In order to assess the effect of recovery on power and blood lactate, 10 males performed 10 sets (S1 to S10) of 6 repetitions of bench press at 70 % of their maximal strength, with 1 (Prot1), 3 (Prot3) or 5 (Prot5) min rest between sets. From the measurements of force and displacement of the bar, mean power during each repetition (MPR) and set (MPS), were calculated. Blood lactate was evaluated before and immediately after each set. No significant variations in power or blood lactate occurred during prot3 and prot5. From S4 to S10, significantly lower MPS (27 % decrease) and higher blood lactate (7.6±2.0 mmol/l) were demonstrated in prot1 VS prot3 or prot5. In spite of this, MPR in prot1 were significantly lower for repetitions 4, 5 and 6 only: MPR of repetitions 1, 2 and 3 were similar in the 3 protocols. During prot1 only, power decrease was related to lactate accumulation for all subjects (0.64 ≤ r ≤ 0.99, p ≤ 0.05). These results indicate that although muscular power and blood lactate were both affected by the recovery interval, acidosis was not the direct cause of fatigue during the 1 min rest condition. The concomitant effects of lactate accumulation and insufficient time for a complete resynthesis may have resulted in a diminution of PCr stores, leading to power decrements.
Key words
Resistance exercise - rest interval - fatigue - lactate accumulation
