of laboratory activities in a BS physical therapy course: integrating sEMG and kinematics technology with active learning across six cohorts.

Introduction: Integrating technology and active learning methods into Laboratory activities would be a transformative educational experience to familiarize physical therapy (PT) students with STEM backgrounds and STEM-based new technologies. However, PT students struggle with technology and feel comfortable memorizing under expositive lectures. Thus, we described the difficulties, uncertainties, and advances observed by faculties on students and the perceptions about learning, satisfaction, and grades of students after implementing laboratory activities in a PT undergraduate course, which integrated surface-electromyography (sEMG) and kinematic technology combined with active learning methods. Methods: Six cohorts of PT students (n = 482) of a second-year PT course were included. The course had expositive lectures and seven laboratory activities. Students interpreted the evidence and addressed different motor control problems related to daily life movements. The difficulties, uncertainties, and advances observed by faculties on students, as well as the students' perceptions about learning, satisfaction with the course activities, and grades of students, were described. Results: The number of students indicating that the methodology was "always" or "almost always," promoting creative, analytical, or critical thinking was 70.5% [61.0-88.0%]. Satisfaction with the whole course was 97.0% [93.0-98.0%]. Laboratory grades were linearly associated to course grades with a regression coefficient of 0.53 and 0.43 R-squared (p < 0.001). Conclusion: Integrating sEMG and kinematics technology with active learning into laboratory activities enhances students' engagement and understanding of human movement. This approach holds promises to improve teaching-learning processes, which were observed consistently across the cohorts of students.

Simultaneous in-air and underwater 3D kinematic analysis of swimmers: Feasibility and reliability of action sport cameras.

This study explored the potential of reconstructing the 3D motion of a swimmer's hands with accuracy and consistency using action sport cameras (ASC) distributed in-air and underwater. To record at least two stroke cycles of an athlete performing a front crawl task, the cameras were properly calibrated to cover an acquisition volume of 3 m in X, 8 m in Y, and 3.5 m in Z axis, approximately. Camera calibration was attained by applying bundle adjustment in both environments. A testing wand, carrying two markers, was acquired to evaluate the three-dimensional (3D) reconstruction accuracy in-air, underwater, and over the water transition. The global 3D accuracy (mean absolute error) was less than 1.5 mm. The standard error of measurement and the coefficient of variation were smaller than 1 mm and 1%, respectively, revealing that the camera calibration procedure was highly repeatable. No significant correlation between the error magnitude (percentage error during the test and the retest sessions: 1.2 to 0.8%) and the transition from in-air to underwater was observed. The feasibility of the hand motion reconstruction was demonstrated by recording five swimmers during the front crawl stroke, in three different tasks performed at increasing efforts. Intra-class correlation confirmed the optimal agreement (ICC>0.90) among repeated stroke cycles of the same swimmer, irrespective of task effort. Skewness, close to 0, and kurtosis, close to 3.5, supported the hypothesis of negligible effects of the calibration and tracking errors on the motion and speed patterns. In conclusion, we may argue that ASCs, equipped with a robust bundle adjustment camera calibration technique, ensure reliable reconstruction of swimming motion in in-air and underwater large volumes.

Effects of triceps surae exercise-induced delayed onset muscle soreness on control of body stability in different postures.

This research aimed to determine whether triceps surae delayed onset muscle soreness (DOMS) affects stability while performing different postural control tasks requiring upright and landing stabilization. Twenty-four participants who self-reported as healthy were recruited. Pre and 48 h after a protocol to induce DOMS in the triceps surae, participants were evaluated for DOMS perception, pressure pain threshold, and postural control (assessed by the center of pressure, CoP) during different standing and landing stabilization tasks. We found higher DOMS perception and lower pressure pain threshold 48 h after the exercise. Mediolateral CoP displacement was more sensitive to DOMS across different postural tasks, but no effects were found for bilateral standing. The landing time to stabilization elicited high individual variability in the presence of DOMS. Effects of DOMS in the performance of less challenging tasks, such as bipedal standing, were not found. We conclude that DOMS in the triceps surae impairs mediolateral postural control during challenging tasks such as unilateral standing and body forward lean. It highlights the need for caution and individualized approaches when incorporating movements requiring frontal plane control in training and rehabilitation sessions under the presence of DOMS.

Effects of Resistance Training of Upper Limb and Trunk Muscles on Soccer Instep Kick Kinematics.

The upper body and trunk muscles are crucial to perform soccer kicks. Resistance training targeting these muscles may modify the pattern adopted during kicking. This study aimed to investigate the effect of resistance training of the arm and anterior trunk muscles on instep kicking kinematics. Twenty-six male participants were randomly allocated into a training group or control group. The training group underwent resistance training of arm and trunk muscles and practiced the instep kick for 8 weeks. The control group only practiced kicking during the same period. The trunk, hip, and knee kinematics were assessed during the instep kick before and after the intervention. Kinematics were analyzed according to their data distribution with statistical parametric or nonparametric mapping. The effect of the training on the 1-repetition maximum test was analyzed using a repeated-measures multivariate analysis of variance. The training group showed greater hip extension after the training during the backswing phase (Hedge g effect size of 0.316-0.321) and increased 1-repetition maximum for all exercises. There were no other differences. The present study documented the nonlocal effect of strengthening training in which arm and trunk muscle training resulted in changes in hip kinematics during the backswing phase of the instep kick.

Overweight Impairs Postural Control of Female Night Workers.

Objectives To verify the relationships between sleep duration (Total Sleep Time - TST) and postural control of female night workers before and after shift. As well as, to verify if there is an influence of the body mass index (BMI) on the postural control of these female workers before and after shift. Methods A total of 14 female night workers (mean age: 35.0 ± 7.7 years) were evaluated. An actigraph was placed on the wrist to evaluate the sleep-wake cycle. The body mass and height were measured, and BMI was calculated. Postural control was evaluated by means of a force platform, with eyes opened and eyes closed before and after the 12-hour workday. Results There was an effect of the BMI on the velocity and the center of pressure path with eyes opened before ( t = 2.55, p = 0.02) and after ( t = 4.10, p < 0.01) night work. The BMI impaired the velocity and the center of pressure path with eyes closed before ( t = 3.05, p = 0.01; t = 3.04, p = 0.01) and after ( t = 2.95, p = 0.01; t = 2.94, p = 0.01) night work. Furthermore, high BMI is associated with female workers' postural sway ( p < 0.05). Conclusion Therefore, high BMI impairs the postural control of female night workers, indicating postural instability before and after night work.

Physical Activity Levels and Psychological Well-Being during COVID-19 Lockdown among University Students and Employees.

During the lockdown for the coronavirus disease 2019 (COVID-19), entire populations were instructed to live in home confinement. We investigated the effects of the COVID-19 lockdown on the physical activity (PA) and mental health of students and employees in a Colombian University. A cross-sectional study was conducted through an online survey during the first isolation. A total of 431 respondents (192 males) aged 18-60 years old (28.1 ± 11.1 years) participated. The international Physical Activity Questionnaire (IPAQ) and the short version of the Psychological General Well-Being Index (PGWBI-S) were used. The lockdown had a negative effect on PA levels, with students exhibiting the greatest decrease (~34%; p ˂ 0.001) compared to employees (~24%; p ˂ 0.01). The analysis showed a greater change in PA behavior before and during the lockdown in highly active student participants (5750 vs. 5141 MET min/week; p < 0.05). Additionally, the psychological assessment revealed a lower score in students compared to employees in the male (70.1 vs. 82.6) and female groups (60.2 vs. 79.6). Moreover, the results revealed an influence of sex, with only the female students exhibiting a state of distress. Self-reported PA and psychological well-being were compromised during the COVID-19 lockdown in the academic community, with students and females being more affected.

Small-Sided Soccer Games with Larger Relative Areas Result in Higher Physical and Physiological Responses: a Systematic and Meta-Analytical Review.

This study aimed to systematically review the influence of the relative area on athletes' physical and physiological responses (outcomes) during small-sided games of soccer which were not matched to the relative area. It also presents a meta-analysis comparing standard small-sided games protocols with different relative areas. We searched the Web of Science and Scopus electronic databases for literature published up to March 2020 following all PRISMA guidelines for selecting articles for a qualitative and quantitative synthesis. As a result, eleven articles matched the inclusion criteria. For the quantitative synthesis, a pooled random-effects model was used to make pairwise comparisons between protocols with larger or smaller areas in each selected study. Prediction intervals were used to assess the heterogeneity. We found positive effects of larger relative areas per player on their total distance (d = 0.73; 95% CI = 0.12-1.34; p = 0.006; medium to large effect), distance covered at high speed (d = 0.93; 95% CI = 0.22-1.65; p = 0.001; large effect), and mean heart rate (d = 0.52; 95% CI = 0.17-0.88; p = 0.008; medium effect). In other words, larger relative areas were found to induce higher physical and physiological responses in players. Future studies should consider the relative area per player when comparing data for different small-sided games configurations to avoid confounding variables. Also, coaches can use relative area per player calculations to easily predict increases and decreases in expected training loads for different versions of SSGs during training.

Progression to the target vs. regular rules in Soccer small-sided Games.

BACKGROUND: This study compared the physical, physiological, and spatiotemporal responses of soccer athletes in small-sided games (SSG) in two experimental conditions: progression to the target rule (PG), in which they should take the ball to the opponent's endline to score points, and SSG with regular rules (RG), in which they should score goals to win the game. METHODS: Twenty U-20 athletes played both SSG formats. The SSG were played as four 4-minute bouts with four minutes of passive recovery in two consecutive days. Heart rate, physical (distances and accelerations), and positional data (length, width, and spatial exploration) were collected by a 10 hz GPS device and compared between the protocols using a MANOVA with Bonferroni's correction for multiple comparisons. RESULTS: Results showed that the RG condition demanded more spatial exploration eliciting greater occupation of the pitch width. There were higher mean and maximum heart rates and greater low-to-moderate distances and accelerations in the RG, while the PG rule increased the distances covered at the highest speed and acceleration zones. CONCLUSIONS: The progression to the target rule should be adopted to emphasize players' ability to use the width during the offensive phase. Additionally, the PG rule should also be used to emphasize the development of speed and acceleration skills.

Trajectories of pain and disability in older adults with acute low back pain: Longitudinal data of the BACE-Brazil cohort.

BACKGROUND: Although the literature describes a favorable course of low back pain (LBP) in adults, little information is available for older adults. LBP is prevalent and complex in older adults, and the analysis of its trajectories may contribute to the improvement of therapeutic approaches. OBJECTIVE: To describe pain and disability trajectories in older adults with a new episode of LBP. METHODS: Older adults (n = 542), aged >55 years with a new episode of nonspecific LBP, were followed for 12 months in a prospective cohort. Pain intensity (Numeric Rating Scale) and disability (Roland-Morris Disability Questionnaire) were assessed at baseline and 3, 6, 9, and 12 months. Latent class growth analysis (LCGA) was used to model pain and disability scores over time. Baseline biopsychosocial characteristics were compared using one-way analysis of variance or Chi-square test (α=0.05). RESULTS: The LCGA identified three and four trajectories in the pain and disability courses, respectively. Trajectories with low, intermediate, or high scores over time were defined. Worse biopsychosocial status at baseline was associated with worst prognosis over 12 months. Low educational level, physical inactivity, poor mobility, recent falls, worse fall self-efficacy, presence of depressive symptoms, more kinesiophobia, greater number of comorbidities, and the presence of other LBP-associated complaints were found in older adults with severe and persistent symptoms. CONCLUSION: The trajectories allow the identification of clusters with similar clinical prognoses in older adults with a new episode of LPB. In practice, excessive treatments and unnecessary tests can be avoided, while more accurate and targeted interventions can be implemented.

Characterizing the magnitude of vibration imposed by stochastic whole-body vibration platforms used in rehabilitation and training: a preliminary study / Caracterização da magnitude da vibração imposta por plataformas vibratórias estocásticas de corpo inteiro utilizadas em reabilitação e treinamento: estudo preliminar

Abstract The use of devices that produce stochastic whole-body vibration as a resource for rehabilitation and training programs has been founded on the theory of stochastic resonance. However, the prescription of rehabilitation and training programs must be preceded by the verification of imposed-vibration magnitude and of how it can be affected by the presence of an individual on the devices. The aim of this research was to characterize and analyze the effect of an individual's mass on the vibratory stimulus provided by stochastic whole-body vibration (SWBV) devices. The sample consisted of 30 repetitions for each one of the 6 vibration levels of the SWBV device (level 02, 04, 06, 08, 10 and 12), performed in two experimental situations (Without Load; Load [70Kg]; ≈ 35 kg on the right and left surfaces of the platform). For the antero-posterior, latero-lateral, and vertical directions, all variables showed significant differences between treatments, levels and interaction between experimental factors (p<.05), except for the Disp variable between treatments (p=.075). To measure vibration magnitude, a triaxial accelerometer was attached at the center of the board of one of the platform surfaces. Load interferes with parameters of vibration imposed by SWBV platforms, increasing ARMS and APEAK in the latero-lateral and antero-posterior directions, reducing these same parameters in the vertical direction.

Resumo O uso de dispositivos que produzem vibração estocástica de corpo inteiro como recurso para programas de reabilitação e treinamento foi fundamentado na teoria da ressonância estocástica. Entretanto, a prescrição de programas de reabilitação e treinamento deve ser precedida da verificação da magnitude da vibração imposta e de como ela pode ser afetada pela presença de um indivíduo nos dispositivos. O objetivo deste estudo foi caracterizar e analisar o efeito da massa do indivíduo sobre o estímulo vibratório proporcionado por dispositivos de vibração estocástica de corpo inteiro. A amostra consistiu em 30 repetições para cada um dos 6 níveis de vibração de um dispositivo de vibração estocástica de corpo inteiro (nível 02, 04, 06, 08, 10 e 12), realizados em duas situações experimentais (Sem carga e Carga [70Kg], 35 kg nas superfícies direita e esquerda da plataforma). Para medir a magnitude da vibração, um acelerômetro triaxial foi fixado ao centro do assoalho de uma das superfícies da plataforma. Para os eixos ântero-posterior, látero-lateral e vertical, todas as variáveis mostraram diferenças entre tratamentos, níveis e interação entre fatores experimentais (p<.05), exceto para a variável de deslocamento pico - a - pico (Disp) entre tratamentos (p=.075). A carga interfere com parâmetros de vibração impostos sobre as plataformas de vibração estocástica de corpo inteiro, aumentando a aceleração média (ARMS) e de pico (APEAK) nas direções látero-lateral e ântero-posterior, reduzindo estes mesmos parâmetros na direção vertical.

Associations between Physical Status and Training Load in Women Soccer Players.

This study aimed to analyze the variations of fitness status, as well as test the relationships between accumulated training load and fitness changes in women soccer players. This study followed an observational analytic cohort design. Observations were conducted over 23 consecutive weeks (from the preseason to the midseason). Twenty-two women soccer players from the same first Portuguese league team (22.7 ± 5.21 years old) took part in the study. The fitness assessment included anthropometry, hip adductor and abductor strength, vertical jump, change of direction, linear speed, repeated sprint ability, and the Yo-Yo intermittent recovery test. The training load was monitored daily using session rating of perceived exertion (s-RPE). A one-way repeated ANOVA revealed no significant differences for any of the variables analyzed across the three moments of fitness assessments (p > 0.05). The t-test also revealed no differences in the training load across the moments of the season (t = 1.216; p = 0.235). No significant correlations were found between fitness levels and accumulated training load (range: r = 0.023 to -0.447; p > 0.05). This study revealed no differences in the fitness status during the analyzed season, and the fitness status had no significant relationship with accumulated training load.

Biomechanics without Borders: Teaching Biomechanics in Brazil and South Africa.

The "Biomechanics without Borders: Teaching Biomechanics in Brazil and South Africa" involved academics from different countries combining efforts to improve remote education. In addition to the live discussions, the event resulted in the availability of online content to help academic staffs improve teaching strategies in the field of human movement sciences.

The influence of the offside rule on players' positional dynamics in soccer small-sided games.

BACKGROUND: Previous studies on soccer small-sided games (SSGs) chose between with and without offside rule conditions without evidence-based criteria. The current study aimed to compare the positional dynamics of 3v3 SSGs with and without the offside rule. METHODS: Twenty-four Brazilian U-17 national-level soccer players were recruited. They were split into eight teams and played SSGs with and without the offside rule . Positional data were gathered by a Global Positioning System, and teams' length, width, the length per width ratio (LPWratio), stretch index and players' spatial exploration index were calculated. Data were compared between the experimental conditions by a paired t-test. RESULTS: Results showed that SSGs with the offside rule presented lower values of length (~16.63%, large effect), the LPWratio (~19.74%, large effect), and players' spatial exploration (~4.13%, small-to-moderate effect). CONCLUSION: We conclude that the offside rule impacts players' positional behavior in SSGs, inducing a less exploratory behavior mainly in the width axis. For this reason, we recommend caution when interpreting previous results on SSG when the offside rule was not applied since adopting this rule might elicit different responses to the players . Coaches can manipulate this rule aiming to achieve specific tactical goals for the training session.

TDCS of the Primary Motor Cortex: Learning the Absolute Dimension of a Complex Motor Task.

The primary motor cortex (M1) is one of the main cortical areas involved in motor learning. However, little is known about its differential role in the learning of the relative and absolute dimensions of motor skills. We investigated the role of M1 in the learning of the dimensions of a complex motor skill. Forty-eight participants practiced golf putting and were stimulated for 20 minutes with real or sham bihemispheric tDCS before acquisition. tDCS improved global performance from pre- to post-test. Only those with worse initial performance who were stimulated by tDCS showed a significant improvement in the skill's absolute dimension. No effects of tDCS were found for the relative dimension. Our results suggest that M1 has a distinct participation in the learning of the absolute dimension of complex motor skills, and tDCS effects are influenced by the learner's level of initial performance.

Prediction equation of hip external rotators maximum torque in healthy adults and older adults using the measure of hip extensors maximum torque.

BACKGROUND: The use of predictive equation of muscular torque can reduce physical effort and time spent during evaluation. OBJECTIVES: To establish, validate, and test the accuracy of a prediction equation to estimate the hip external rotators (HER) torque in adults and older adults by means of hip extensors (HEX) torque measurement. METHODS: Eighty-three healthy adults (development set) were assessed to test the association of HEX and HER torques and to establish the prediction equation. A separate 36 adults and 15 older adults (validation sets) were assessed to test the ability of the equation to estimate HER torque. Hip isometric strength was assessed by a handheld dynamometer. RESULTS: Simple linear regression analysis revealed that HEX torque was associated with HER torque (r=0.80; p<0.0001), resulting in the following prediction equation: HERtorque=-0.02+(0.58 * HEXtorque). Paired t-test revealed no difference between directly measured and predicted values of HER torque in adults (mean difference=0.02; 95% CI=-0.115, 0.072) and older adults (mean difference=0.05; 95% CI=-0.02, 0.12). CONCLUSION: The HEX and HER torques were strongly correlated. The prediction equation was valid, accurate, and can be used to estimate HER muscle strength in healthy adults and older adults, requiring only the direct measurement of HEX torque.

Prevalence and incidence of injuries in para athletes: a systematic review with meta-analysis and GRADE recommendations.

OBJECTIVE: To investigate prevalence, incidence and profile of musculoskeletal injuries in para athletes. DESIGN: Systematic review. DATA SOURCES: Searches were conducted in MEDLINE, EMBASE, AMED, SPORTSDiscus, CINAHL and hand searching. ELIGIBILITY CRITERIA: Studies were considered if they reported prevalence or incidence of musculoskeletal injuries in para athletes. Study selection, data extraction and analysis followed the protocol. Meta-analyses were conducted to estimate the prevalence and incidence rate among studies and subgroup analyses investigated whether methodological quality and sample size of the studies influenced on the estimated injury prevalence and incidence. The Grading of Recommendations Assessment, Development and Evaluation system determined the strength of evidence. RESULTS: Forty-two studies were included. The prevalence of musculoskeletal injuries was 40.8% (95% CI 32.5% to 49.8%). Because of imprecision, indirectness and inconsistency, the strength of evidence was very low quality. The incidence of musculoskeletal injuries was 14.3 injuries per 1000 athlete-days (95% CI 11.9 to 16.8). The strength of evidence was low quality because of imprecision and indirectness. The subgroup analyses revealed that the sample size influenced on estimated injury prevalence and methodological quality influenced on estimated incidence. Injuries were more prevalent in the shoulder, for non-ambulant para athletes, and in the lower limbs, for ambulant para athletes. SUMMARY/CONCLUSION: Para athletes show high prevalence and incidence of musculoskeletal injuries. Current very low-quality and low-quality evidence suggests that future high-quality studies with systematic data collection, larger sample size and specificities of para athletes are likely to change estimates of injury prevalence and incidence in para athletes. PROSPERO REGISTRATION NUMBER: CRD42020147982.

Comparison of quadriceps muscle activation in exercises with different duration of concentric and eccentric contractions / Comparación de la activación muscular del cuádriceps en ejercicios con diferente duración de las contracciones concéntricas y excéntricas

AIM: The objective of the present study was to compare the amplitude of the electromyographic (EMG) signal of the quadriceps muscle portions vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) and the activation ratio (VM/VL, VM/RF and VL/RF) in protocols with different durations of concentric and eccentric muscular actions. MATERIAL AND METHOD: Twelve female volunteers performed the knee extensor exercise with two different protocols [1s for concentric muscle action and 5s for eccentric muscle action (1:5); 5s of concentric muscle action and 1s of eccentric muscle action (5:1)] and 3 sets of 6 repetitions, 180s of pause between each sets and a intensity of 50% of 1RM. The root mean square of the amplitude of the normalized EMG signal was calculated for each repetition in each series. RESULTS: it was observed an increase in the activation of the VM and VL portions in equivalent repetitions of each series and for the VL portion, the 1: 5 protocol provided greater activation compared to the other protocol. No differences were found for muscles activation ratios VM/RF and VL/RF, being that for the VM/VL ratio there was only change at one repetition. CONCLUSION: The results suggest that the portions of the quadriceps muscle may present different EMG responses in similar protocols, but this fact may not interfere in the synergism between them. The reduced degrees of freedom of the knee extension exercise and the characteristics of the protocols adopted may be the elements that contributed to the limited alterations that occurred in the present study

OBJETIVO: El objetivo del presente estudio fue comparar la amplitud de la señal electromiográfica (EMG) de las porciones de músculo cuádriceps vasto medial (VM), vasto lateral (VL) y recto femoral (RF) y la relación de activación (VM/VL, VM/RF y VL/RF) en protocolos con diferentes duraciones de acciones musculares concéntricas y excéntricas. MATERIAL Y MÉTODO: Doce mujeres voluntarias realizaron el ejercicio extensor de rodilla con dos protocolos diferentes [1 s para la acción muscular concéntrica y 5 s para la acción muscular excéntrica (1: 5); 5s de acción muscular concéntrica y 1s de acción muscular excéntrica (5: 1)] y 3 series de 6 repeticiones, 180s de pausa entre cada serie y una intensidad del 50% de 1RM. La raíz media cuadrática de la amplitud de la señal electromiográfica normalizada se calculó para cada repetición en cada serie. RESULTADOS: se observó un aumento en la EMG de las porciones de VM y VL en repeticiones equivalentes de cada serie y para la porción de VL, el protocolo 1: 5 proporcionó una mayor activación en comparación con el otro protocolo. No se encontraron diferencias para las relaciones de activación de los músculos VM/RF y VL/RF, siendo que para la relación VM/VL solo hubo cambios en una repetición. CONCLUSIÓN: Los resultados sugieren que las partes del músculo del cuádriceps pueden presentar diferentes respuestas de EMG en protocolos similares, pero este hecho puede no interferir en el sinergismo entre ellos. Los grados reducidos de libertad del ejercicio de extensión de la rodilla y las características de los protocolos adoptados pueden ser los elementos que contribuyeron a las alteraciones limitadas que se produjeron en el presente estudio

The Effects of Altering the Concentric/Eccentric Phase Times on EMG Response, Lactate Accumulation and Work Completed When Training to Failure.

This study compared the electromyographic response, the blood lactate concentration (BLC), and the maximum number of repetitions (MNR) between protocols of different concentric/eccentric duration taken to muscle failure. This comparison may help to understand how different concentric/eccentric duration may influence performance and the central and metabolic responses in trained men. Seventeen strength-trained men performed two protocols in a counterbalanced design. Three sets of the Smith bench press exercise were performed to failure at 60% of the one-repetition maximum (1RM) using each protocol (4-s concentric/2-s eccentric [4 s: 2 s]; and 2-s concentric/4-s eccentric [2 s: 4 s]). The normalized root mean square (EMGRMS) and the mean frequency (EMGMF) of the electromyographic signals for the pectoralis major and the triceps brachii were compared in the first, middle, and last repetitions. The BLC was assessed at rest, during and after the test sessions. To compare the EMG and BLC, a 3-way ANOVA with repeated measures with a post hoc Tukey's test was used. To compare the MNR performed across the sets, an ANOVA-type rank test with the Dunn's post hoc test was used. The ANOVA indicated a greater EMGRMS for Protocol 4 s: 2 s in the pectoralis major and a lower EMGMF for Protocol 4 s: 2 s in the triceps brachii at the middle and last repetitions. Both protocols increased the EMGRMS and decreased the EMGMF across repetitions. Despite the results show different levels of activation and neuromuscular fatigue between protocols, the BLC and the MNR were similar.

Correlation between running asymmetry, mechanical efficiency, and performance during a 10 km run.

Running asymmetry is considered a matter of concern for performance and injury, but the association between asymmetry and performance remain unclear. There are different strategies to address asymmetries and its relationship with performance. Here we investigated the correlation between global symmetry index and mechanical efficiency during 10 km running. Thirteen amateur trained athletes (8 men and 5 women) performed a 10 km running at a fixed pace while a 3D accelerometer attached to the pelvic region recorded position data throughout the course of the run and gas exchanges were monitored breath by breath. Global symmetry index was determined for 3 directions, and mechanical efficiency was calculated as the ratio of external work output to energy expenditure determined from gas analysis. Global Symmetry Index and mechanical efficiency decreased (-55.5% and -44.8%, respectively) during the course of the 10 km run (p < 0.01). A positive correlation was observed between global symmetry index and efficiency (r = 0.66, p = 0.01). Asymmetry in the vertical direction had a relatively higher impact on the global symmetry index. The global symmetry index accounted for 43.1% of the variance in mechanical efficiency (p = 0.015). Symmetry, evaluated by the global symmetry index, directly correlates with mechanical efficiency during a 10 km run.