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Dynamic Movements and Timed Static Contractions

The relationship in exercise between dynamic movements and Timed Static Contractions (TSC) is something that is often discussed and debated. Is performing a dynamic movement a more effective way to inroad the musculature? Is TSC a safer and more efficient way to achieve maximum benefit? As Total Results instructors, we have many "tools in our toolbox" to help clients achieve their exercise goals, and we use both TSC and dynamic movements as needed. A closer look at both methods will give us a better understanding of when and why to use each one.

In our exercise protocol, a dynamic movement involves raising and lowering the resistance in approximately ten seconds (in each direction) through a safe, pain-free range of motion. This will continue until forward movement of the resistance in proper form is no longer possible, at which point the subject will continue to push for an additional five to ten seconds (thorough inroad). This is done to stimulate the body's growth mechanism, and given adequate sleep, hydration, nutrition, and sufficient time, will result in increases in strength, metabolic and cardiovascular conditioning, maintenance of insulin sensitivity, enhanced flexibility, and greater resistance to injury. There are only two objective measurements of muscular effort: zero and 100 percent. While we still do not know and cannot measure what the exact percentage of effort is required to stimulate the growth mechanism, we do know that putting forth zero effort accomplishes nothing of value. That means that in order to be certain that we have created an adequate body stimulus, we should put forth 100 percent effort. It is fairly easy to know that 100 percent effort has been put forth on a dynamic movement because forward movement of the movement arm is no longer possible in proper form. This means that your muscles' force output has dropped below the weight selected on the weight stack. It is also much more objective to track progress with a dynamic movement because you have a weight value and time under load (TUL)/number of repetitions to record on the subject's chart. While those are certainly not the only means of measuring progress, they are two of the more important markers in terms of determining exercise frequency and volume.

Timed Static Contraction involves contracting the targeted musculature without producing any movement. It is an outgrowth of the old isometric (the joint angle and muscle length do not change) exercise concept, but applied in a much safer manner. It can be done with our exercise machines or with other equipment (for the Abduction and Adduction exercises we use a yoga strap and a foam roller, respectively). A TSC exercise will last 90 seconds and will involve three stages of effort. In the first stage, the subject will take a few seconds to slowly ramp up to a 50 percent effort (a contraction that would probably be unpleasant to sustain for more than a few minutes); the second stage will involve slowly working up to approximately a 75 percent effort (almost as hard as you dare); the final stage will have the client slowly work up to a 100 percent effort (as hard as you dare). To guard against potential injury, the instructor should always phrase the instruction in precisely that way, rather than "as hard as you can." The subject should exercise good judgement in interpreting and following through on these instructions. The major drawback to TSC, at least as we utilize it here at Total Results, is that there is no way to objectively measure force output, which means that tracking progress is mostly subjective. Ken Hutchins, who invented our exercise protocol, has developed exercise machines that have both digital and analog computer feedback which can quantify a number value for force output and objectively measure progress. Ken works with many clients that are severely debilitated, and has been able to achieve some pretty amazing results with these machines. While I have never used these machines before, I have read extensively about them and would love to experience them for myself.

Which is the better way to go? Both dynamic movements and Timed Static Contractions are valuable tools to use with a variety of exercise subjects. That being said, I prefer to use a dynamic movement whenever possible. Regardless of which method we use, the primary objective of exercise is to inroad the musculature as safely and thoroughly as possible in minimum time. Your muscles' main function is to produce force; they don't really know or care if they are making a movement arm move. While TSC can be beneficial in working around many joint issues (such as shoulder problems), we can do similar things while using dynamic movements, like gapping the weight stack to alter starting or ending positions and limiting range of motion. This is where you can use trial and error and do a cost/benefit analysis. Sometimes avoiding or minimizing joint pain by using TSC outweighs not being able to objectively measure progress on a given exercise. When going from TSC back to a dynamic movement after an extended period of time, one should expect to use a lower weight on that exercise due to a loss of skill. I have recently transitioned a few long term clients from TSC back to a dynamic movement on the Seated Leg Curl exercise; they had originally switched to TSC due to knee pain. I admit that this is a very small sample size, but I'm happy to report that all three clients have performed extremely well and have experienced no knee pain.

Working to build strength is the most effective way to minimize joint pain and increase functionality. Maintaining the ability to move is a key factor in one's quality of life as we age. Both dynamic movements and Timed Static Contractions are important tools in the Total Results instructor toolbox to help you achieve your goals and get the most out of life. Get started today!

Posted September 10, 2019 by Tim Rankin