Understanding your hamstrings, how they work and how to prevent injury
Written by Dr. Daniel Shaye
It’s a classic scene: a pack of powerful runners glides quickly and effortlessly along the beach; their strides long and fluid. The background music emphasizes the runners’ grace and power, building to a crescendo of emotion and joy as the waves crash. Suddenly one of the runners falls out of formation, grasping his hamstring with a cry of pain; and the director screams, “Cut!” The scene needs to be re-shot; and if you’re the injured runner, you’ll feel like you’ve been shot in the back of the thigh.
Since hamstring injuries can be devastating, I’ve devoted two columns to the subject. This first article discusses anatomy, neurology and basic prevention and treatment strategies. The next column, which will appear as an online feature next month, reviews additional prevention strategies, including my personal, hamstring-friendly warm-up routine.
What are Hamstrings and How Do They Work
The hamstrings are three muscles on the back of each thigh: the semitendonosis and semimembranosus on the medial—closer to the midline of the body—back-side of the thigh, and the two-headed biceps femoris muscle on the lateral (outside) back-side of the thigh. Branches from the sciatic nerve trunk, which derives from nerve roots in the low back, supply these muscles. Hamstrings have several functions. A concentric contraction is the typical muscle contraction: the muscle acts and shortens. Eccentric contractions are the opposite: lengthening contractions. Imagine holding a weight in your hand and contracting the biceps to bend the elbow. Then reverse the exercise, lowering the weight slowly. The arm’s biceps muscle is now engaged in a lengthening contraction controlling the lowering rate. That’s an eccentric contraction. I believe that many hamstring strains occur during eccentric contractions as they attempt to control (slow or manage) the rate of knee flexion/extension during running. When they are overwhelmed during this control (eccentric) phase, or during what we tend to think of as traditional (concentric) contractions, we experience a hamstring strain.
Types of Strains
Hamstring strains vary in severity. In my practice, I’ve seen hamstring strains that were very subtle, all the way up to posterior thighs that were black from varying levels of tears. I’ve also seen purported hamstring strains that were in fact misdiagnosed sciatic or low back/disc problems.
A true hamstring strain occurs as a result of an overload event. This event can involve a slip or mis-step (macrotrauma), endurance overload (microtrauma or fatigue overload) and neurological dysfunction (the muscle is competent, but it doesn’t fire in the right way at the right time).
I know an athlete (non-runner) who has an answer for every injury: “stretch it out.” This advice is, well, terrible. Stretching actually inhibits muscle, so if a hamstring isn’t firing properly or sufficiently, then stretching hamstrings will do the opposite of what you desire—especially if they’re already injured or have stretch weakness. Conversely, if the quads are tight, stretching those opposing muscles may be a more effective strategy. The bottom line for hamstrings: randomly stretching is not a great strategy. Know what to stretch, when to stretch and why to stretch. Keep in mind that a runner will never be as flexible as a gymnast—and doesn’t need to be.
Try This Now
Here’s a tip you can use right now: compress your hamstrings. Little hard science links compression gear with lower hamstring injury rates, but anecdotally, this sort of gear seems to help support hamstrings and related muscles. When it’s cold, keep your legs warm. Sweat pants are a good bare-bones minimum for keeping legs warm on cold days, but modern elastic or compression gear not only keeps legs warm, but compresses and supports tissues even on the hottest days without sending you the med tent with heat injury. My read is that if it feels right, do it; if not, don’t. I opt for gentle, compressing leggings when the temperature is at or below freezing, or thigh-length compression gear when it’s warm and my hamstrings give me warning signals.
I’ll see you next month; or perhaps on the roads and trails, before that. Until then, happy running!
- Massage (Professional): If you’ve got a significant hamstring strain, a professional can get to the heart of the matter and knead, press or strip the muscle until it relaxes. You may not be able to sprint after, but sometimes walking without limping is a big plus.
- Massage (DIY style): Foam rollers, “sticks,” and a variety of other devices are ways for you to massage your own legs without contortions. They can be very helpful—though I’ve found that sometimes swallowing my pride and getting help is wise.
- Specialized soft tissue techniques: Graston, active release and a variety of other methods are commonly used by specialty-trained chiropractors and physical therapists. Metal or other tools, or properly employed thumbs and elbows, can be used to break up adhesions and free muscles and nerves to glide smoothly.
- Needling techniques: Sometimes it’s hard to get deep enough into the muscle to get to the “trigger points.” A technique called dry needling uses monofilament needles to pierce trigger points, which stimulates a healing reaction.
- Chiropractic: If you thought chiropractic was just for backs, think again. America’s national-caliber training camps and training centers for running all have affiliated or staff chiropractors to keep athletes balanced. A balanced athlete distributes stress to the hamstrings more evenly, and the chiropractic theory is that properly functioning spinal and other joints yields better function, better performance and fewer injuries.
- Therapeutic exercises: Some hamstring problems are the result of weakness, or intrinsic tightness, or tightness of the opposing (antagonistic) muscles. Sometimes hamstring problems can also be caused, at least in part, by bad posture and poor form that can to some extent be retrained. Gait analysis may be able to reveal some of your faults, as well as some solutions.
- Surgery: Surgical intervention for hamstring strains is rarely indicated. Only when hamstrings are completely torn (Grade III strain), or torn completely from their bony attachments, does surgery come into play.
Read Hamstrung: Preventing Injury to learn more about hamstrings and how to take care of them (includes visual fitness guide)