Feasibility of Velocity Loss-Based Volume Prescription During Constant-Load and Chain-Based Smith Machine Back Squats

The goal of this observational study was to evaluate the feasibility of percentage of velocity loss (%VL)-based approaches for prescribing training volume during constant-load and chain-based Smith machine back squats. The study aimed to answer whether %VL can be expressed as the maximum number of repetitions (%Rep) in constant-load and chain-based Smith machine squats. Twenty-six resistance-trained men performed repetitions-to-failure tests under variable (VRT) and constant resistance training (CRT). The %Rep attained before reaching different levels of effort were compared between VRT and CRT across various loads and sessions. Furthermore, this study evaluated the influence of different factors on the predictive accuracy of the %Rep-%VL relationships. These findings will provide evidence-based evidence in prescribing and monitoring intra-set volume.

Inclusion Criteria: * at least 1 year of resistance training experience, performing back squats at least once per week. * proficiency in the Smith machine back squat executed at maximal intended velocity. * a constant-load 1RM of ≥ 1.5 times their body mass. * no reported musculoskeletal injuries in the past three months. Exclusion Criteria: * Voluntary withdrawal or injury. * Not satisfied with inclusion label.