2005 Volume 50 Issue 4 Pages 425-436
The present study investigated the profiles of muscular strength and endurance characteristics in individuals based on two types of evaluation, and attempted to obtain a fundamental guideline for determining training objectives of dynamic resistance training with the ultimate aim of increasing the one-repetition maximum (1RM). Thirty-six male college and graduate students with experience in various sports participated. The subjects performed knee extension exercise, and maximal isometric strength (Isom.max), 1RM and the numbers of repetitions loaded at 90%, 70% and 50% 1RM (N_<90>, N_<70>, N_<50>) were measured. To evaluate the characteristics of muscular endurance, two original indices, N_<total> (total number of repetitions: N_<90>+N_<70>+N_<50>), and I-E slope (Intensity-Endurance slope: the form of the relationship between relative load and number of repetitions) were used. The subjects were divided into four groups based on their strength and endurance performance, i.e. 1RM and N_<total>, or 1RM and I-E slope (SE: high strength-high endurance, Se: high strength-low endurance, sE: low strength-high endurance, se: low strength-low endurance). The major findings were: (1) The number of repetitions was largest at 50% 1RM among the intensities used, and decreased significantly with the increase in relative load (P<0.01). (2) There was a significant negative correlation between 1RM and N_<total> (P<0.01). (3) There was a significant positive correlation between N_<total> and I-E slope (P<0.01). (4) N_<total> and I-E slope possibly represent different physiologic factors of muscular endurance, because unlike N_<total>, I-E slope did not correlate with 1RM. (5) The profiles of muscular strength and endurance in each individual can be appropriately evaluated by using the relationship between either 1RM and N_<total> or that between 1RM and I-E slope. The results suggest the importance of evaluating the profiles of muscular strength and endurance in each individual to determine the primary training objective of a dynamic resistance training program.