Are Previous Joint Injuries Associated with Muscle Performance in Volleyball Athletes?

Objective The aim of the present study is to determine whether previous shoulder and knee injuries were associated with isokinetic fatigue index and agonist/antagonist ratio of shoulder internal/external rotators and knee flexors/extensors in male volleyball athletes. Methods The current study is a cross-sectional investigation of 49 male elite volleyball players competing at a high level in Brazil. Isokinetic fatigue index and agonist/antagonist profiles were assessed during the preseason. Additionally, in order to record previous injuries, the athletes answered a standardized questionnaire. We conducted a receiver operating characteristic (ROC) curve analysis to determine the association strength and the clinically relevant cut-off point for variables presenting statistical significance for the area under the curve (AUC) (α = 0.05). An independent t-test was used to compare isokinetic variables between athletes with and without previous injury (α = 0.05). Results The results of the ROC curve analysis indicated that hamstring fatigue index values at 300 o /s were associated with the presence of previous knee injury (area under the curve [AUC] = 73%, p = 0.004), and shoulder external rotators fatigue index values at 360°/s were not associated with the presence of previous shoulder injury (AUC = 68%, p = 0.053). Conclusions Elite volleyball athletes who reported previous knee injuries were prone to a higher fatigue index than those reporting no injuries. Knee flexor resistance training might be useful for those athletes who reported knee injuries in the previous season.

Are Previous Joint Injuries Associated with Muscle Performance in Volleyball Athletes? / Lesões articulares prévias são associadas ao desempenho muscular de jogadores de voleibol?

Abstract Objective The aim of the present study is to determine whether previous shoulder and knee injuries were associated with isokinetic fatigue index and agonist/antagonist ratio of shoulder internal/external rotators and knee flexors/extensors in male volleyball athletes. Methods The current study is a cross-sectional investigation of 49 male elite volleyball players competing at a high level in Brazil. Isokinetic fatigue index and agonist/antagonist profiles were assessed during the preseason. Additionally, in order to record previous injuries, the athletes answered a standardized questionnaire. We conducted a receiver operating characteristic (ROC) curve analysis to determine the association strength and the clinically relevant cut-off point for variables presenting statistical significance for the area under the curve (AUC) (α = 0.05). An independent t-test was used to compare isokinetic variables between athletes with and without previous injury (α = 0.05). Results The results of the ROC curve analysis indicated that hamstring fatigue index values at 300o/s were associated with the presence of previous knee injury (area under the curve [AUC] = 73%, p= 0.004), and shoulder external rotators fatigue index values at 360°/s were not associated with the presence of previous shoulder injury (AUC = 68%, p= 0.053). Conclusions Elite volleyball athletes who reported previous knee injuries were prone to a higher fatigue index than those reporting no injuries. Knee flexor resistance training might be useful for those athletes who reported knee injuries in the previous season.

Resumo Objetivo O objetivo deste estudo é determinar se lesões prévias de ombro e joelho estavam associadas ao índice de fadiga isocinética e razão agonista/antagonista dos rotadores internos/externos do ombro e flexores/extensores do joelho em jogadores de voleibol. Métodos Esta é uma investigação transversal com 49 jogadores de voleibol de elite que competem em alto nível no Brasil. O índice de fadiga isocinética e os perfis de agonistas/antagonistas foram avaliados durante a pré-temporada. Além disso, para registro de lesões anteriores, os atletas responderam a um questionário padronizado. Conduzimos uma análise da curva de característica de operação do receptor (receiver operating characteristic, ROC) para determinar a força de associação e o ponto de corte clinicamente relevante de variáveis com significância estatística na área sob a curva (AUC) (α = 0,05). Um teste t independente comparou as variáveis isocinéticas entre atletas com e sem lesão prévia (α = 0,05). Resultados Os resultados da análise da curva ROC indicam que os valores do índice de fadiga dos isquiotibiais a 300o/s foram associados à presença de lesão prévia no joelho (área soba a curva [AUC] = 73%, p= 0,004), enquanto os valores do índice de fadiga dos rotadores externos do ombro a 360°/s não foram associados à presença de lesão prévia no ombro (AUC = 68%, p= 0.053). Conclusões Atletas de voleibol de elite que relataram lesões anteriores no joelho estavam propensos a um índice de fadiga maior do que aqueles que não relataram lesões. O treinamento de resistência de flexores do joelho pode ser útil para atletas com relatos de lesões no joelho na temporada anterior.

Sports Injury Forecasting and Complexity: A Synergetic Approach.

The understanding that sports injury is the result of the interaction among many factors and that specific profiles could increase the risk of the occurrence of a given injury was a significant step in establishing programs for injury prevention. However, injury forecasting is far from being attained. To be able to estimate future states of a complex system (forecasting), it is necessary to understand its nature and comply with the methods usually used to analyze such a system. In this sense, sports injury forecasting must implement the concepts and tools used to study the behavior of self-organizing systems, since it is by self-organizing that systems (i.e., athletes) evolve and adapt (or not) to a constantly changing environment. Instead of concentrating on the identification of factors related to the injury occurrence (i.e., risk factors), a complex systems approach looks for the high-order variables (order parameters) that describe the macroscopic dynamic behavior of the athlete. The time evolution of this order parameter informs on the state of the athlete and may warn about upcoming events, such as injury. In this article, we describe the fundamental concepts related to complexity based on physical principles of self-organization and the consequence of accepting sports injury as a complex phenomenon. In the end, we will present the four steps necessary to formulate a synergetics approach based on self-organization and phase transition to sports injuries. Future studies based on this experimental paradigm may help sports professionals to forecast sports injuries occurrence.

Factors associated with the presence of patellar tendon abnormalities in male athletes.

OBJECTIVES: To investigate the association between lower limb alignment, range of motion/flexibility and muscle strength with the presence of patellar tendon abnormalities in male athletes. DESIGN: This was a cross-sectional study. METHODS: Thirty-one male basketball and volleyball athletes were assessed for ankle dorsiflexion range of motion, shank-forefoot alignment, iliotibial band flexibility, hip external rotators and abductors isometric torque, passive hip internal rotation range of motion and frontal plane knee and patellar alignment (McConnell and Arno angles). Ultrasonographic evaluations of hypoechoic areas of the patellar tendons were performed in longitudinal and transverse planes. A receiver operating characteristic curve was used to determine clinically relevant cut-off point for each variable. When the area under the curve was statistically significant, Prevalence Ratio (PR) and 95% confidence intervals were calculated to indicate the strength of the association between the independent variable and the presence of patellar tendon abnormalities. RESULTS: Receiver operating characteristic curve showed that iliotibial band flexibility (p=0.006), shank-forefoot alignment (p=0.013) and Arno angle (p=0.046) were associated with patellar tendon abnormalities. Cut-off points were established and only the Prevalence Ratio of iliotibial band flexibility (cut-off point=-0.02°/kg; PR=5.26) and shank-forefoot alignment (cut-off point=24°; PR=4.42) were statistically significant. CONCLUSIONS: Athletes with iliotibial band or shank-forefoot alignment above the clinically relevant cut-off point had more chance to have patellar tendon abnormalities compared to athletes under the cut-off point values. These results suggest that such factors could contribute to patellar tendon overload, since patellar tendon abnormalities indicate some level of tissue damage. Both factors might be considered in future prospective studies.

Foot and hip contributions to high frontal plane knee projection angle in athletes: a classification and regression tree approach.

STUDY DESIGN: Cross-sectional. OBJECTIVE: To investigate predictors of increased frontal plane knee projection angle (FPKPA) in athletes. BACKGROUND: The underlying mechanisms that lead to increased FPKPA are likely multifactorial and depend on how the musculoskeletal system adapts to the possible interactions between its distal and proximal segments. Bivariate and linear analyses traditionally employed to analyze the occurrence of increased FPKPA are not sufficiently robust to capture complex relationships among predictors. The investigation of nonlinear interactions among biomechanical factors is necessary to further our understanding of the interdependence of lower-limb segments and resultant dynamic knee alignment. METHODS: The FPKPA was assessed in 101 athletes during a single-leg squat and in 72 athletes at the moment of landing from a jump. The investigated predictors were sex, hip abductor isometric torque, passive range of motion (ROM) of hip internal rotation (IR), and shank-forefoot alignment. Classification and regression trees were used to investigate nonlinear interactions among predictors and their influence on the occurrence of increased FPKPA. RESULTS: During single-leg squatting, the occurrence of high FPKPA was predicted by the interaction between hip abductor isometric torque and passive hip IR ROM. At the moment of landing, the shank-forefoot alignment, abductor isometric torque, and passive hip IR ROM were predictors of high FPKPA. In addition, the classification and regression trees established cutoff points that could be used in clinical practice to identify athletes who are at potential risk for excessive FPKPA. CONCLUSION: The models captured nonlinear interactions between hip abductor isometric torque, passive hip IR ROM, and shank-forefoot alignment.

Reliability of transverse plane pelvic alignment measurement during the bridge test with unilateral knee extension.

BACKGROUND: The bridge test with unilateral knee extension evaluates the stability of the trunk and pelvis. The evaluation of this stability can contribute to the understanding of the occurrence of musculoskeletal injuries. OBJECTIVES: To investigate the intra- and inter-rater reliability of a qualitative analysis and intra-test reliability of a quantitative analysis of transverse plane pelvic alignment during the bridge test with unilateral knee extension. METHOD: Thirty participants (24.73±4.24 years old) were tested. The qualitative analysis was conducted by asking two raters to judge the transverse plane pelvic alignment and its reliability was assessed with the weighted kappa coefficient (k(w)). The quantitative analysis was conducted by measuring the greatest pelvic tilt angle in transverse plane and its reliability was assessed by use of the intraclass correlation coefficient (ICC); the mean change, which was evaluated using 95% confidence interval of the mean difference (95%CI d) and Bland-Altman plot; and the quantification of measurement variability, which was assessed using standard error of measurement (SEM) and the coefficient of variation of the typical error (CVTE). In addition, the minimal detectable change (MDC95) was determined. RESULTS: The intra-rater reliability ranged from fair to moderate (k(w)=0.32 to 0.58) and the inter-rater reliability was substantial (k(w)=0.80). The intra-test reliability was excellent (ICC=0.82), the 95%CI d ranged from -0.51º to 1.99º, the SEM was 2.38° and the CV(TE) was 28.75%. The MDC95 was 6.59°. CONCLUSIONS: The inter-rater reliability was greater than the intra-rater reliability; the intra-test reliability was excellent and showed no systematic or random error.

Confiabilidade da mensuração do alinhamento pélvico no plano transverso durante o teste da ponte com extensão unilateral do joelho / Reliability of transverse plane pelvic alignment measurement during the bridge test with unilateral knee extension

CONTEXTUALIZAÇÃO: O teste da ponte com extensão unilateral do joelho avalia a estabilidade de tronco e pelve. A avaliação dessa estabilidade pode contribuir para o entendimento da ocorrência de lesões musculoesqueléticas. OBJETIVOS: Investigar a confiabilidade intra e interexaminador de uma análise qualitativa e a confiabilidade intrateste de uma análise quantitativa do alinhamento pélvico no plano transverso durante o teste da ponte com extensão unilateral do joelho. MÉTODO: Foram avaliados 30 participantes (24,73±4,24 anos). A análise qualitativa foi realizada pelo julgamento do alinhamento pélvico no plano transverso por dois examinadores, e sua confiabilidade determinada pelo Coeficiente Kappa Ponderado (k w). A análise quantitativa foi realizada pela medida do maior ângulo de desalinhamento pélvico no plano transverso e a confiabilidade determinada pelo Coeficiente de Correlação Intraclasse (CCI); pela análise da mudança na média dos dados, utilizando-se o intervalo de confiança de 95% da média da diferença (95%IC ) e método de Bland-Altman; pelo dimensionamento da variabilidade entre medidas, considerando-se o erro-padrão da medida combinado (EPM) e coeficiente de variação do erro típico (CV ET). Além disso, verificou-se a mudança mínima detectável (MMD95). RESULTADOS: A confiabilidade intraexaminador variou de razoável a moderada (k w=0,32-0,58) e a confiabilidade interexaminador foi substancial (k w=0,80). A confiabilidade intrateste foi excelente (CCI=0,82) e apresentou o IC95% de -0,51º a 1,99º, EPM de 2,38º e o CV ET de 28,75%. O MMD95 foi de 6,59º. CONCLUSÕES: O índice de confiabilidade interexaminador foi superior ao intraexaminador, a confiabilidade intrateste foi excelente e não apresentou erro sistemático e aleatório.

BACKGROUND: The bridge test with unilateral knee extension evaluates the stability of the trunk and pelvis. The evaluation of this stability can contribute to the understanding of the occurrence of musculoskeletal injuries. OBJECTIVES: To investigate the intra- and inter-rater reliability of a qualitative analysis and intra-test reliability of a quantitative analysis of transverse plane pelvic alignment during the bridge test with unilateral knee extension. METHOD: Thirty participants (24.73±4.24 years old) were tested. The qualitative analysis was conducted by asking two raters to judge the transverse plane pelvic alignment and its reliability was assessed with the weighted kappa coefficient (k w). The quantitative analysis was conducted by measuring the greatest pelvic tilt angle in transverse plane and its reliability was assessed by use of the intraclass correlation coefficient (ICC); the mean change, which was evaluated using 95% confidence interval of the mean difference (95%CI ) and Bland-Altman plot; and the quantification of measurement variability, which was assessed using standard error of measurement (SEM) and the coefficient of variation of the typical error (CV TE). In addition, the minimal detectable change (MDC95) was determined. RESULTS: The intra-rater reliability ranged from fair to moderate (k w=0.32 to 0.58) and the inter-rater reliability was substantial (k w=0.80). The intra-test reliability was excellent (ICC=0.82), the 95% CI ranged from -0.51º to 1.99º, the SEM was 2.38º and the CV TE was 28.75%. The MDC95 was 6.59º. CONCLUSIONS: The inter-rater reliability was greater than the intra-rater reliability; the intra-test reliability was excellent and showed no systematic or random error.

Analysis of the profile, areas of action and abilities of Brazilian sports physical therapists working with soccer and volleyball.

OBJECTIVE: To analyze the profile of Brazilian physical therapists working with soccer and volleyball professional teams, by verifying their level of education (graduate or undergraduate), as well as their role and insertion within the interdisciplinary team. METHODS: Structured questionnaires were administered to forty-nine physical therapists working at soccer, volleyball clubs and Brazilian national teams. These questionnaires provided data on social demographic, characteristics of the work environment and organization of clinical practice and its domains. RESULTS: From the 49 participants in this study only five were female. Mean age of all participants was 32.2 years. The majority of the sports physical therapists had specialization degrees in different areas (78.2%), were hired through referral (78.2%), worked more than 8 hours a day or were exclusively dedicated to their clubs (80.0%) and earned seven to ten Brazilian minimal wages (58.2%). They reported to have participation in the domains of emergency care (87.3%), prevention (92.7%), functional rehabilitation (98.2%) and return to competition (100%). They had interdisciplinary relationships with physical educators during functional rehabilitation programs (70.9%) and with physicians in the decision process of return to activity after rehabilitation (74.5%) and on the veto of an athlete to take part in practices or matches (63.6%). Therapists also complained of threats to their professional autonomy, specially directed by the team's physician. CONCLUSION: There is still a need to invest in continuing education of sports physical therapists with the objective to improve their educational level and to strengthen their professional autonomy.

Análise do perfil, funções e habilidades do fisioterapeuta com atuação na área esportiva nas modalidades de futebol e voleibol no Brasil / Analysis of the profile, areas of action and abilities of Brazilian sports physical therapists working with soccer and volleyball

OBJETIVO: Investigar o perfil do fisioterapeuta com atuação na área esportiva nas modalidades de futebol e voleibol no Brasil no que tange à sua formação, atuação e grau de autonomia dentro da equipe interdisciplinar. MÉTODOS: Foram analisados questionários estruturados para levantamento de dados sociodemográficos, dados relativos ao ambiente de trabalho e à prática clínica e os seus domínios, referentes a 49 fisioterapeutas de clubes e seleções de futebol e voleibol. RESULTADOS: Do total de entrevistados, apenas cinco fisioterapeutas eram do sexo feminino, e a idade média do grupo era de 32,2 anos. A maioria dos fisioterapeutas brasileiros que atuam no esporte possuem especialização em diversas áreas (78,2 por cento), foram contratados por indicação (78,2 por cento), trabalham mais de 8 horas/dia ou em regime de dedicação exclusiva (80,0 por cento) e recebem de sete a dez ou mais salários mínimos (58,2 por cento). Além disso, observou-se uma grande participação do fisioterapeuta nos domínios do atendimento emergencial (87,3 por cento), prevenção (92,7 por cento), reabilitação funcional (98,2 por cento) e retorno após lesão (100 por cento). O fisioterapeuta com atuação no esporte relata haver uma boa relação interdisciplinar, sobretudo com o preparador físico na reabilitação funcional (70,9 por cento), com o médico do clube na decisão do retorno do atleta após reabilitação (74,5 por cento) e no veto ou liberação do atleta para jogos/treinos (63,6 por cento). Entretanto, muitos reclamaram de ameaças à sua autonomia, principalmente pelo profissional médico. CONCLUSÃO: Ainda existe a necessidade de investir na formação específica do profissional fisioterapeuta esportivo, visando a uma melhor especialização na área esportiva e consolidando conceitos importantes da área por meio de um melhor entendimento de referenciais teóricos e de atuação clínica.

OBJECTIVE: To analyze the profile of Brazilian physical therapists working with soccer and volleyball professional teams, by verifying their level of education (graduate or undergraduate), as well as their role and insertion within the interdisciplinary team. METHODS: Structured questionnaires were administered to forty-nine physical therapists working at soccer, volleyball clubs and Brazilian national teams. These questionnaires provided data on social demographic, characteristics of the work environment and organization of clinical practice and its domains. RESULTS: From the 49 participants in this study only five were female. Mean age of all participants was 32.2 years. The majority of the sports physical therapists had specialization degrees in different areas (78.2 percent), were hired through referral (78.2 percent), worked more than 8 hours a day or were exclusively dedicated to their clubs (80.0 percent) and earned seven to ten Brazilian minimal wages (58.2 percent). They reported to have participation in the domains of emergency care (87.3 percent), prevention (92.7 percent), functional rehabilitation (98.2 percent) and return to competition (100 percent). They had interdisciplinary relationships with physical educators during functional rehabilitation programs (70.9 percent) and with physicians in the decision process of return to activity after rehabilitation (74.5 percent) and on the veto of an athlete to take part in practices or matches (63.6 percent). Therapists also complained of threats to their professional autonomy, specially directed by the team's physician. CONCLUSION: There is still a need to invest in continuing education of sports physical therapists with the objective to improve their educational level and to strengthen their professional autonomy.