Joy Sassoon, Age 60, Photographed by Tanya Constantine
In past posts, I have tried to give you some guidelines on how to use yoga poses to increase or maintain the strength of your both your bones and muscles (see Yoga for Strength: An Overview). Today based on some new information I have learned, I’d like to revisit my guidelines for how long to hold your poses because I’m going to make some different recommendations.Building Stronger Bones
For building stronger bones, I initially used information from Loren Fishman’s book Yoga for Osteoporosis, in which he cited an animal study that showed placing strain on a bone starts to stimulate new bone to be laid down as early as 8 seconds. But in his recently completed 10-year study that utilized 12 poses done over 12 minutes, Dr. Fishman had the participants hold the poses for 30 seconds each (nine of the poses were asymmetric and therefore would take 1 minute total to complete) with positive results. So for strengthening bones, I'm now going to suggest that you hold your postures for 30 seconds, if possible. Could you hold them for less than 30 seconds, especially if you are weak or fatigued? Sure, but we don’t have evidence at this time that those timings would be as effective for bone building. Building Stronger Muscles
In my post Yoga for Strength: An Overview, I recommended that holding your poses statically for 90 seconds would build muscle effectively. Unfortunately, I cannot locate the or research I used to make that statement. But in going back to look at this more closely for our upcoming book, I discovered some important facts I’d like to share with you today that flip my earlier recommendations almost upside down. There are two commonly used techniques to build muscle mass and strength, both in sports training and rehabilitation from injury. The first technique uses motion against resistance, called resistance training, as in curling a 10lb. weight up and down with your arm smoothly at the gym to build up your bicep. This utilizes what is known as “isotonic” muscle contraction (with the muscle contracting and visibly shortening during the curl) against some sort of resistance (the hand weight) to build muscle. And because you lower the weight down slowly, your bicep muscle also is contracting as it is grossly lengthening, which is called “eccentric” contraction. For this action to be effective, you have to do multiple repetitions. In our yoga practice, dynamic sequences or mini vinyasas could count as resistance training, especially if you do them more slowly. Since we are using our own body weight as the resistance, it may not work as quickly to build muscle as weight training, but it will still build strength. See below for more recommendations about how to use this technique in your asana practice. The second technique is isometric holds, usually accomplished by pushing or pulling on an immovable object, which maximally contracts the muscles involved without changing the gross length of the muscle (in other words, triggering an isometric contraction of those muscles). You can trigger the same response—although maybe not as maximally—by pretending to push or pull against an imaginary surface/object in yoga poses. For example, as you come into the full Warrior 2 pose (Virabradrasana 2) and hold it for a while, the leg muscles that keep you in position, such as the quadriceps, and the muscles that keep the arms out to your sides, such as the middle deltoids, are all working isometrically. You can enhance the number of muscles contracting isometrically by consciously firming all the muscles around a particular bone or joint towards the bone, sometimes called “hugging the bone”. In the world of sports training, these holds are usually for 8-10 seconds and done in a set of 6-12 reps, sometimes for more one set. If we applied this to our yoga practice, you could do six rounds of a mini vinyasa, staying in the full pose for 3-4 breaths (around 10 seconds), while hugging the muscles to your bones in all the major areas that you want to strengthen. You could even do a second set.
If you want to practice mini vinyasas for strength, which of these two techniques should you choose? Both ways can build strength, although the second technique might arguably do it faster. But if you are new to the practice, out of shape and weak, or simply wish to gently warm up your muscles, you might wish to start with the first technique. I, myself, prefer the first technique when I plan on practicing a static hold of the pose afterward. Now, what about longer isometric holds? Certain modern yoga systems encourage longer holds for poses that are strengthening, such as Warrior 3 (Virabradrasana 3. The Iyengar yoga system is a prime example of this approach. Isometric training is said to have the advantage of not putting as much stress on joints as other muscle building methods, which could be particularly useful in rehabbing an injury. Another strength building concept could apply here: the idea of taking the muscles to a point of fatigue, possibly indicated by muscle shakiness, as a way of stimulating the muscle to grow. But whether that is definitely applicable here is unclear. One study I reviewed did compare shorter 3 second isometric holds to longer 30 second holds, and found that the longer holds led to greater strength in the muscles tested. But another study showed no difference in strength gains in a group over 55 between short and longer holds, yet both groups did get stronger. And, for even longer holds, it may be that you will be increasing muscle endurance, rather than muscles strength, which is a different quality and characteristic of muscles.
The only warning about longer isometric holds is that they can cause an increase in blood pressure during the hold, so those with untreated hypertension should probably avoid this method until their blood pressure is under control.
Here are my new recommendations for building bone and muscle strength:
- For building bone strength, hold poses for 30 seconds or more, if possible.
- For building muscles using isotonic and eccentric contraction with a mini vinyasa, do the vinyasa slowly for six repetitions, possibly for two sets of six. As you increase in strength, you can add more reps per set.
- For building muscles isometrically with a mini vinyasa, hold the full pose for 8-10 seconds (3-4 breaths) for six repetitions, possibly for two sets of six. For example, if you were doing the Warrior 2 mini vinyasa, you would inhale from the starting position into the full pose, hold full Warrior 2 for four breaths, and then exhale back into the starting position.
- For building muscle strength and endurance in static poses, hold a full pose isometrically until your targeted muscles become shaky and feel fatigued, and then exit the pose. The length of time you hold the pose could short if you are weak, out of shape, or recovering from injury, or much longer if you are healthy and relatively strong to start. You can gradually build up your length of time in the pose as your strength increases.
Ram’s post Yoga Asanas: Resistance Training or Endurance Training? from few years back addresses some of these concepts in slightly different ways, and is worth a read if you have not seen it before. And thanks to our contributing writer Shelly Prosko for some additional information that helped clarify things for me! See these links:
The role of metabolites in strength training. II. Short versus long isometric contractions
Effects of isometric strength training on quadriceps muscle properties in over 55 year olds
Isometric Exercises & Static Strength Training
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