Inter-set Occlusion Reduces Volume And Increases Fatigue Without Affecting Acute Recovery

PURPOSE: To examine the effect of inter-set occluded rest on the recovery of force production following repeated fatiguing dynamic exercise. METHODS: 6 males and 5 females (22 ± 1 yr) performed a one-repetition maximum (1RM) and 3 sets of single-limb leg extension at 60% 1RM, with un-occluded (CON) or occluded (OCC) 1-min rest between sets, on 3 separate days. Nine repetitions were completed in set 1, and sets 2 and 3 were completed to failure. Maximal voluntary isometric contractions (MVIC) were performed immediately before and after each rest period. Rest after set 3 was un-occluded for CON and OCC. A 2 (CON, OCC) x 3 (set 1 rest, set 2 rest, set 3 rest) repeated measures ANOVA was used to determine the %Δ MVIC from the beginning to end of inter-set rest. Paired samples t-tests were used to determine repetitions completed (sets 2 and 3) and 1-min MVIC (%max) recovery following set 3 between OCC and CON. α < 0.05. RESULTS: Less repetitions were completed for OCC than CON in sets 2 (OCC: 1 ± 1, CON: 6 ± 2, p < 0.001) and 3 (OCC: 0 ± 0, CON: 2 ± 1, p < 0.001). There was less recovery with OCC than CON after set 1 rest (OCC: -11.5 ± 8.8%, CON: 4.2 ± 6.7%, p < 0.001) and set 2 rest (OCC: -13.7 ± 10.3%, CON: 3.6 ± 8.5%, p < 0.001). Following un-occluded set 3 rest, OCC (10.7 ± 8.9%) demonstrated greater recovery than CON (5 ± 6.8%, p = 0.019). However, MVIC did not differ between OCC (64.3 ± 9.5%) and CON (68.9 ± 6.6%) at 1-min post-exercise (p = 0.165). CONCLUSION: As demonstrated by reduced MVIC recovery, inter-set OCC exacerbated the influence of exercise-induced fatigue, even when less repetitions were performed in each set compared to CON. Despite experiencing additional fatigue from OCC rest, MVIC for the OCC condition reached a similar level as CON within 1-min of un-OCC rest. This suggests inter-set OCC increases the fatigue stimulus, likely through metabolite accumulation, and does not impede acute post-exercise recovery.