Ever wonder if those stretching exercises are really doing anything? How long does the effect last? And do you need to warm up before stretching? These are the questions physical therapists asked in a recent study.
Therapists often include stretching exercises in rehab programs. The idea is to increase the flexibility of muscles and tendons. The hamstring muscle behind the thigh and knee is an important muscle to stretch. Studies show muscle tightness is a common cause of hamstring injuries in athletes.
In this study, 56 volunteers between the ages of 18 and 42 were divided into four groups. Group one did warm-ups (climbing stairs) and a hamstring (static) stretch. Group two did just the static stretch. Group three just did the warm up. Group four was the control group. The control group didn’t do any warm-ups or stretching, but they did lie on the floor for two minutes.
Hamstring length was measured before and after the interventions. Measurements were taken at 15 minutes, one hour, four hours, and 24 hours after the stretching. The control group was measured at each of these times, too. The hamstring length was measured in degrees by seeing how far the subject could straighten the knee when lying on the floor with the hip flexed at 90 degrees. This test is called the active knee extension test.
The authors found a big difference in hamstring length after stretching. The greatest gain in muscle length took place in the first 15 minutes after stretching. The length was still there 24 hours later. Warm-up exercises before stretching didn’t seem to make any difference. The lasting effects of stretching are important to prevent injury and improve muscle function. Stretching should be done within 15 minutes of an activity to have the best effect.