by Sarah Apple Kingsley, pt, dpt
If you are familiar with LYT and our yoga classes, you know by now that we LOVE eccentric exercise! If you are not, I will share with you why eccentric exercise is so beneficial 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 has 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 describe 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 causes 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 at a greater angle. For this reason, you get more effective exercises with 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. This 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 with online yoga classes.
The shoulder joint is one of the more common reasons why people seek PT treatment in clinics. There is frequently a loss of range of motion in the 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 passive, due to muscle guarding and therefore decreased muscle length. Continuously overstretching or attempting to passively mobilize the tissues and joints are 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. This is promoting more length in the muscle with each contraction. These exercises can be performed against manual resistance from a therapist or with the use of a theraband. Eccentrics are especially great for improving internal and external shoulder rotation and can be beneficial for shoulder flexion as well.
The main consideration is the correct exercise frequency. An adequate load must be applied to make sure these exercises are effective. 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 these exercises are best performed manually by a therapist. This will help to properly grade the amount of resistance being applied and to track the level of fatigue in order to gauge repetitions. 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. This can make it even more effective than self-exercise with a theraband.
To try the exercise, 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 heads 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 to starting position or even slightly further towards your belly for shoulder internal rotation. Perform repetitions until you are fatigued, but not in pain.
We LOVE eccentrics of all forms in our LYT yoga practice so check out some classes on LYT daily yoga for more eccentric exercise tips!
References:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4133471/
