Neuromuscular, perceptual and Lactate Responses comparing isometric and dynamic resistance training equalizing...

Isometric training (IT) has gained popularity as an alternative to dynamic resistance training (DRT) for improving neuromuscular performance but fatigue responses comparing both methods needs to be rigorously tested. The main objective of this work is to compare overall fatigue after DRT and isometric training IT performing different squat (SQ) variants equalizing session impulse. Nine trained subjects performed 4 protocols executing DRT-SQ, maximum IT-SQ contractions, or IT-SQ with 50 %MVIC equalizing session impulse. Mechanical, lactate, cardiovascular and perceptual responses were analyzed during protocols and at post0-24 h using frequentist (p < 0.05) and Bayesian approaches. Similar mechanical fatigue, cardiovascular responses, discomfort and fatigue perceptions were observed with trivial to moderate effects. Moderate to large effects were found for protocol 2 showing higher perceived effort, protocol 1 showing higher perceived cardiorespiratory effort and muscle soreness. Lactate was greater in protocols 1 and 3. In summary, short maximum or long submaximal IT induce similar mechanical fatigue to low-fatiguing DRT in the SQ; with different metabolic and perceptual responses depending on protocol type.