Acute Kinetic and Kinematic Responses to Rest Redistribution With Heavier Loads in Resistance-Trained Men

Abstract

Chae, S, Bailey, CA, Hill, DW, McMullen, SM, Moses, SA, and Vingren, JL. Acute kinetic and kinematic responses to rest redistribution with heavier loads in resistance-trained men. J Strength Cond Res 37(5): 987-993, 2023-The purpose of this study was to examine mechanical responses to rest redistribution with heavier loads (RR + L) in resistance-trained men. Eight men (23.0 6 4.8 years, 1.76 6 0.06 m, 78.5 6 8.6 kg, back squat [BS] one-repetition maximum [1RM] of 138.7 6 27.9 kg) completed 2 BS exercise sessions in a counterbalanced and a randomized order; RR + L: 4 sets of (2 3 5) repetitions with 90-second interset rest and 30-second intraset rest using 75% BS 1RM and traditional sets (TS): 4 sets of 10 repetitions with 120-second interset rest using 70% BS 1RM. During the concentric phase, mean force ( xF), velocity ( xV), and power ( xP) were collected for each repetition using a linear position transducer and analyzed the first 3 sets. Compared with TS, RR + L resulted in significantly greater xF (1820 6 260 N vs. 1753 6 248 N; p , 0.001; g 5 0.25) and lower xV (0.47 6 0.07 m•s 21 vs. 0.50 6 0.09 m•s 21 ; p 5 0.005; g 5 20.35). However, no significant difference in xP (836 6 165 W vs. 871 6 197 W; p 5 0.082; g 5 20.18) was found between RR + L and TS. In conclusion, the lack of difference in xP might be the result of the combination of greater xF and lower xV for RR + L compared with TS. Therefore, practitioners may consider using RR + L to augment xF without compromising xP and increasing total rest time. However, given the approximate 4% difference in xF, the effect of RR + L training on chronic strength adaptation is expected to be small.

Acute Physiological and Perceptual Responses to Rest Redistribution With Heavier Loads in Resistance-Trained Men

“…In the previous studies, RR attenuated various acute fatigue indices (e.g., BL, RPE, HR, and percent decline in velocity and power responses) when compared with TS (1,13,14,27,28,33). In this study including the companion article (3), all above-mentioned fatigue indices were not significantly different with trivial ( g = 0.0–0.2) to small ( g = 0.2–0.6) effect size estimates. The equivocal findings of various fatigue responses between previous research (1,13,14,27,28,33) and this study are likely because of the addition of 5% BS 1RM (and approximately 7% of greater volume load).…”

“…In conclusion, this study expands on acute kinetic and kinematic responses reported in the companion article (3) by elucidating acute physiological and perceptual responses. Apart from the percent decline and maintenance in velocity and power (3), other fatigue indices such as BL, RPE, and HR did not significantly differ between RR + L and TS with the small ( g = −0.22), trivial ( g = 0.14), and trivial ( g = −0.08) effects, respectively, when all time points and sets are averaged. Thus, it may be suggested that the manipulation of set structures attenuates these fatigue responses because RR + L completed greater volume load (approximately 7%).…”

“…Regarding force output and BL, GH, and TT responses as training stimuli, RR + L augmented mean force (approximately 4%) (3) while no significant differences were reported in the BL, GH, and TT responses between RR + L and TS with the small ( g = −0.22), trivial ( g = −0.15), and trivial ( g = −0.09) effects, respectively, when all time points are averaged. Therefore, especially for physiological responses, the degree of increase in the volume load for RR + L seems to be insufficient to increase the BL, GH, and TT responses.

Practical Applications

Based on the results of this study including the companion article (3), RR + L might still be an alternative BS training protocol to TS for lower-body strength adaptation because it allows for increased mean force without decreasing the BL, GH, and TT responses as training stimuli. While the use of RR + L can increase volume load to be completed, various acute fatigue responses might not be increased accordingly based on the results of the BL, RPE, HR, WBC, LYM, MONO, and GRAN responses.

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“…First, Second, and Third Visits. This section provides a brief description of the procedures; full details of procedures are provided in the companion article from the same overall project (3). The first visit consisted of an anthropometric, familiarization, and BS 1RM measurement.…”

“…In the companion article (3), we discussed the studies that elucidated mechanical responses between rest redistribution (RR) and traditional sets (TS) and how these responses can be affected by additional loads during the RR with heavier loads (RR + L) protocol. Apart from the mechanical responses, multiple researchers have focused on examining metabolic (10,14,27,30,31,33,39) and perceptual (1,7,16,18,19,26,27,33,39) responses to RR.…”