Evaluation of Load-Velocity Relationships and Repetitions-to-Failure Equations in the Presence of Male and Female Spotters

• Published in: Journal of strength and conditioning research Vol. 34; no. 9; pp. 2427 - 2433
• Main Authors: Nickerson, Brett S., Williams, Tyler D., Snarr, Ronald L., Garza, Jessica M., Salinas, Gilberto
• Format: Journal Article
• Language: English
• Published: United States Journal of Strength and Conditioning Research 01-09-2020; Copyright by the National Strength & Conditioning Association; Lippincott Williams & Wilkins Ovid Technologies
• Subjects: Adult; Cross-Over Studies; Female; Humans; Male; Muscle Strength - physiology; Muscle, Skeletal - physiology; Predictions; Regression analysis; Resistance Training - methods; Sex Factors; Strength training; Studies; Velocity; Women; Young Adult
• ISSN: 1064-8011; 1533-4287
• DOI: 10.1519/JSC.0000000000003731

ABSTRACTNickerson, BS, Williams, TD, Snarr, RL, Garza, JM, and Salinas, G. Evaluation of load-velocity relationships and repetitions-to-failure equations in the presence of male and female spotters. J Strength Cond Res 34(9)2427–2433, 2020—The purpose of this study was 2 fold(a) to determine whether differences in mean concentric velocity (MCV), repetitions-to-failure (RTF), measured 1 repetition maximum (1RM), and 1RM prediction methods vary between lifter and spotter sex and (b) determine the accuracy of velocity-based 1RM (MCV1RM) and repetitions-to-failure-based 1RM (RTF1RM) prediction equations in the presence of either a male or female spotter. Twenty resistance-trained individuals (50% men) participated in this study. The initial 2 visits involved measuring 1RM for the bench press with a male or female spotter. Visits 3 and 4 required subjects to lift loads at 30 (5-repetitions), 50 (5-repetitions), and 70% 1RM (RTF) in the presence of a male or female spotter. Velocity-based 1RM was determined through individual regression equations using the submaximal loads (MCV30, MCV50, and MCV70). Repetitions-to-failure-based 1RM was determined through the RTF at 70% 1RM using Wathen (Wathen1RM), Mayhew (Mayhew1RM), and Epley (Epley1RM) equations. There were significant interactions when assessing Wathen1RM and Mayhew1RM (p < 0.05). Female lifters produced significantly higher estimated 1RM values during the male spotter condition using Wathen1RM and Mayhew1RM than the female spotter condition (p = 0.032 and 0.033, respectively). MCV1RM and Epley1RM produced smaller mean differences than Wathen1RM and Mayhew1RM when compared with measured 1RM. However, MCV1RM produced the largest standard error of estimate, whereas Epley1RM produced the lowest values. Epley1RM should be used over MCV1RM, Wathen1RM, and Mayhew1RM when loads up to 70% 1RM are implemented. Also, spotter sex only seems to impact female lifters when using the RTF1RM prediction equations of Wathen1RM and Mayhew1RM.