STRENGTH-TRAINING PRODUCES A CHANGE IN AEROBIC FUNCTION
Pogliaghi, S., Spigolon, G., & Fontana, F. Y. (2016). “Excess” VO2: the effect of strength training on metabolic efficiency and exercise tolerance. Medicine & Science in Sports & Exercise, 48(5), Supplement abstract number 736.
"During whole-body physical activity (e.g. cycling) exercise capacity is reduced by an “excess” in oxygen cost (VO2) relative to power output (PO) (i.e. higher VO2/PO ratio) that appears above the lactate threshold. This loss of muscle efficiency, of which type I fibers fatigue and/or increased type II fibers recruitment are putative causes, 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 “excess” VO2 during an incremental cycling-exercise. Young healthy males (N = 16) were randomly assigned to a control and a strength-training group (three, one-hour sessions per week). Pre- and post- five weeks of intervention, the VO2 and power output relationship during an incremental test to exhaustion was modeled using a double-linear fit: the slopes of the VO2/PO relationship below (S1) and above (S2) the lactate threshold were calculated. Peak power deficit was calculated as: (maximal aerobic power as estimated based on VO2max and the VO2:PO ratio below lactate threshold) minus (experimentally attained maximum power output).
For the strength-training group: maximum force in a squat significantly increased while VO2max and maximum power output did not change. A significant “excess” VO2 was present before strength-training (S1 was greater than S2) and disappeared post-training (S2 was not different to S1) along with a significant reduction in power output increases. No changes were detected for the control group.
Implication. Implication. In agreement with the hypothesis, strength-training significantly reduced the “excess” VO2 during an incremental cycling-exercise. This finding supports a role of strength-training for improving aerobic exercise capacity "through an attenuation of muscle inefficiency in the heavy-exercise domain".
It is hard to reconcile the mechanism or functioning that appeared to "work" in this study. That general strength-training programs improve the aerobic functioning of a specific exercise is rarely demonstrated in the scientific literature. In the case of neophyte or untrained subjects, any physical activity usually produces an initial change in most physiological and performance factors up to the stage where the Specificity of Training Principle becomes the governing factor for training effects.
As the authors suggest, further research needs to be conducted on subjects of different trained-states and different activities.
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