The influence of direct supervision of resistance training on strength performance

Purpose: The purpose of this study was to compare changes in maximal streng th, power, and muscular endurance after 12 wk of periodized heavy-resistanc e training directly supervised by a personal trainer (SUP) versus unsupervi sed training (UNSUP). Methods: Twenty moderately trained men aged 24.6 +/- 1.0 yr (mean +/- SE) were randomly assigned to either the SUP group (N = 10 ) or the UNSUP group (N = 8). Both groups performed identical linear period ized resistance training programs consisting of preparatory (10-12 repetiti ons maximum (RM)), hypertrophy (8 to IO-RM), strength (5 to 8-RM), and peak ing phases (3 to 6-RM) using free-weight and variable-resistance machine ex ercises. Subjects were tested for maximal squat and bench press strength (I -RM), squat jump power output, bench press muscular endurance, and body com position at week 0 and after 12 wk of training. Results: Mean training load s (kg per set) per week were significantly (P < 0.05) greater in the SUP gr oup than the UNSUP group at weeks 7 through 11 for the squat, and weeks 3 a nd 7 through 12 for the bench press exercises. The rates of increase (slope ) of squat and bench press kg per set were significantly greater in the SUP group. Maximal squat and bench press strength were significantly greater a t week 12 in the SUP group. Squat and bench press 1-RM, and mean and peak p ower output increased significantly after training in both groups. Relative local muscular endurance (80% of 1-RM) was not compromised in either group despite significantly greater loads utilized in bench press muscular endur ance testing after training. Body mass, fat mass, and fat-free mass increas ed significantly after training in the SUP group. Conclusion: Directly supe rvised, heavy-resistance training in moderately trained men resulted in a g reater rate of training load increase and magnitude which resulted in great er maximal strength gains compared with unsupervised training.