Acute effects of static stretching duration on isokinetic peak torque production of soccer players

Summary 

Recent research demonstrates that stretching prior to physical activity decreases performance. However, these stretching bouts are not representative of athletes during warm up procedures, as they are usually time consuming. The aim of the present study was to examine whether the duration of acute static stretching is responsible for losses in isokinetic peak torque production.

Fourteen young, male, talented, semiprofessional soccer players, from different Greek first national division teams, with an average age of 18.5±0.6 years, height of 177.6±4.3cm, body mass of 70.8±3.5kg and 8.4±0.5 years of training, were randomly selected to take part in the study. All participants performed three static stretching protocols, in nonconsecutive training session. The first stretching protocol was performed once for 30s (volume 30), the second 10 times for 30s (volume 300) and the third 16 times for 30s (volume 480).

Range of motion (ROM) was determined during knee flexion, using a goniometer. The peak torque of the dominant leg extensors was measured on a Cybex NORM dynamometer at angular velocities of 60, 90, 150, 210 and 270°·s⁻¹. The results of the statistical analysis indicated that peak torque remained unchanged following the static stretching for 30s in all angular velocities, while it decreased (P<0.01 to P<0.001) following the static stretching for 5 or 8min in all angular velocities. The findings suggest that a single stretch (training volume 30s) does not produce decreases in peak torque compared to multiple stretches (training volume 480s).

Keywords: Flexibility, Stretching duration, Range of motion, Isokinetic peak torque, Strength loss