Dose–Response Relationship Between Velocity Loss During Resistance Training and Changes in the Squat Force–Velocity Relationship

Abstract

Purpose: This study aimed to compare the adaptations provoked by various velocity loss (VL) thresholds used in resistance training on the squat force–velocity (F–V) relationship. Methods: Sixty-four resistance-trained young men were randomly assigned to one of four 8-week resistance training programs (all 70%–85% 1-repetition maximum) using different VL thresholds (VL0 = 0%, VL10 = 10%, VL20 = 20%, and VL40 = 40%) in the squat exercise. The F–V relationship was assessed under unloaded and loaded conditions in squat. Linear and hyperbolic (Hill) F–V equations were used to calculate force at zero velocity (F0), velocity at zero force (V0), maximum muscle power (Pmax), and force produced at mean velocities ranging from 0.0 to 2.0 m·s−1. Changes in parameters derived from the F–V relationship were compared among groups using linear mixed models. Results: Linear equations showed increases in F0 (120.7 N [89.4 to 152.1]) and Pmax (76.2 W [45.3 to 107.2]) and no changes in V0 (−0.02 m·s−1 [−0.11 to 0.06]) regardless of VL. Hyperbolic equations depicted increases in F0 (120.7 N [89.4 to 152.1]), V0 (1.13 m·s−1 [0.78 to 1.48]), and Pmax (198.5 W [160.5 to 236.6]) with changes in V0 being greater in VL0 and VL10 versus VL40 (both P < .001). All groups similarly improved force at 0.0 to 2.0 m·s−1 (all P < .001), although in general, effect sizes were greater in VL10 and VL20 versus VL0 and VL40 at velocities ≤0.5 m·s−1. Conclusions: All groups improved linear and hyperbolic F0 and Pmax and hyperbolic V0 (except VL40). The dose–response relationship exhibited an inverted U-shape pattern at velocities ≤0.5 m·s−1 with VL10 and VL20 showing the greatest standardized changes.

Neuromuscular adaptations after 12 weeks of light‐ vs. heavy‐load power‐oriented resistance training in older adults

“…In contrast, a previous study involving light‐load plyometric exercise (using a trampoline training device) in older adults has shown meaningful increases in VL FL and VL PA (+8 and +7%, respectively) 13 . The discrepancies between studies may derive from differences in the training device used and some methodological limitations in determining this measure in our study (with large portions of fascicle length lying outside the available field‐of‐view) potentially introducing bias 49 . While it is possible that LL‐PT (which resembles plyometric exercise to a certain extent) would benefit the effectiveness of the stretch‐shortening cycle, it remains to be explored whether LL‐PT or HL‐PT would have greater adaptive potential in this regard.…”

“…13 The discrepancies between studies may derive from differences in the training device used and some methodological limitations in determining this measure in our study (with large portions of fascicle length lying outside the available field-of-view) potentially introducing bias. 49 While it is possible that LL-PT (which resembles plyometric exercise to a certain extent) would benefit the effectiveness of the stretch-shortening cycle, it remains to be explored whether LL-PT or HL-PT would have greater adaptive potential in this regard. Some limitations should be considered when interpreting the present findings.…”

The Acute and Chronic Effects of Implementing Velocity Loss Thresholds During Resistance Training: A Systematic Review, Meta-Analysis, and Critical Evaluation of the Literature

“…Two studies [ 64 , 65 ] used a linear encoder that was not, to our knowledge, validated in the peer-reviewed literature whereas all other studies used valid and reliable methods, equipment, or instruments to evaluate their outcomes of interest. Fourteen studies [ 18 , 25 , 26 , 42 – 45 , 60 , 61 , 70 , 73 , 77 – 79 ] were at a high risk of bias for not having a familiarization session. Four studies [ 69 , 75 , 76 , 80 ] did not provide sufficient information regarding their familiarization sessions and hence, had an unclear risk of bias The rest of the studies provided sufficient information about familiarization session procedures or specifically stated that all participants were accustomed to the study protocols (i.e., performed them in the past).…”

“…5 b). The authors from the several studies [ 25 – 27 , 60 ] suggested that an inverted U-shaped relationship might exist between VL experienced in a set and maximal strength gains. For instance, Pareja-Blanco et al [ 25 , 26 ] reported that once a moderate VL threshold was exceeded (e.g., 20 or 25% VL), further increases in strength gains were not observed.…”

“…The total number of participants pooled across studies was 846 (767 were male and 69 were female). However, upon inspection, it was clear data from the same participants were used in multiple studies [20,[60][61][62]. This reduced the total number of participants to 735 (656 were male and 69 were female).…”