Hamstring injuries are one of the most common injuries in sports that involve high speed running and kicking. In soccer and Australian football it is the most prevalent injury contributing to 12-15% of overall injuries annually.
Now for the confusing stuff, I’ll try to keep it simple. The hamstring group is comprised of 3 separate muscles; biceps femoris, semimembranosus and semitendinosus. The two “semis” are located on the inside of the back of your leg while biceps femoris is located on the outside. Biceps femoris is the most commonly injuries of the three.
The majority of hamstring injuries occur while sprinting when the muscle is highly active and under stress. This type of hamstring tear commonly occurs during the swing phase of sprinting. During the swing phase your leg is off the ground and knee is near full extension (knee is straightening) and the hamstring is controlling the movement, it does so through an eccentric contraction (contracting while lengthening).
The tear usually occurs on the change over from the hamstring lengthening under contraction (eccentrically) to the hamstring shortening under contraction (concentrically), at the end of the swing phase. It is only when the athlete plants the foot after the swing phase (entering the stance phase) that the tear is felt. The contraction during the stance phase tears the muscle further and causes more pain and discomfort.
Factors that contribute to hamstring injuries:
- Previous injuries: Previous hamstring, groin, calf and knee injuries have been associated with hamstring injuries.
- Flexibility: Studies show that stretching practices decrease the amount of hamstring injuries.
- Strength: Low hamstring strength has been shown to be a risk factor. Sports vary but a ratio of 3:2 in favour of quads is ideal for most sports.
- Weak core: Stability work for the core has been proven to help with hamstring injury prevention.
- Low back/Hip problems: Lumbar spine disorders can affect the hamstring due to nerve root impingement and hip tilts can put excess pressure on the hamstring.
R.I.C.E protocol should be used for the first 48hours after the injury occurs: (Rest, Ice, Compression, and Elevation).
Next time we will discuss how to prevent, treat and rehab a hamstring strain.