Abstract: Nibali, ML, Chapman, DW, Robergs, RA, and Drinkwater, EJ. Influence of rest interval duration on muscular power production in the lower-body power profile. J Strength Cond Res 27(10): 2723–2729, 2013—There is a paucity of evidence-based support for the allocation of rest interval duration between incremental loads in the assessment of the load-power profile. We examined the effect of rest interval duration on muscular power production in the load-power profile and sought to determine if greater rest is required with increasing load (i.e., variable rest interval). Ten physically trained men completed 4 experimental conditions in a crossover balanced design. Participants performed jump squats across incremental loads (0–60 kg) on 4 occasions, with an allocated recovery interval of 1, 2, 3, or 4 minutes. The mean log-transformed power output at each load was used for comparison between conditions (rest intervals). Unloaded jump squats (0 kg) maximized power output at each condition. The maximal mechanical power output was 66.6 ± 6.5 W·kg−1 (1 minute), 66.2 ± 5.2 W·kg−1 (2 minutes), 67.1 ± 5.9 W·kg−1 (3 minutes), and 66.2 ± 6.5 W·kg−1 (4 minutes). Trivial or unclear differences in power output were observed between rest intervals at each incremental load. As expected, power declined per 10 kg increment in load, the magnitude of decrease was 13.9–14.5% (confidence limits [CL]: ±1.3–2.0%) and 13.4–14.6% (CL: ±2.4–3.9%) for relative peak and mean power, respectively, yet differences in power output between conditions were likely insubstantial. The prescription of rest intervals between loads that are longer than 1 minute have a likely negligible effect on muscular power production in the jump squat incremental load-power profile. Practitioners should select either a 1- to 4-minute rest interval to best accommodate the logistical constraints of their monitoring sessions.