The Influence Of Set Configuration On Total Volume And Velocity Loss In The Back Squat

PURPOSE: The purpose of this study was to examine velocity loss (VL) and relative volume (RV) performed and across four sets of traditional (TR), cluster (CS), and inter-repetition rest (IRR) set configurations. METHODS: Eight (5F/3M) healthy, resistance-trained subjects completed a total of 4 experimental visits separated by ≥48 hrs. Visit 1 consisted of one-repetition maximum (1RM) testing in the back squat. In visits 2-4, subjects completed the TR, CS, or IR conditions in randomized order. Each protocol consisted of a standardized warm-up before completing 4 working sets at 85% of 1RM. Sets 1 (S1) and 2 (S2) consisted of 3 reps, while in sets 3 (S3) and 4 (S4), subjects were asked to complete as reps until an 8 RPE (S3) and ≥ 10 RPE (S4). In the TR condition, participants completed continuous reps with 3 minutes of inter-set rest. In the CS and IRR conditions, individuals were allotted 40 s of intra-set rest and either 3 minutes or 40 s of inter-set rest, respectively, in attempts to time-match the TR. RV (total reps completed × %1RM) and VL ((Fastest rep-last rep)/fastest rep) were collected for all sets. Separate set (S1/S2/S3/S4) × condition (TR/CS/IRR) ANOVAs were run for each dependent variable. RESULTS: There was a significant interaction effect for RV (p = 0.002) in which post-hoc analyses indicated that significantly less RV was completed in TR than CS during S3 (TR: 4.1 ± 1.2 au; CS: 10.1 ± 6.7 au; p = 0.028), and both IRR and CL during S4 (TR: 4.4 ± 1.5 au; CS: 15.6 ± 12.4 au; IRR: 14.0 ± 11.0; p = 0.03-0.032). Significantly more RV was completed during S3 and S4 when compared to both S1 and S2 in all 3 conditions (p = 0.008-0.021), except between S1-S2 and S3 in IRR (S1-S2: 2.6 ± 0 au; S3: 8.6 ± 7.4 au; p = 0.055). There was no significant interaction effect for VL (p = 0.866); however, there was a significant main effect for set (p < 0.001), but not condition (p = 0.163). Post-hoc analyses indicated that when collapsed across condition, VL was significantly greater during S3 (-26.7 ± 11.2%) and S4 (-34.5 ± 9.1%) when compared to S1 (-9.8 ± 3.4%; p < 0.001-0.006) and S2 (-11.7 ± 3.2%; p < 0.001-0.009). There were no other significant differences in VL or RV (p = 0.065-0.676). CONCLUSIONS: The primary finding of this investigation was that despite similar VL across all sets, participants performed more volume in the later sets during CS and IRR when compared to TR.