(26) Validity of Repetition Prediction Equations to Estimate Upper-Body Strength in Trained and Untrained Men

Purpose: The purpose of this study was to cross-validate selected prediction equations to estimate 1RM bench press in trained and untrained men. Methods: Trained (TR, n = 100) and untrained (UT, n = 108) college men volunteered to be measured for 1RM bench press. Trained participants had a minimum of 12 weeks of resistance training typically using a linear periodization program. Participants completed a 1RM test several days before performing RTF with a self-selected weight (RepWt) that allowed between 3 and 10 RTF. Nine widely used prediction equations from the literature were used to estimate 1RM from RepWt and RTF. Results: TR was not significantly different (p >0.12) from UT in age (20.1 ± 1.6 yrs vs 19.8 ±1.4 yrs) and height (178.9 ± 6.1 cm vs 178.5 ± 7.2 cm). TR had significantly greater weight than UT (73.7 ± 12.3 kg vs 69.7 ± 9.0 kg). TR had a significantly greater 1RM (72.0 ± 9.7 kg) and RepWt (59.3 ± 9.0 kg) than UT (60.9 ± 10.7 and 49.1 ± 9.7 kg). There was no significant difference between TR & UT in %1RM (82.4 ± 5.4 vs 81.2 ± 11.2), but UT completed significantly more RTF (7.7 ± 4.4) than TR (5.5 ± 1.9). In the UT group, the Berger equation had a high correlation (r = 0.99) and a small difference between predicted and actual 1RM (-0.4 ± 0.7 kg). In the TR group, the Berger equation again had the lowest difference predicted and actual 1RM (-0.8 ± 0.4 kg). Conclusions: In this sample of TR and UT, it appears that the Berger equation provides the best prediction of 1RM in young men using RepWt and RTF regardless of training background. Practical Applications: Of the array of current 1RM prediction equations, the Berger equation appears to be the best choice until further evaluation on a more diverse population can be done. Acknowledgements: none