Wednesday, October 14, 2009

Caloric Expense of Strength Training

Most people are pretty familiar with the idea of estimating Caloric expenditure with low-intensity cardio exercise. Many treadmills show 'Calories Burned' on the electronic display. It is easily calculated if the exerciser enters her weight.

Strength training, however, is a little more complicated. Conventional wisdom says you burn more Calories with continuous cardio, than intermittent strength training. When the Caloric expenditure of strength training is researched (with the same methods used to study low-intensity cardio- indirect calorimetry) this is confirmed. However, many good trainers and strength coaches have seen remarkable levels of fat loss (with appropriate dietary changes) with strength training-based workouts. Researchers finally realized that they were missing a crucial part of the caloric expenditure equation.

Strength training and other high-intensity exercise (i.e. sprinting) utilize a large portion of energy from anaerobic sources, in addition to aerobic sources. Where as low-intensity cardio uses mainly aerobic sources. Anaerobic energy usage is not always directly measured with traditional methods (indirect calorimetry, measuring expired gases).

When other measures of anaerobic energy expenditure (blood lactate levels) are utilized, total expenditure is higher. These techniques are just now being applied in research, so you probably won't hear about it for five or ten years.
Additionally, the overall (aerobic and anaerobic) metabolosm is elevated for an extended time (24-36 hours).
When researchers finally apply the appropriate methods to accurately measure total (aerobic and anaerobic) energy expenditure, we will have evidence to overturn conventional wisdom for fat loss. Meanwhile, my clients benefit from the most efficient fat loss training methods. Oh yeah, dietary restrictions are still important, too.

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