A grade 1 strain will take about a week of recovery time. A grade 1 strain hurts minimally, there is no pain walking, and motion isn't hindered. But it is imperative that you not exercise your leg. Increased work and stress can be put on the leg after week one. If you jump into swinging or exercising immediately after the injury, there is a good chance of increased severity.

A grade 2 hamstring strain will take two to three weeks of recovery for proper healing to occur. Do not allow yourself to put too much stress on the leg during this time because it will just increase the length of recovery time. With a grade 2 strain, you will have pain when walking, constricted range of motion, and tingling and pulling sensations in your leg. Until these symptoms are almost diminished, avoid physical activity.

A grade 3 hamstring strain will take three to five weeks for proper recovery. A person with a grade 3 strain may have trouble walking without assistance, i.e., crutches. Also there will heavy swelling in the area of the strain. Do not  perform any activity during this recovery time. If you re-strain the muscle the recovery time wil have to start all over again.