Do the acute biochemical and neuromuscular responses justify the classification of strength- and hypertrophy-type resistance exercise?

This study aimed to examine a wide profile of acute biochemical and neuromuscular responses to strength (STR) and hypertrophy (HYP) resistance exercise (RE). Seven trained men completed an STR workout (4 × 6 repetitions, 85% 1 repetition maximum [1RM], 5-minute rest periods), an HYP workout (4 × 10 repetitions, 70% 1RM, 90-second rest periods), and a control condition (CON) in a randomized crossover design. Peak force (PF), rate of force development (RFD), and muscle activity were quantified before and after exercise during an isometric squat protocol. Blood samples were taken 20, 10, and 0 minutes before and 0, 10, and 60 minutes after exercise to measure the concentration of blood lactate (BL), pH, and a number of electrolytes that were corrected for plasma volume changes. No differences were observed between the workouts for changes in PF, RFD, or muscle activity. Repeated contrasts revealed a greater (p ≤ 0.05) increase in BL concentration and reduction in pH after the HYP protocol than the STR or CON conditions. There were similar but significant (p ≤ 0.05) changes in the concentration of a number of electrolytes after both workouts, and a handful of these changes displayed significant correlations with the PF reductions observed after the HYP condition. Although the STR and HYP workouts were significantly different in terms of intensity, volume, and rest, these differences were only observable in the acid-base responses. The present findings reinforce the need for practitioners to look beyond the classification of RE workouts when aiming to elicit specific physiological responses.

RCT Entities:   Population Interventions Outcomes