by Sarah Apple Kingsley, pt, dpt
If you are familiar with LYT, you know by now that we LOVE eccentric exercise! If you are not, I will share with you why eccentric exercise is so important in tissue repair and recovery.
What does eccentric mean? Muscles contract in 3 different ways. The least stressful and straining is an isometric contraction in which the muscle activates without moving at all. Think of your bicep which controls elbow flexion. If you hold the arm at 90 degrees with a weight in your hand without letting the arm move, your bicep is having to contract isometrically to withstand the load. Concentric contraction is when the muscle works in its shortening phase. So for the bicep, its action is elbow flexion. When you actively bend your elbow holding that dumbbell now you are concentrically working the bicep. Eccentrics are when you work a muscle in its lengthening phase. In this case, begin by holding that weight with your elbow bent and trying to slowly control the lowering into full elbow extension (straightening). This motion is asking the bicep to work to control the elbow extension in its lengthening phase.
Eccentric contractions are much more challenging as you are asking the muscle to work against at a greater angle. For this reason, you get so much more bang for your buck performing only just a few reps/contractions of eccentric motions as opposed to doing those dumbbell curls all day long. Eccentric contractions help build muscle faster and more efficiently, and also require less oxygen which means eccentric muscle training puts less stress on the heart and is less likely to cause spikes in blood pressure. Moreover, eccentric contractions are shown to aid in breaking down adhesions throughout the muscle tissue in order to stimulate new cell regeneration and repair. This has shown to be especially effective when treating the rotator cuff.
The shoulder joint is one of the more common reasons why people seek PT treatment in clinics and there is frequently a loss of range of motion in shoulder internal and/or external rotation due to rotator cuff dysfunction. There could be scarring, a tear (minor or major), impingement, etc. The adhesions built up in the muscle due to impingement and repetitive microtrauma to the area cause restrictions, pain and deficits in ROM, active or passively, due to muscle guarding and therefore decreased muscle length. Continuously overstretching or attempting to passively mobilize the tissues and joint is frequently very painful and oftentimes unsuccessful.
By performing eccentric exercises, the body will work actively against the resistance in a lengthening manner, so that you feel somewhat in control of the motion creating decreased muscle guarding. With slow releases working on lengthening against resistance breaks down adhesions, while promoting more length in the muscle usually with each contraction. These exercises can be performed against manual resistance from a therapist or with use of a theraband. Eccentrics are especially great for improving internal and external shoulder rotation, but they can also be beneficial for shoulder flexion as well.
The main consideration however is the correct dosage. The key to these exercises’ effectiveness is that in order to promote tissue healing an adequate load must be applied. An over or underuse of load can further deteriorate the tendon structure. More studies need to be done on the proper application, which is why in my opinion these exercises in the form of tissue recovery for an injury are best performed manually by a therapist in order to properly grade the amount of resistance being applied and to track the level of fatigue in order to gauge repetitions. Additionally, I have found the ability to add a distraction moment to the glenohumeral joint at the same time makes the exercise more tolerable for the shoulder joint complex and is even more effective than self-exercise with a theraband.
As an example you can try, start with a light resistance band holding one side in each hand with your elbows bent at 90 degrees and in by your sides. Make sure the head of your arm bones are positioned well in the socket. If they tend to roll forwards, shrug your shoulders up, back and down before beginning. Pull the band apart with both hands coming into shoulder external rotation (the elbows stay in by your sides as the fists go out with your thumbs pointing up). Then as slowly as possible allow the fists to return back to starting position or even slightly further in towards your belly for shoulder internal rotation. Perform repetitions to fatigue but not pain.
We LOVE eccentrics of all forms in our LYT yoga practice so check out some classes on LYT daily for more eccentric exercise tips!