Hamstring injuries are very common among athletes and sports participants. They can be very mild or very disabling. Sprinters are especially susceptible. At full speed, the hamstring muscle contracts very fast to generate power needed for the run.
During sprinting, the hamstrings swing the thigh forward while bending the knee at the same time. When everything is in balance, the body’s center of gravity moves forward very smoothly and very quickly.
Any muscle deficit or imbalance of the hamstrings as they function in both capacities (as hip extensors and knee flexors) can lead to an injury. Olympic contenders have finely tuned bodies. They train every day and benefit from the expert advice of their trainers and coaches. The benefit of these counselors keeps the athlete in top shape and in the game (or in this case, on the track).
If there was a preseason loss of muscle strength in either concentric hip extension or eccentric knee flexion, the risk of a hamstring injury goes up. Concentric refers to muscle contractions as the muscle is shortening. An eccentric contraction is the action of a shortened muscle lengthening.
The length of time it takes to recover from a muscle injury depends on many factors. The degree of injury (mild sprain to complete rupture), strength, and flexibility all contribute to recovery. Other factors such as nutrition, fatigue, and intensity of preinjury training schedule can make a difference.