Our results suggest that 6 repeated active knee extensions before stretching are sufficient to increase knee joint angle and that a protocol of 4 30-second static stretches can further increase this angle. However, these range-of-motion gains are only temporary and short in duration. Athletes who statically stretch and then wait longer than 3 minutes before entering a game or practice can expect to lose the range of motion gained. Future research should determine whether intermittent stretching or activity alone is sufficient to maintain temporary increases in range of motion obtained from acute stretching
bouts. Research determining the most efficient type of acute stretching to effect same-day range-of-motion increases is warranted, as is investigation to determine the optimal duration of stretch to produce long-term or permanent changes. Finally, comparisons between men and women, across age groups, and between subjects with range restriction '200 and