Changes in knee flexion-extension performance and hamstring-to-quadriceps ratio during a fatiguing isokinetic protocol in male professional futsal players

ABSTRACT

Knee flexion (KF) and extension (KE) performance and hamstring-to-quadriceps (H:Q) ratio are used to estimate injury risk and readiness to return to sport. However, the traditional measures (i.e. non-fatigued state and by peak torque [PT]) may not reflect the thigh and knee injury conditions (i.e. high-speed actions and fatigue presence). We verified the effects of a high-speed isokinetic fatigue protocol (30 consecutive KF and KE concentric contractions at 300°/s) on KF and KE performance and H:Q ratios assessed through different parameters (i.e. PT, work, average and peak power) in male professional futsal players (n = 17). A significant (p < 0.01) time × muscle group interaction was verified. There were reductions (p < 0.01) in KF by PT (84.79 ± 15.05 to 50.29 ± 15.29 Nm), work (87.28 ± 14.46 to 39.00 ± 13.83 Nm), average power (227.81 ± 39.31 to 104.75 ± 31.24 W) and peak power (383.40 ± 59.90 to 191.39 ± 48.35 W). Similarly, KE performance decreased (p < 0.01) for all parameters (PT: 131.36 ± 16.05 to 81.61 ± 9.15 Nm; work: 148.83 ± 20.88 to 90.72 ± 11.89 Nm; average power: 148.83 ± 20.88 to 90.72 ± 11.89 W; peak power: 664.74 ± 85.32 to 398.38 ± 42.42 W). KF (−55.18 ± 13.91% to −40.94 ± 12.66%) showed a higher percentage decrease than KE (−40.46 ± 7.38% to −37.45 ± 6.61%). Finally, reductions (p < 0.01) in H:Q ratio by work, average and peak power but not by PT (p = 0.25) were verified. The tested methods can provide additional information about the athlete’s condition.

KEYWORDS:

• Injury & Prevention
• Strength
• Team sport
• Training
• Resistance

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

All authors certify that they have no affiliations with or involvement in any organisation or entity with any financial interest or non-financial interest in the subject matter or materials discussed in this manuscript.