Variação do equilíbrio muscular durante uma temporada em jogadores de futebol categoria sub-20

Evaluation of muscular and functional inter-limb asymmetries during mid-season in young male soccer athletes

BACKGROUND

To identify inter-limb asymmetries through the knee's muscular and lower limb functional performance in young male soccer athletes.

METHODS

Twenty male soccer athletes aged 17 to 19 from an under-20 team performed isokinetic tests at 60°/s., 120°/s., 180°/s., and 240°/s. To assess the knee extensors and flexors muscles and functional tests (hop tests and Y-balance test).

RESULTS

There were no significant differences between the dominant limb (DL) and non-dominant limb (NDL) in the knee extensors and flexors peak torque and hamstrings (H)/quadriceps(Q) conventional ratio. Moreover, no angular velocities observed inter-limb asymmetries seen by values higher than 10% in the isokinetic parameters. However, the H/Q conventional ratio shows borderline values in low angular velocities (60°/s. and 120°/s.). No significant changes were observed in the functional test performance between the DL and NDL. Furthermore, we did not see inter-limb asymmetries in both hop and Y-balance tests. On the contrary, the anterior distance reached was lower than found in the literature, and the composite score of the Y-balance test demonstrated values below the normative (>94%).

CONCLUSION

The data demonstrated that soccer athletes have muscular and functional inter-limb symmetry. However, they tend to have knee muscle imbalance in low velocities and dynamic balance deficits that might increase the risk of musculoskeletal injury.

TORQUE, POWER AND FATIGUE RATIO IN KNEE FLEXORS AND EXTENSORS OF SOCCER PLAYERS

ABSTRACT Introduction: Soccer is the most popular and practiced sport in the world and is characterized by high intensity movements. This high demand induces several types of locomotor system injury, and one of the intrinsic factors responsible for triggering these injuries is muscle imbalances, which can occur between limbs or between muscles groups of the same limb. Objective: To evaluate the muscular performance between knee flexor/extensor groups of both limbs in professional soccer athletes.: Methods: Isokinetic assessments were performed in 18 professional soccer athletes, with mean age of 26.9 ± 3.6 years and mean body mass index (BMI) of 23.9 ± 1.7 kg/m2.. The test protocol consisted of five concentric contractions of knee flexion and extension at angular velocity of 60o/sec, 15 contractions at 180o/sec and 30 contractions at 300o/sec in both limbs. Test paired t-test was used to verify the torque, power, and fatigue ratio of flexors and extensors of the dominant and non-dominant knee. Results: There was no significant difference between the evaluated members related to dominance (p>0.05). Regarding the torque ratio between flexors and extensors, we observed values below what is considered normal for this population, besides a higher fatigue index in knee flexor group when compared with the extensor group. Conclusion: No better performance was observed in the dominant limb, suggesting that, although this limb is preferred, this does not necessarily characterizes the better performance. The data also revealed an imbalance in the torque production capacity between the knee flexor and extensor groups, with an unfavorable ratio for the hamstrings, as well as a higher fatigue index in this group, which would make these muscles more susceptible to injures. Level of Evidence II; Diagnostic studies - Investigating a diagnostic test.

Flexor-extensor relationship knee after reconstruction of the anterior cruciate ligament

Introduction The incidence of knee injuries is very high in young adults. Anterior cruciate ligament (ACL) rupture is the most frequent of them. The isokinetic dynamometry evaluation determines the functional patterns of strength and muscle balance.Objective To compare the isokinetic hamstring/quadriceps peak torque and work ratios of young adults after surgical reconstruction of the anterior cruciate ligament.Methods We selected 33 medical records filed by the Isokinetic laboratory of the Physiotherapy Clinic of the Catholic University of Paraná (PUCPR), which belonged to patients who had undergone isokinetic assessment at the request of a physiotherapist or physician in Curitiba, Paraná. The tabulated data were: Hamstring/Quadriceps peak torque and work ratios of all injured and non-injured limbs at an angular velocity of 60°/s. Data were processed by the statistical software LHstat. Inferential statistics was used in order to apply the comparison test between means (unpaired t-test) with a confidence interval of 95%.Results The average flexion-extension ratio of the non-involved limb was lower than the involved limb both for peak torque (peak torque ratio of the non-involved limb: 56.1%; peak torque ratio of the involved limb: 66.3%; difference: 10.2%) and work (work ratio of the non-involved limb: 60.1%; work ratio of involved limb: 66.1%; difference: 6%).Conclusion : The average flexion/extension ratio found was adequate for both limbs and variables, however, the subjects presented a greater number of muscle asymmetries in the involved limb than in the non-involved limb.

Utilização do teste de 1-RM na mensuração da razão entre flexores e extensores de joelho em adultos jovens

A razão de força entre agonista/antagonista fornece informação significativa sobre o equilíbrio muscular sendo importante na detecção de alterações musculoesqueléticas, na orientação de medidas preventivas e na implementação de programas de treinamento específicos. A dinamometria isocinética fornece valores fidedignos sobre o torque gerado e, subsequentemente, sobre a razão de força entre flexores e extensores. Porém, trata-se de um método pouco acessível. Uma possível alternativa para avaliação de força é o teste de uma repetição máxima (1-RM), que é o mais utilizado para avaliação da força dinâmica. Contudo, não existem na literatura trabalhos que tenham utilizado o teste de 1-RM para quantificação da razão entre flexores e extensores de joelho. O objetivo deste estudo foi utilizar o teste de 1-RM na mensuração da razão entre flexores e extensores de joelho em adultos jovens, a fim de encontrar dados normativos. A amostra foi composta por 80 adultos jovens (com média de idade de 22,7 ± 3,40 anos), sendo 40 homens e 40 mulheres, sem lesões osteomioarticulares, que foram submetidos à aplicação do IPAQ-curto, pesagem e predição de 1-RM, aquecimento, teste de 1-RM unilateralmente nos bancos flexor e extensor e posterior análise de dados. Foram encontrados valores de razão agonista/antagonista de 52,34% (±9,72) para homens e 43,19% (±5,82) para mulheres (havendo uma diferença significativa entre os grupos). Valores de referência quanto à razão dos flexores e extensores de joelho utilizando o teste de 1-RM em adultos jovens foram encontrados, podendo servir como referência para indivíduos assintomáticos nessa faixa etária.