Effects Of Multiple Loads Within A Set Of Resistance Training On Muscle Strength And Power

PURPOSE: Changes in power performance due to resistance training are known for load-specific response. The present study examines the effects of load reduction within a set on power performance and muscle strength compared to different load protocols of the same volume. METHODS: Thirty-six trained men (one subject dropped out) were randomly assigned to one of three resistance training groups with volume matched: high-load, HL (n = 11); reduction-load, RL (n = 12); low-load, LL (n = 12). Exercise training was performed twice per week for 3 weeks. Resistance training for each group comprised the following: HL, three sets of five repetitions (reps) at 85% one-rep maximum (1RM); RL, three sets of two reps at 85% 1RM, two reps at 75% 1RM, and two reps at 55% 1RM; and, LL, three sets of eight reps at 55% 1RM. The rest interval between sets for all groups was 3 min. The exercise consisted of free weight bench press (BP). Participants performed a 1RM test and maximal isometric muscle strength (maximal voluntary contraction, MVC; rate of force development, RFD, at baseline and after each training program using the BP. Blood lactate concentrations were measured before and after first session of exercise. RESULTS: Blood lactate concentrations were significantly higher in HL than in RL and LL after each exercise, p = 0.007 and 0.003, respectively. 1RM and MVC changed before (6.0 ± 12.2% for LL, 5.7 ± 6.1% for HL, 3.3 ± 7.6% for RL, p = 0.006) and after1RM (2.0 ± 3.2% for LL, 4.3 ± 3.2% for HL, 4.7 ± 4.2% for RL, p > 0.001). There was an interaction in the RFD results (p = 0.009). One-way analysis of variance (ANOVA) results showed higher changes for HL compared to LL and RL (p = 0.02, p = 0.03). CONCLUSION: Our results show that load reduction training is associated with lower blood lactate concentration and similar changes in muscle strength compared with high load. However, only high load group shows significant RFD increase.