The power of contraction/release techniques


What exercise technique builds strength and flexibility, can be performed anywhere, even in bed, requires no equipment, and can even be performed when you’re injured?

Of course, I gave it away with the title. Still don’t know what that is?

These are contraction/release techniques, of which there are several types.

First, we have isometric contractions. These were popular back when Jack Lalanne promoted them on TV in the ’60s. In this type of contraction/release, the joint angle does not change; only the muscles contract and release. (1) For example, sit in the yoga posture bound angle (baddha konasana). Let the knees fall toward the ground. Contract all the muscle of the buttocks and groin, without pushing the knees closer to the ground. 

Exercise physiologists have long known that the optimal time of contraction is 5 to 10 seconds; usually 6. Optimal intensity is 100 percent. Not easy! Then rest a sec or two. Repeat five more times, and your muscles begin to fail.

On the downside, strengthening occurs only in that specific joint angle, so you have to work it at a few different angles to be effective in a range of motion (ROM). On the upside, these are great for the unfortunately hyperflexible, to build joint stability. Also, if a joint is injured it may be painful to move against resistance. (2)

In isotonic contractions, the joint angle(s) changes. (1) There are two kinds: eccentric and concentric contractions. Going back to the bound angle posture example, in the eccentric contraction, you use your hands to push your knees down, as you simultaneously push your knees toward each other.  In the concentric contraction, you would push the knees down toward the ground.

Sometimes a weak joint prevents increased ROM. The body is protecting itself from dangerous over-stretching. Try to first strengthen the joint using an isometric or isotonic contraction/release at the full end of the ROM for a few weeks. You’ll soon see improvement in ROM.

Talking about increasing ROM is stretching, right? Isotonic contraction/release techniques, when used specifically to increase flexibility, just have different names. Have you ever heard of Proprioreceptive Neuromuscular Facilitation (PNF)? See the eccentric example above. If we focus on flexibility, it’s call PNF; on strength, it’s called isotonic eccentric contraction. These are often done with a partner supplying the resistance. (4)

Eccentric contraction for strengthening or PNF for flexibility.

Eccentric contraction for strengthening or PNF for flexibility.

Reciprocal Inhibition, another “stretching” technique that is basically a concentric contraction, calls for contracting the muscle opposing the one(s) you want to stretch. In the bound angle posture example above, contracting the buttocks (agonist) signals the brain to relax the muscles in the groin (antagonist). (5)

Concentric contraction for strengthening or reciprocal inhibition for flexibility.

Concentric contraction for strengthening or reciprocal inhibition for flexibility.

All of these contraction/release techniques can get boring, unfortunately. Thankfully, we have yoga.

In Ashtanga Yoga, using the bandha is an important contraction/release technique. Bandhas are the energetic locks of the pelvic floor and the transverse abdominus that help build the incredible strength and flexibility of Ashtanga yogis. These bandhas, moola and uddhiyana respectively, are contracted on every exhale, and released on the inhale, depending on the power needs of the body. They are activated during transitions and while in the “state of the asana,” that is, while holding the posture. Although the bandha contraction/release may not be held for the entire 6 seconds, it is repeated in every possible joint angle of the hips and legs of each of the 72 postures of the Primary Series.

Strength and flexibility can be considered the yang and yin of functional movement; that is, complementary. Contraction/release techniques may help you overcome common strength and flexibility obstacles to performing more advanced yoga asana. I use them often in my Level II private training. Let’s investigate your obstacles to more flowing yoga and let me design some for you. Contact me now for a free consultation.


1) Exercise Physiology, Theory and Application to Fitness and Performance, 7th edition, Powers & Howley, McGraw Hill Higher Education, 2009, p. 160.

2) ACSM’s Resources for the Personal Trainer, 3rd edition; Lippincott Williams & Wilkins, Publisher Wolters Kluwer Health, Philadelphia. 2010, p 335.