Muscles are more likely to tear when they are both contracting and lengthening at the same time, which sounds like a paradox but it’s actually a major part of muscle tissue’s job description: “eccentric” contractions put the brakes on elongation, which is why they are also called “braking” contractions.
Soccer is one of the best ways to injure a muscle. And eccentric contractions may actually be one of the best ways to get it back to full function.
They might also be the key to successful rehab. Rehabilitation training should generally try to imitate the circumstances of the injury. That is, you do roughly the same kind of thing that hurt you — more carefully, of course — to prepare your tissues to face the same stresses again someday.
Back in 2013, Askling et al tested the effectiveness of eccentric contraction in hamstring strain rehab. Seventy-five elite footballers with hurt hamstrings were randomly assigned to either regular or eccentric rehab exercises. The emphasis on eccentric contraction was wildly successful, taking almost half the time to get players back to the game: 28 days of rehab instead of 51! This is a dramatic result, which I actually trust quite a bit — a rare thing in my job. It is not technically “proven,” but it’s in the ballpark, and I’m going ot be doing this for sure — as prevention!
So what exactly was this miraculous protocol? It focused on “loading the hamstrings during extensive lengthening, mainly during eccentric muscle actions.” All exercise were performed painlessly. The exercises were “the extender,” “the diver,” and “the glider.” Here’s the complete routine (quoting extensively from the paper, but with some simplifications. There are videos freely provided by the British Medical Journal in the full text of Askling et al. — the “supplementary videos” numbered 1-3. I have linked each exercise title here to its video).
The Extender — Hold and stabilise the thigh of the injured leg with the hip flexed approximately 90° and then perform slow knee extensions to a point just before pain is felt. Twice per day, three sets of 12 repetitions.
The Diver — A simulated diving motion: hip flexion (from an upright trunk position) of the injured, standing leg and simultaneous stretching of the arms forward and attempting maximal hip extension of the lifted leg while keeping the pelvis horizontal; angles at the knee should be maintained at 10–20° in the standing leg and at 90° in the lifted leg. This is a tricky one, so go slow at first! Once every other day, three sets of six repetitions.
The Glider — The exercise is started from a position with upright trunk, one hand holding on to a support and legs slightly split. All the body weight should be on the heel of the injured (here left) leg with approximately 10–20° flexion in the knee. The motion is started by gliding backward on the other leg (note low friction sock) and stopped before pain is reached. The movement back to the starting position should be performed by the help of both arms, not using the injured leg. Over time, glide further and faster. Once every third day, three sets with four repetitions.
Applying these principles to other muscles would be require some creativity and savvy, but is definitely feasible. Happy contracting-while-lengthening!