Acute Effect of Fixed vs. Self-Selected Rest Interval Between Sets on Physiological and Performance-Related Responses

Area of Science:

• Sports Science
• Exercise Physiology
• Strength and Conditioning

Background:

• Previous research on self-managed vs. fixed rest in lower-limb strength training yielded inconclusive results.
• Controversies exist regarding the optimal rest period strategy for trained individuals.
• This study addresses the ambiguity by comparing rest protocols in experienced trainees.

Purpose of the Study:

• To investigate the effects of self-managed rest versus fixed rest on athletic performance.
• To analyze the impact on mean propulsive velocity (MPV), velocity loss, and muscle oxygen saturation (SmO2).
• To compare total rest time between the two rest conditions in trained subjects.

Main Methods:

• Thirteen trained subjects (≥1 year experience) were divided into self-selected rest (SR) and fixed rest (FR) groups.
• Participants performed five sets of four repetitions of back squats at 80% of one-repetition maximum (1RM).
• MPV was measured using a linear position transducer, and SmO2 with near-infrared spectroscopy.

Main Results:

• A significant difference in rest time was observed between the first and second sets (SR: 97.29s vs. FR: 120s).
• No significant differences were found between groups for MPV, velocity loss, or SmO2.
• Performance and physiological markers remained comparable across both rest conditions.

Conclusions:

• Both fixed and self-selected rest periods are equally effective for trained individuals.
• The choice between rest protocols should align with athlete preferences and specific training goals.
• This finding offers flexibility for coaches and athletes in optimizing training strategies.