Acute Metabolic, Physiological, and Perceptual Responses to Different Set and Rep Schemes in the Back Squat

The purpose of this study was to examine the acute effects of ecologically valid schemes of sets and repetitions in the back squat during the bout and into recovery. Such understanding is expected to contribute to knowledge of the strength-endurance continuum and differential responses to various training emphases in practical settings. Eleven participants completed back squat protocols consisting of a warm-up followed by either 3 x 2 at 90% of 1RM, 3 x 5 at 82.5% of 1RM, and 3 x 10 at 62.5% of 1RM in a randomized and counterbalanced design. VO2, heart rate (HR), lactate, and RPE were collected at baseline, during exercise, and into 10 minutes of recovery. A mixed ANOVA using linear mixed-effect model was used to examine the effects of protocol, time, and sex for VO2 and HR. A repeated measures ANOVA was used to examine the effects of protocol and time for lactate. RPE was analyzed using an ordinal mixed effect model for the effects of protocol and time. The critical alpha was set at 0.05. For HR, lactate, and VO2, post hoc testing was performed using either Tukey’s HSD (pairwise comparisons) or Scheffe’s adjustment (simple contrasts), and the associated Cohen’s d was calculated with 95% confidence intervals. There were statistically significant main effects of condition and time for lactate, VO2, and heart rate (p ≤ 0.05). There was a statistically significant effect of time for RPE (p ≤ 0.05). The post hoc pairwise comparisons revealed that lactate was statistically higher in the tens compared to sets of fives and twos across all time points measured but rest (p ≤ 0.05). The physiological and perceptual differences between conditions appear negligible by five minutes into recovery with the exception of lactate values. Sets of ten are likely to produce the highest glycolytic stress, however, as a possible result of greater intensity in the sets of five, the peak VO2 and HR responses may be similar. Practitioners looking to induce large amounts of metabolic stress during training sessions to develop anaerobic capacity should opt for higher repetition sets, however, these training sessions may lead to higher perceived exertions.