Health&Nutrition

INJURIES: Hamstrung?

February 17, 2011
By Scott Howitt

“Doc, I keep stretching my hamstrings, but they’re always so tight and sore.”

I hear this complaint at my clinic all the time, from runners who can’t understand why they’ve developed hamstring problems despite their faithful stretching program. The truth is, most runners already have more than enough flexibility in their hamstrings - what they’re lacking is strength. Specifically, they need greater “eccentric” strength, the specific type of muscle contraction that helps decelerate the forward movement of the leg just before your foot hits the ground.

Hamstring strains are very common, and they heal slowly. That makes them particularly susceptible to re-injury if you try to resume running before rehabilitation is complete. To understand how to deal with them properly, you first need to understand what role they play in your stride.

The hamstrings make up the bulk of the muscle in the back of the thighs. They consist of the long and short head of the biceps femoris muscle, which runs to the outside of the knee, the semitendinosus and semimembranosus muscles that run to the inside of the knee.

The most obvious contribution the hamstrings make to running is providing propulsion by contracting to flex the knee and extend the hip, moving the body forward during the support phase of the running cycle. But they make another, less obvious contribution as your leg swings forward: they contract again to decelerate your leg. This is termed an “eccentric” contraction, because the muscle is contracting even as it’s being lengthened, opposite to the usual “concentric” contraction. Numerous studies have found that running injuries (and other sports injuries, for that matter) are most often associated with eccentric contractions.

Not only is weakness in your eccentric contractions a common cause of muscle injury, but it’s often confused with being inflexible as the muscle appears to be “too tight” to effectively lengthen.

Acute hamstring injuries are often linked to eccentric muscle contractions, but chronic injuries tend to be more complex. The hamstring muscles are connected through a kinetic chain to the pelvis, knee and foot, so weakness in any one of those units can affect the others. A continuous band of ligaments, muscles and fascia run all the way from your feet to your lower back. This means that running with a bum hamstring can trigger problems throughout your body.

Tip: If you can’t run without hamstring pain, stop! The biomechanical adaptation and likely muscle imbalance that you may be causing can actually cause a worse recurrent injury or perhaps a different, compensatory one.

So what should you do if you develop a hamstring problem? I suggest the following four steps.

(1) Get a diagnosis from a sports specialist. You need to figure out if it’s truly a hamstring strain, or if the hamstring is acting up in response to problems in your glutes, calves or other muscles.

(2) Seek appropriate conservative care such as Active Release therapy, instrument-assisted soft-tissue mobilization, acupuncture, kinesio-taping, and other therapeutic treatments.

(3) Most importantly, do your rehab exercises! This should involve develop the eccentric strength of your hamstrings, as well neuromuscular control exercises from the whole lumbar-pelvic region, such as planks and bridges.

(4) Before resuming training, have a running analysis performed by a health care professional or coach with expertise in sport biomechanics to uncover faulty running biomechanics and ensure proper technique.

Of course, you don’t have to wait until you’re already hamstrung to incorporate these techniques. Several researchers have found the eccentric hamstring exercises play a key role in avoiding injuries. Generally speaking, I advocate strength and flexibility work on off days to develop muscle balance and avoid muscle inhibition. Before running, start with a dynamic warmup including running drills (high knees, skips, butt kicks). Finish with a cool down that may incorporate partner-assisted stretching.

Eccentric hamstring exercises:

1. Eccentric box drops

2. Eccentric backwards steps

3. Eccentric loaded lunge drops

4. Stiff-legged eccentric deadlifts

5. Eccentric single-leg deadlifts

Dr. Scott Howitt is a chiropractor, kinesiologist, sports science and rehab specialist at Sports Performance Centres in Thornhill, Mississauga and Vaughan, Ont.