Short-term Recovery Following Resistance Exercise Leading or not to Failure: How does manipulating the 'level of effort' impact post-exercise recovery? What are potential implications for optimizing athletic performance?

This study analyzed the time course of recovery following 2 resistance exercise protocols differing in level of effort: maximum (to failure) vs. half-maximum number of repetitions per set. 9 males performed 3 sets of 4 vs. 8 repetitions with their 80% 1RM load, 3x4(8) vs. 3x8(8), in the bench press and squat. Several time-points from 24h pre- to 48h post-exercise were established to assess the mechanical (countermovement jump height, CMJ; velocity against the 1ms(-1) load, V-1-load), biochemical (testosterone, cortisol, GH, prolactin, IGF-1, CK) and heart rate variability (HRV) and complexity (HRC) response to exercise. 3x8(8) resulted in greater neuromuscular fatigue (higher reductions in repetition velocity and velocity against V-1-load) than 3x4(8). CMJ remained reduced up to 48h post-exercise following 3x8(8), whereas it was recovered after 6h for 3x4(8). Significantly greater prolactin and IGF-1 levels were found for 3x8(8) vs. 3x4(8). Significant reductions in HRV and HRC were observed for 3x8(8) vs. 3x4(8) in the immediate recovery. Performing a half-maximum number of repetitions per set resulted in: 1) a stimulus of faster mean repetition velocities; 2) lower impairment of neuromuscular performance and faster recovery; 3) reduced hormonal response and muscle damage; and 4) lower reduction in HRV and HRC following exercise.