Using absolute and relative muscle endurance to estimate maximal strength in young athletes.

PURPOSE The purpose of this study was to evaluate the effectiveness of repetitions to fatigue (RTF) using absolute and relative muscle-endurance performances to estimate 1-repetition-maximum (1-RM) bench-press performance in high school male athletes. METHODS Members of high school athletic teams (n = 118, age = 16.5 +/- 1.1 y, weight = 82.7 +/- 18.7 kg) were tested for 1-RM bench press and RTF with an absolute load of 61.4 kg and a relative load that produced 7 to 10 RTF (7- to 10-RM). All participants had completed a minimum of 4 wk of resistance training before measurement. RESULTS All 7- to 10-RM-prediction equations had higher correlations between predicted and actual 1-RM (r > .98) than the 61.4-kg absolute-load equation (r = .95). Despite the high correlations, only 3 of 11 equations produced predicted values that were nonsignificantly different from actual 1-RM. The best 7-to 10-RM equation predicted 65% of the athletes'performances within +/-4.5 kg of their actual 1-RM. The addition of simple anthropometric dimensions did not increase the validity correlations or decrease the prediction errors. CONCLUSION The 7- to 10-RM method can provide an accurate method of estimating strength levels for adjusting loads in a training program and is more accurate for predicting 1-RM bench press in high school athletes than the 61.4-kg repetition method.