Crossover-effect of Unilateral Dynamic Versus Static Stretch of Hamstrings Muscle on Hamstrings Muscle Length - a Randomized Controlled Trial

The crossover-effect within resistance- and strength training is more or less confirmed with multiple studies showing similar results. The studies shows an increase in muscle strength within the contralateral extremity being exercised. Regarding muscle length or mobility (flexibility) the crossover-effect have not been studied.

For a person to gain an increase in muscle strength mobility training in the form of stretching and flexibility training of our skeletal muscle is a common exercise. However, the evidence are scare and there are only a few studies comparing the effect of prolonged static stretching (> 90 sec) and dynamic flexibility training as to which of these methods has the best length-enhancing effect over time.

The purpose of this study is to compare the crossover-effect of eight weeks of oneleg dynamic flexibility training versus oneleg prolonged static stretching versus a nonstretching controlgroup on mobility in the hamstring muscles in adults with reduced mobility of the hamstring muscle. The aim is also to compare the sustained effect of flexibility training between the two groups, eight weeks after completion of the intervention.