Perception of bar velocity in resistance training: Accuracy levels within and between exercises

Abstract

Velocity-based training is a method used to monitor resistance-training programs based on repetition velocities measured with tracking devices. Since velocity measuring devices can be expensive and impractical, trainee’s perception of velocity (POV) may be used as a possible substitute. Here, 20 resistance-trained males first completed 1RM tests in the bench-press and squat. Then, in three counterbalanced sessions, participants completed four sets of eight repetitions in both exercises using 60%1RM (two-sessions) or 70%1RM. Starting from the second repetition, participants reported their POV of each repetition as a percentage of the first repetition. Accuracy was calculated as the difference between POV and actual-velocity measured with a linear-encoder. Two key findings emerged. First, the absolute error in both exercises was ~5.8 percentage-points in the second repetition, and it increased to 13.2 and 16.7 percentage-points by the eighth repetition, in the bench-press and squat, respectively. Second, participants were 4.2 times more likely to underestimate velocity in the squat. Given the gradual increments in the absolute error, POV may be better suited for sets of fewer repetitions (e.g., 4-5) and wider velocity-loss threshold ranges (e.g., 5-10%). Given the systematic underestimation error in the squat, a correction factor may increase POV accuracy in this exercise.

Perception of changes in bar velocity as a resistance training monitoring tool for athletes

“…A pre-post within-subject design was used to investigate (i) the accuracy levels of PCV in the barbell squat exercise performed in a Smith-Machine (Technogym Equipment, Barcelona, Spain) among professional soccer players familiar with VBT; (ii) examine if, and to what extent, PCV accuracy can be improved among this cohort when receiving augmented feedback on the extent and direction of their errors. Whereas in Sindiani et al 12 participants lifted fixed training loads (e.g., 60% and 70% of 1RM), in the present study athletes lifted their individual OPL. This decision was based on the fact that the recruited athletes routinely performed the squat exercise loaded with OPL while following a similar training volume configuration (i.e., sets × repetitions).…”

“…In contrast to Sindiani et al's study 12 in which an analysis of the propensity of a unidirectional error (i.e., either under-or over-estimating the bar velocity) was reported in the main text, in the current study we decided to present this analysis as supplementary material because we did not find any theoretical or practical value of this analysis to the field (see online supplement).…”

“…Second, there is a need to investigate to what extent accuracy levels can be improved. The fact that subjects reduced the absolute error in the second 60%1RM session in the study by Sindiani et al 12 suggests that practice can enhance accuracy levels. Importantly, the observed improvement occurred despite the fact that subjects were not provided with feedback on ACV.…”

“…Second, the directional error, defined as the likelihood of over-or underestimating ACV. Sindiani et al 12 observed three key findings. First, across sessions and sets, the absolute error was ~5.8 percentage-points in both exercises in the second repetition and increased to 13.2 and 16.7 percentage-points by the eighth repetition in the bench-press and squat, respectively.…”

“…Recently, Sindiani et al 12 examined the accuracy levels of trainee's perception of changes in bar velocity (PCV) in comparison to actual bar velocity (ACV) measured with an LPT.…”