Relationship Between Repetitions and Selected Percentages of the One Repetition Maximum in Healthy Children

The purpose of this study was to evaluate the relationship between repetitions and selected percentages of the one repetition maximum (RM) in apparently healthy children. The 1 RM strength was measured on 13 boys and eight girls (mean age 10.4 ± 1.2 years) on the Heartline chest press and the Nautilus leg press exercises. Subsequently, subjects were tested to determine the maximum number of repetitions that could be performed to volitional fatigue at 50% and 75% of their 1 RM for each exercise. The results for the trials on the leg press and chest press indicate that at 50% 1 RM, the subjects performed 87.2 ± 56.5 and 39.2 ± 19.4 repetitions, respectively, whereas at 75% 1 RM, the subjects performed 18.2 ± 11.0 and 13.4 ± 4.3 repetitions, respectively. As the percent 1 RM increased, it is not surprising that the number of repetitions performed significantly decreased (p < 0.05). However, the number of repetitions performed at 50% 1 RM on the leg press was significantly greater (p < 0.05) than at the same intensity on the chest press, suggesting that the number of repetitions performed at a given intensity may not be same for all exercises. Although additional study is warranted, these findings suggest that progressive resistive strengthening programs should be prescribed with a RM load as opposed to a percentage of the 1 RM.