Evaluation of a 2-Load Prediction Equation to Predict 1RM Bench Press in Football Players


Jerry L. Mayhew1, William F. Brechue2, Bryan Mann3, J. Jay Dawes4

1Truman State University, Kirksville, Missouri, 2Physiology Department, A. T. Still University of Health Sciences, Kirksville, Missouri, 3University of Miami, Miami, FL, 4Oklahoma State University, Stillwater, OK

Repetitions-to-fatigue (RTF) equations are popular for estimating one-repetition maximum (1RM) bench press performance. Most of these equations have used a single submaximal load in the 70-90% range to predict 1RM. However, the efficacy of using a 2-load approach, as suggested by Brzycki, has received little attention. This technique extrapolates the slope of the 2-load-to-repetition relationship to estimate 1RM. The 2-load approach has not been compared to single-load equations to determine its accuracy for estimating 1RM in athletes. PURPOSE: To compare the accuracy of 1-load and 2-load equations to predict 1RM bench press in college football players. METHODS: NCAA Division-II players from 3 schools (n = 157) volunteered to participate during off-season resistance training. Players were grouped as linemen (n = 80; age = 19.5 ± 1.2 yrs, height = 184.7 ± 6.3 cm, weight = 107.8 ± 18.5 kg) and backs (n = 77; age = 19.6 ± 1.4 yrs, height = 182.1 ± 6.6 cm, weight = 92.3 ± 16.6 kg). Each player performed RTF in the 3-5RM and 7-10RM ranges on two separate days within the same week. The week following RTF performances, each player performed a 1RM using the standard touch-and-go method. 1RM predictions were constructed using several 1-load equations, the original 2-load 1repetition reduction equation, and a newly developed 2-load no-repetition reduction approach. RESULTS: The %1RM in the 3-5RM range was not significantly different between backs (90.2 ± 2.5%) and linemen (89.8 ± 2.4%). Likewise, %1RM in the 7-10RM range was not significantly different between backs (80.0 ± 4.0%) and linemen (79.9 ± 3.8%). The original 1load prediction for both 3-5RM loads (133.2 ± 24.0 kg) and 7-10RM loads (134.6 ± 23.8 kg) significantly underpredicted 1RM (136.5 ± 24.8 kg). The 2-load equation with a 1-repetition reduction (133.0 ± 24.4 kg) also significantly underpredicted 1RM. A new no-repetition reduction approach accurately predicted 1RM (136.5 ± 25.2 kg) to within ±5.0% in 79% of the players. The new no-reduction equation had no bias and an acceptable 95% LoA (-12.0 to 12.0 kg). CONCLUSION: A modified version of a two-load RTF prediction equation without a repetition reduction appears to offer a more accurate estimate of 1RM bench press in football athletes than previous 1-load equations or a 2-load 1-repetiton reduction equation.

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