The acute effects of dynamic and static stretching on the knee isokinetic muscle strength and balance control in athletes

Objective To study the acute effect of static and dynamic stretching on the knee muscle strength and postural capacity in athletes. Patients and methods Fifteen judokas performed 2 stretching protocols (static and dynamic) on the muscles of both lower limbs with an interval of 48 hours in a random order. An evaluation of the dominant knee muscle strength with an isokinetic dynamometer CybexNormII was performed before and after each stretching protocol in a concentric mode at a speed of 60 and 180°/s. Each athlete was evaluated on the Satel ® plateform in static conditions open and closed eyes in the two trials. This evaluation was performed after a standard warm-up protocol (5 minutes on a bicycle ergometer) and a minute after the stretching protocol. The parameters were monitored: mediolateral (Long X) anterior-posterior deviations (Long Y) of the plantar center of pressure and the total area. Results Five judokas, with mean age of 21.3 ± 2.3 years, mean height of 177.8 ± 8.8 cm, and mean weight of 74.6 ± 14.6 kg participated in this study. We objectified an increase in the mean peak torque (PC) after the dynamic stretching protocol compared to the initial assessment at the speed of 60°/s in both the flexor ( P P  = 0.005) muscles. Furthermore, we found a decrease in the PC after the static stretching protocol at the same speed with a statistically significant difference in both flexor ( P P Discussion/Conclusion On one hand, this study confirms the value of dynamic muscle stretching on the gain of the isokinetic strength of the knee muscles. On the other hand, a deterioration of the postural following capacity after both static and dynamic stretching was observed.