Troy Garver discusses how sub-cellular structures called mitochondria power the muscle and how endurance weight training can increase the number of mitochondria.
Periodization | Troy Garver | mitochondrial (endurance) training
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In this podcast (Quicktime ipod compatible, 22MB; Google streaming flash video), Troy Garver and I begin a discussion of endurance training with a focus on the role of the mitochondria in supplying energy to muscles. As shown in the second picture at left, Troy explains that the mitochondria are sub-cellular structures where chemical reactions that power muscle contractions take place. High rep endurance training increases the number of mitochondria in muscle cells in order to continue supplying energy over longer periods of time.
I start the podcast by telling Troy that I am doing the high rep muscle definition workouts described in the book Serious Strength Training. Several months ago, Nancy Arnold and I started with 30 reps per exercise and no supersets and have now progressed to 50 reps per exercise with four exercises grouped together in a superset. According to Serious Strength Training, the goal of such high repetitions is to get the muscle's mitochondria to exhaust their normal ATP/CP and glycogen energy stores so that they burn fat, preferably near the muscle.
Howevever, as Troy notes, the body adapts. In a normal person, mitochondria occupy about 25% of cell volume. During mitochondrial training, the number of mitochondria can dramatically increase (for instance by 50 to 60% in 12 weeks). Further, in high repetition, low weight mitochondrial training, only a portion of each muscle's fibres are recruited for each repetition. Given these two facts, it takes longer and longer to exhaust the non-fat energy systems as you continue to perform mitochondrial workouts.
As presented in Serious Strength Training, mitochondrial muscle definition training is oriented towards bodybuilders trying to drive body fat as low as possible so that they get that chiseled, striated look. The tendency of the body to adapt to training stimulus means that bodybuilders have to constantly increase reps and intensity during muscle definition training to stay on track toward achieving their goals.
One thing that has fascinated me in the periodization scheme that Nancy and I began a year ago is the extent to which the body is a changing, dynamic system. What worked at the the start of a training regimen quickly loses its impact, so you must adapt your methods to continue pushing adaptation.
Additional Links
- The image of the mitochondrion was supplied by the Public Library of Science.
- This article discusses the time frames over which different energy sources are tapped over the duration of an exercise. As the table clearly shows, if an exercise endures from four to 10 minutes, the primary energy supply for muscular activity switches to fatty acids. I estimate that my supersets are taking from six to 10 minutes.
