Static stretching, e.g. toe touching, weakens muscles and does not prevent injury.
Researchers now believe that holding a stretch for 20 to 30 seconds — known as static stretching — actually weakens muscles.
Studies have found that stretching decreases muscle strength by as much as 30 percent.
The straining muscle becomes less responsive and stays weakened for up to 30 minutes after stretching.
Stretching one leg’s muscles can even reduce strength in the other leg as well, probably because the central nervous system rebels against the movements.
A well-designed warm-up starts by increasing body heat and blood flow with aerobic activity, such as light jogging for a maximum of 5 to 10 minutes.