Isokinetic dynamometry assessment of the transition period between eccentric and concentric hamstring contractions in athletes with a history of hamstring injury.

The study was observational and retrospective, so it compared existing groups rather than assigning treatment, and it cannot show that injury caused the measured differences. The groups were not comparable in sport intensity: 10 of 26 injured athletes practiced high-intensity sport, while none of 31 controls did. Healthy controls were staff at the rehabilitation center and were slightly older than injured athletes, so background differences may have affected the comparisons. The injured athletes were tested a mean 9.2 months after injury, which is longer than the average recovery time of about 6 weeks, so some may have fully recovered. The transition period was calculated from recordings spaced at 3.9 ms, and the authors said measurement precision may have limited certainty. The sample was small, with 57 participants, which limits statistical power.

The authors declared no financial support for this work or its publication.

Do not conclude that the transition period is a useful clinical marker. It did not differ between injured athletes and controls, and the authors said measurement precision may have limited certainty.