Abstract
Background: The Keiser 10-rep leg press test protocol employs short inter-repetition rest intervals (2-38 s), raising concerns as to whether athletes perform optimally. Objectives: The aim of this study was to compare the results of the standard Keiser protocol with an identical protocol modified to include a significantly longer inter-repetition rest intervals and to evaluate whether these effects differed between men and women. Methods: A total of 30 athletes (age 17.1 ± 0.9 years, height 177.8 ± 8.8 cm, and body mass 71.9 ± 11.3 kg) performed three separate tests (total of ~900 repetitions) in a Keiser A420 leg press machine, separated by 4 to 8 days. Test day 1 included a 1RM test followed by a 10-repetition force-velocity test with a standard rest intervals. Test days 2 and 3 involved the same test, with either standard short rest intervals or fixed 3 min inter-repetition rest intervals. Results: Increasing inter-repetition rest intervals significantly improved V(0) and P(max) for men and V(0) and FV(slope) for women. The benefits of longer rest were notably more pronounced in men, particularly at light to moderate loads, where standard Keiser rest intervals are short (2-9 s). However, extending rest intervals beyond approximately 30 s, as applied at higher loads, provided no additional advantages. Conclusions: Longer rest intervals improved force-velocity metrics more in men than women, with the effect being most pronounced at light to moderate loads where standard protocols utilize short rest intervals (2-9 s). These findings suggest that women recover faster than men under these conditions. However, extending rest beyond 30 s at higher loads provides no additional benefits and is counterproductive at maximal loads.