Fontana, F. Y., Spigolon, G., & Pogliaghi, S. (2016). VO2 slow-component: the effect of strength training on metabolic efficiency and exercise tolerance. Medicine & Science in Sports & Exercise, 48(5), Supplement abstract number 739.

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"The VO2 slow-component is a slowly developing increase in oxygen consumption (as a function of time, during a constant work-rate exercise (performed above the heavy-intensity boundary. This loss of muscle efficiency caused by Type I fiber-fatigue and/or increased Type II fibers recruitment, impairs exercise tolerance." This study tested the hypothesis that a strength-training intervention, by increasing maximal force and reducing the recruitment of high-threshold motor units at a given exercise intensity, will reduce the amplitude of VO2 slow-component and enhance exercise tolerance. Young males (N = 16) were randomly assigned to a control or a strength-training group (three, one-hour sessions per week). Pre- and post- a five-weeks intervention, Ss performed three repetitions of a 10-min constant work-rate exercise at delta50. VO2 was modeled using a bi-exponential equation and the magnitude of the VO2 slow-component was quantified. One of the constant work-rate trials (random order), was prolonged until task failure and time-to-exhaustion was measured.

Maximal force in the squat increased significantly and exercise tolerance also increased only in the strength-training group. VO2max and maximum power output were unaffected by either time or group.

Implication. Five weeks of strength-training significantly reduced the magnitude of the slow component (-80%) while increasing exercise tolerance in young healthy subjects.

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