Tennis

Shoulder Torque Production and Muscular Balance after Long and Short Tennis Points

Tennis is an asymmetric sport characterized by a systematic repetition of specific movements that may cause disturbances in muscular strength, power, and torque. Thus, we assessed (i) the torque, power, ratio production, and bilateral asymmetries in the shoulder's external and internal rotations at 90 and 180°/s angular velocities, and (ii) the point duration influence of the above-mentioned variables. Twenty competitive tennis players performed external and internal shoulder rotations; an isokinetic evaluation was conducted of the dominant and non-dominant upper limbs before and after five and ten forehands. A higher torque production in the shoulder's internal rotations at 90 and 180°/s was observed for the dominant vs. non-dominant sides (e.g., 63.1 ± 15.6 vs. 45.9 ± 9.8% and 62.5 ± 17.3 vs. 44.0 ± 12.6% of peak torque/body mass, p < 0.05). The peak torque decreased only after ten forehands (38.3 ± 15.8 vs. 38.2 ± 15.8 and 39.3 ± 16.1 vs. 38.1 ± 15.6 Nm, respectively, p < 0.05), but without impacting speed or accuracy. Unilateral systematic actions of tennis players caused contralateral asymmetries, evidencing the importance of implementing compensatory training. The forehand kinematic assessment suggests that racket and wrist amplitude, as well as speed, are important success determinants in tennis.

Diagnostic Validity of an Isokinetic Testing to Identify Partial Anterior Cruciate Ligament Injuries

OBJECTIVE

To assess the diagnostic validity of an isokinetic testing to detect partial injuries on the anterior cruciate ligament (ACL).

DESIGN

Prospective diagnostic study.

SETTINGS

Orthopedic clinic, physiotherapy clinic, orthopedic hospital, and diagnostic/image clinic.

PARTICIPANTS

Consecutive patients (n = 29) with unilateral knee complaint submitted to physical examination, magnetic resonance images (MRIs), and isokinetic testing prior to surgery of ACL reconstruction.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

The isokinetic torque curves data from extensor and flexor muscles were converted to frequency domain by fast Fourier transformation and compared with healthy contralateral limb. Differences were categorized as unstable knees and these conclusions were compared with patient's physical examinations (doctor's conclusion on ACL integrity) and MRIs (as the radiologist conclusions on ACL integrity). After surgery, all intraoperatively confirmed partial injured patient's data were collected. The diagnostic accuracy measures to compare the conclusions of all 3 professionals included sensitivity, specificity, positive predictive value, negative predictive value, disease prevalence, positive likelihood ratio, and accuracy-all using a confidence interval of 95%.

RESULTS

Compared with MRI, the sensitivity of isokinetic test for an ACL partial injury was 90.00%, specificity 83.33%, positive predictive value 52.94%, negative predictive value 97.56%, and accuracy 84.48%. Compared with physical examination, the sensitivity of isokinetic test for an ACL partial injury was 85.71%, specificity 78.43%, positive predictive value 35.29%, negative predictive value 97.56%, and accuracy 79.31%.

CONCLUSIONS

This method of isokinetic data analysis through fast Fourier transformation can be used to improve diagnostic accuracy of a difficult detection injury. Even present, a partial ACL injury can produce a stable knee during isokinetic testing and could be used to detect candidates for conservative treatment based on strengthening exercises, reducing surgery risks, and financial and social impact on patient's life.

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.