Correlations Between Resistance Exercise Repetitions Achieved at 60% and 80% 1rm Load in Female Subjects

To determine the appropriate load for resistance training (RT), exercise professionals (EPs) commonly have clients complete one repetition maximum testing (1RM). Then, submaximal loads can be easily calculated for RT sessions. A higher load (approximately 80% 1RM) is chosen if lower repetitions (reps) are desired (≈ 10 reps) and a lower load (approximately 60% 1RM) is chosen if higher reps are desired (≈ 20 reps). However, the number of reps generated (at both low and high loads) varies quite dramatically in standard populations. It is important to determine if there are strong relationships between the number of reps generated at lower and higher loads. The hypothesis is that individuals tend to perform similarly at different loads (i.e. generate above average reps at both loads or below average reps at both loads). However, this topic has not been thoroughly studied. PURPOSE: Determine correlations between RT reps achieved at 60% 1RM load and 80% 1RM load. This will help us understand if the number of reps generated at lower loads predicts the number or reps generated at higher loads. METHODS: Participants were 19 college-aged (25 ± 4.3 years) females with a minimum of 2 months RT experience. Three exercise sessions were completed under the supervision of certified EPs. For session one, 1RM testing was completed. For sessions two and three, participants completed as many reps as possible for 60% 1RM or 80% 1RM (load and order was randomized) for 8 cam-mediated variable resistance training exercises. For all 8 exercises, Pearson correlation was used to assess the strength of the relationship between the two loads. RESULTS: The reps generated at 60% 1RM and 80% 1RM and correlations between the two were determined for the following 8 exercises: bench press (8.2±3.4 reps to 18.3±4.2 reps; r = 0.51), leg press (17.9±5.0 reps to 37.3±15.9 reps; r = 0.63), shoulder press (7.8±2.5 reps to 13.6±3.5 reps; r = 0.59), pull-down (10.3±2.1 reps to 24.1±8.3 reps; r = 0.05), knee extension (11.4±4.7 reps to 17.3±5.8 reps; r = 0.71), knee flexion (12.4±4.5 reps to 23.4±6.7 reps; r = 0.74), elbow extension (12.5±5.0 reps to 23.0±10.3 reps; r = 0.63), and elbow flexion (9.9±5.4 reps to 17.3±6.4 reps; r = 0.86). CONCLUSIONS: EPs should understand that correlations between repetitions achieved at different loads tend to be moderate.