Relationship Between the Number of Repetitions and Selected Percentages of One Repetition Maximum in Free Weight Exercises in Trained and Untrained Men

• DOI: 10.1519/r-18195.1
• Publication Date: 2006-12-04T22:03:52Z
• Authors: Tomoko Shimano; William J. Kraemer; Barry A. Spiering; Jeff S. Volek; Disa L. Hatfield; Ricardo Silvestre; Jakob L. Vingren; Maren S. Fragala; Carl M. Maresh; Steven J. Fleck; Robert U. Newton; Luuk P.B. Spreuwe...; Keijo Häkkinen
• Keywords: Adult; Male; Analysis of Variance; Intensity; Physical Education and Training; Weight Lifting; Percentage loading; Environmental and Occupational Health; Sports Therapy and Rehabilitation; Exercise prescription; 2739 Public Health; 796; 03 medical and health sciences; 2732 Orthopedics and Sports Medicine; 0302 clinical medicine; Humans; 3612 Physical Therapy; Muscle, Skeletal; Weight training

Resistance exercise intensity is commonly prescribed as a percent of 1 repetition maximum (1RM). However, the relationship between percent 1RM and the number of repetitions allowed remains poorly studied, especially using free weight exercises. The purpose of this study was to determine the maximal number of repetitions that trained (T) and untrained (UT) men can perform during free weight exercises at various percentages of 1RM. Eight T and 8 UT men were tested for 1RM strength. Then, subjects performed 1 set to failure at 60, 80, and 90% of 1RM in the back squat, bench press, and arm curl in a randomized, balanced design. There was a significant (p < 0.05) intensity x exercise interaction. More repetitions were performed during the back squat than the bench press or arm curl at 60% 1RM for T and UT. At 80 and 90% 1RM, there were significant differences between the back squat and other exercises; however, differences were much less pronounced. No differences in number of repetitions performed at a given exercise intensity were noted between T and UT (except during bench press at 90% 1RM). In conclusion, the number of repetitions performed at a given percent of 1RM is influenced by the amount of muscle mass used during the exercise, as more repetitions can be performed during the back squat than either the bench press or arm curl. Training status of the individual has a minimal impact on the number of repetitions performed at relative exercise intensity.