A Compound Hop Index for Assessing Soccer Players’ Performance

Athletes regularly have to pass a series of tests, among which one of the most frequently used functional performance measures are single-leg hop tests. As the collected individual results of tests constitute a large amount of data, strategies to decrease the amount of data without reducing the number of performed tests are being searched for. Therefore, the study aimed to present an effective method to reduce the hop-test battery data to a single score, namely, the Compound Hop Index (CHI) in the example of a soccer team. A male, first-league soccer team performed a battery of commonly used single-leg hop tests, including single hop and triple hop for distance tests and the six-meter timed hop test. Gathered data, including Limb Symmetry Indexes of the three tests, normalized to body height for the single- and triple-hop-tests distance separately for right and left legs, and the time of the six-meter timed hop test separately for right and left legs were standardized to z-scores. Consecutively, the z-scores were averaged and formed CHI. The developed CHI represents a novel score derived from the average of z-scores that significantly reduces, clarifies, and organizes the hop performance-measures data.

Sex Differences in the Relationship of Hip Strength and Functional Performance to Chronic Ankle Instability Scores

Background: Preliminary studies have reported differences in strength and functional performance between sexes for patients with anterior cruciate ligament injury or reconstruction. Similar sex differences may occur in chronic ankle instability (CAI) populations. Factors like hip abduction strength and functional performance may be contributors to sex differences in CAI populations, but their presence and magnitude is unclear. While decreased hip abductor strength, functional performance, and self-reported instability scores have all been shown in association with CAI, any sex difference in the relationship between these indicators is unclear. The study was to determine if sex differences are present in the relationship between these indicators in individuals with CAI.Methods：Thirty-two women and twenty-nine men with unilateral CAI took part. Hip abductor strength and functional performance were respectively assessed using a hand-held dynamometer and the figure-8-hop test. All 61 participants scored the Cumberland Ankle Instability Tool (CAIT) for self-reported ankle instability.Results: Normalized hip abductor strength and functional performance measures for females were lower than for males. The self-reported ankle instability CAIT score, where higher values represent less instability, was significantly and positively correlated with normalized hip abductor strength and functional performance on the affected side in females (all p < 0.01), but not in males (all p > 0.19).Conclusions: Sex differences were observed in the relationships of normalized hip abductor strength and functional performance to CAIT scores from the CAI, holding for females but not males, and suggesting that evaluation and rehabilitation strategies should be sex-specific.

DESEMPENHO DE ATLETAS PROFISSIONAIS DE FUTEBOL FEMININO NA EXECUÇÃO DOS TESTES STEP DOWN E SINGLE LEG HOP TEST

Introdução: As atletas profissionais de futebol são alvo de lesões musculoesqueléticas de forma proporcional a intensidade e ao nível de competitividade. Apresentam maior prevalência de lesões em membros inferiores, que estão relacionadas ao valgo de joelho. As avaliações através dos testes funcionais como o Step Down e o Single Leg Hop Test são um método importante para identificação do movimento que poderá interferir no desempenho das atletas durante os jogos. Objetivo: Avaliar o desempenho das atletas de futebol feminino durante a execução dos testes funcionais Step Down e Single Leg Hop Test. Métodos: O delineamento do estudo foi do tipo transversal. A amostra foi composta por 26 atletas de futebol feminino e foi caracterizada por uma ficha de caracterização da amostra. A avaliação funcional realizada pelo índice de simetria nos testes Single Hop Test e Step Down. Resultados: As atletas tinham idade média 21,38 (±3,82), praticavam o esporte a 10 (±5,02) anos e treinavam 2 (±1) horas por dia ao longo de 6 (±2) dias da semana, (57,7%) apresentam histórico de lesão relacionada ao esporte. Não houve diferença estatisticamente significante entre o membro dominante e não dominante para a distância média (p=0,773) e normalizada (p=0,678) no Single Leg Hop Test. Não foram encontradas diferenças estatisticamente significantes entre o membro dominante e não dominante quanto ao grau das alterações para a queda da pelve (p=0,442) e adução do quadril (p=0,390) no Step Down Test. Conclusão: As atletas obtiveram bom desempenho com ISM no Single Leg Hop Test e baixo desempenho no Step Down pelas alterações de equilíbrio em queda pélvica e adução de joelho. Não houve diferença significativa na melhora do desempenho em relação dominância de membros inferiores em ambos os testes. Palavras-chave: Futebol. Mulheres. Fisioterapia. Traumatismos em Atletas.

RELAÇÃO ENTRE OS FATORES DE RISCO PARA LESÃO EM ATLETAS DE FUTSAL MASCULINO

O objetivo desse estudo foi analisar possíveis fatores de risco para lesão em atletas de futsal masculino. Esse estudo transversal incluiu 15 atletas de futsal masculino (21,80±3,21 anos), sendo submetidos aos seguintes testes funcionais: a) avaliação da função dos músculos extensores do quadril (Single leg bridge test); b) avaliação da função lombopélvica/CORE (Prone bridge test); c) avaliação do desempenho funcional de membros inferiores (single hop test, timed hop test e side hop test); d) avaliação da amplitude de movimento (ADM) de dorsiflexão do tornozelo (teste de Lunge). Como resultados, a maior parte dos atletas apresentaram alto risco em relação à função muscular de extensores de quadril, em ambos os lados (53,3%), assim como déficit na função lombopélvica/CORE (66,7%), além de déficits em relação ao desempenho funcional de ambos os membros inferiores (57,14%). Os atletas apresentaram importantes fatores de risco para lesões, e sugere-se a relevância da construção de ações preventivas nesse contexto.

Symmetry in Triple Hop Distance Hides Asymmetries in Knee Function After ACL Reconstruction in Athletes at Return to Sports

Background: After anterior cruciate ligament reconstruction (ACLR), a battery of strength and hop tests is frequently used to determine the readiness of an athlete to successfully return to sports. However, the anterior cruciate ligament reinjury rate remains alarmingly high. Purpose: To evaluate the lower limb function of athletes after ACLR at the time when they had been cleared to return to sports (RTS). We aimed to evaluate if passing discharge criteria ensures restoration of normal lower limb biomechanics in terms of kinematics, kinetics, work, and percentage work contribution during a triple hop for distance. Study Design: Controlled laboratory study. Methods: Integrated 3-dimensional motion analysis was performed in 24 male athletes after ACLR when cleared to RTS and 23 healthy male controls during the triple-hop test. The criteria for RTS were (1) clearance by the surgeon and the physical therapist, (2) completion of a sports-specific on-field rehabilitation program, and (3) limb symmetry index >90% after quadriceps strength and hop battery tests. Lower limb and trunk kinematics, as well as knee joint moments and work, were calculated. Between-limb differences (within athletes after ACLR) and between-group differences (between ACLR and control groups) were evaluated using mixed linear models. Results: Although achieving 97% limb symmetry in distance hopped and displaying almost 80% symmetry for knee work absorption in the second rebound and third landing, the ACLR cohorts demonstrated only 51% and 66% limb symmetry for knee work generation in the first and second rebound phases, respectively. During both work generation phases of the triple hop, the relative contribution of the involved knee was significantly smaller, with a prominent compensation from the hip joint ( P < .001, for all phases) as compared with the uninvolved limb and the controls. In addition, patients deployed a whole body compensatory strategy to account for the between-limb differences in knee function, mainly at the hip, pelvis, and trunk. Conclusion: Symmetry in the triple hop for distance masked important deficits in the knee joint work. These differences were more prominent during work generation (concentric-propulsive) than work absorption (eccentric-landing). Clinical Relevance: Symmetry in hop distance during the triple hop test masked significant asymmetries in knee function after ACLR and might not be the appropriate outcome to use as a discharge criterion. Differences between limbs in athletes after ACLR were more prominent during the power generation than the absorption phase.

No Relationship between Lean Mass and Functional Asymmetry in High-Level Female Tennis Players

The relationship between lean mass and functional asymmetry in terms of their magnitude and direction was examined in 22 high-level female tennis players (20.9 ± 3.6 years). Lean mass of both upper and lower extremities was examined using Dual X-ray Absorptiometry. Functional asymmetry was assessed using a battery of field tests (handgrip strength, seated shot-put throw, plate tapping, single leg countermovement jump, single leg forward hop test, 6 m single leg hop test, and 505 change of direction (time and deficit)). Paired sample t-tests compared the dominant (overall highest/best (performance) value) against the non-dominant value (highest/best (performance) value of the opposing extremity). Linear regressions were used to explore the relationship between lean mass and functional asymmetry magnitudes. Kappa coefficients were used to examine the consistency in direction between the extremity displaying the highest lean mass value and the extremity performing dominantly across tests. Significant asymmetry magnitudes (p < 0.05) were found for all upper and lower extremity lean mass and functional values. No relationship was apparent between lean mass and functional asymmetry magnitudes (p-value range = 0.131–0.889). Despite finding perfect consistency in asymmetry direction (k-value = 1.00) for the upper extremity, poor to fair consistency (k-value range = −0.00–0.21) was found for the lower extremity. In conclusion, lean mass and functional asymmetries should be examined independently.

Recovery After ACL Reconstruction in Male Versus Female Adolescents: A Matched, Sex-Based Cohort Analysis of 543 Patients

Background: Differences in postoperative recovery after anterior cruciate ligament reconstruction (ACLR) between men and women have been demonstrated in the adult population. Sex-based differences have been incompletely investigated in adolescents, which represent the subpopulation most affected by ACL injury. Purpose/Hypothesis: The purpose of this study was to compare the 6-month postoperative functional recovery after ACLR between adolescent boys and girls. It was hypothesized that significant differences in postoperative strength, dynamic balance, and functional hop test performance would be seen between the sexes. Study Design: Cohort study; Level of evidence, 3. Methods: Included in this study were athletes aged 12 to 19 years with closed or closing growth plates who underwent ACLR with hamstring autograft between May 2014 and May 2018 at a single institution. All athletes had undergone strength and functional testing between 5 and 8 months postoperatively. Exclusion criteria were previous knee surgery (contralateral or ipsilateral knee), concomitant injury/surgery other than meniscal tear/repair, allograft supplementation, and incomplete medical records. The limb symmetry index (LSI) for strength (measured with handheld dynamometer), as well as dynamic Y-balance and functional hop test performance, was compared between groups. To account for differences in physical characteristics between the sexes, 1-way between-group multivariate analysis of covariance was used to analyze the data. Results: Overall, 543 patients (211 boys, 332 girls) were included. There was no significant difference in age, body mass index, incidence of concomitant meniscal pathology, use of regional anesthesia, or time to functional testing between cohorts. Female athletes demonstrated a statistically significantly greater deficit in quadriceps strength LSI compared with male athletes (boys, +3.4%; girls, –2.3%; P = .011). Both male and female athletes demonstrated 33% hamstring strength deficits, with no statistically significant sex-based differences in dynamic balance or functional hop testing. Conclusion: Female athletes demonstrated greater quadriceps strength deficits than male athletes at 6 months after ACLR with hamstring autograft. Severe hamstring strength deficits persisted in both male and female patients at this time point. The correlation of such deficits to risk of ACL retear warrants continued study in the adolescent population and may support a delay in return to sports, which has been suggested in the more recent literature.

Hip Abductor and Adductor Rate of Torque Development and Muscle Activation, but Not Muscle Size, Are Associated With Functional Performance

Understanding the physiological variables that contribute to a functional task provides important information for trainers and clinicians to improve functional performance. The hip abductors and adductors muscles appear to be important in determining the performance of some functional tasks; however, little is known about the relationship of the hip abductor/adductors muscle strength, activation, and size with functional performance. This study aimed to investigate the relationship of maximum torque, rate of torque development (RTD), rate of activation (RoA), and muscle thickness of the hip abductors [tensor fascia latae (TFL) and gluteus medius (GM)] and adductor magnus muscle with the Four Square Step Test (FSST) and the two-leg hop test in healthy young adults. Twenty participants (five males) attended one testing session that involved ultrasound image acquisition, maximal isometric voluntary contractions (hip abduction and hip adduction) while surface electromyography (EMG) was recorded, and two functional tests (FSST and two-leg side hop test). Bivariate correlations were performed between maximum voluntary torque (MVT), RTD at 50, 100, 200, and 300ms, RoA at 0–50, 0–100, 0–200, and 0–300, and muscle thickness with the dynamic stability tests. For the hip abduction, MVT (r=−0.455, p=0.044) and RTD300 (r=−0.494, p=0.027) was correlated with the FSST. GM RoA50 (r=−0.481, p=0.032) and RoA100 (r=−0.459, p=0.042) were significantly correlated with the two-leg side hop test. For the hip adduction, there was a significant correlation between the FSST and RTD300 (r=−0.500, p=0.025), while the two-leg side hop test was correlated with RTD200 (r=0.446, p=0.049) and RTD300 (r=0.594, p=0.006). Overall, the ability of the hip abductor and adductor muscles to produce torque quickly, GM rapid activation, and hip abductor MVT is important for better performance on the FSST and two-leg hop tests. However, muscle size appears not to influence the same tests.