Exploring the Dose-Response Relationship between Resistance-Training Volume and Psychophysiological Responses in...

We investigated the effects of different weekly-set progressions on perceptual responses and explored whether muscle thickness (MT) responses were related to perceptual and volume metrics in resistance-trained males. Thirty-one participants were randomly assigned to one of the three groups: a fixed set (FS) group (n = 10), maintaining 22 weekly quadriceps sets; a 4-Set (4S) group (n = 10) and a 6-Set (6S) group (n = 11), increasing by four and six every fortnight, respectively. Training occurred twice weekly for 12 weeks. The session rating of perceived exertion (sRPE) and session feelings of pleasure/displeasure (sFPD) were assessed 15 min post-training, while sRPE-derived metrics (monotony and strain) were analyzed weekly. The sRPE was higher in the FS compared to the 4S group (p = 0.046), while sFPD were higher in the FS compared to the 6S group (p < 0.001). Monotony was lower in the 4S than in other groups (p < 0.001). Strain followed a graded dose-response (6S > 4S > FS, p < 0.001). Overall, there were no meaningful correlations between volume load slopes and MT (r < 0.392) or perceptual responses (r < 0.448). These findings suggest that progressive increases in weekly-set volume influence perceptual responses; however, these responses do not appear to be related to changes in muscle thickness.