Accuracy and reliability of perception of bar velocity loss for autoregulation in resistance exercise

BackgroundThe perception of bar velocity loss (PVL) can be used as an alternative method for autoregulating intraset repetitions during velocity-based training. This study analyzed the accuracy and reliability of the PVL as a method to autoregulate the intraset repetitions using a moderate velocity loss (VL) threshold (15–30%).MethodsA total of 22 resistance-trained men were familiarized with the PVL in a single session. Test–retest was performed in two sessions 1 week apart, in which participants completed three sets of bench press and back squat at 40, 60, and 80% 1 repetition maximum (1RM). Participants stopped the sets when they reached a moderate VL zone using their PVL. Accuracy was assessed by analyzing whether the mean VL (actual) and the lower and upper limits of the confidence interval (CI) (95%) of each set were within the established VL range and quantifying the relative frequency of correctly interrupted sets. Test–retest reliability was examined by the intraclass correlation coefficient and coefficient of variation.ResultsPVL showed acceptable accuracy in both exercises at 60 and 80% 1RM (50–65% success rate) and retest for all loads (53–76% success rate). Similar PVL percentages were observed between most of the sets for the test and retest ( p > 0.05). Accuracy improved during the retest, especially for bench press (40% 1RM) and back squat (40 and 80% 1RM). PVL was not reliable in the test–retest comparison.ConclusionPVL can be a strategy with acceptable accuracy to autoregulate the intraset repetitions in a moderate zone (VL15–30%), but its reliability does not appear satisfactory after one familiarization session.