Comparison Between Isotonic 1 Repetition Maximum Measurement With Isometric Muscle Strength Testing In Healthy Females

1 repetition maximum (RM) and Maximum Voluntary Contraction (MVC) with digital dynamometer are popular method of measuring muscle strength. The types of muscle contraction involved in both are different, 1RM involves isotonic muscle contraction (ITMC) and MVC with digital dynamometer involves isometric muscle contraction (IMMC). There are several risks involved in measurement of 1RM, such as delayed onset muscle soreness (DOMS) and unsafe for pathological joints etc, this can be reduced if IMMC is used in measuring strength. Though both cannot be equated as they are different type of contraction, therefore the purpose of this study was to compare between 1RM measurement and isometric MVC using a digital hand-held dynamometer in healthy females. Twenty nine young females (mean age = 20.77 ± 1.28) without any weight training experience (mean BMI = 20.43 ± 1.85) volunteered for the study. It was a crossover trial where 48 hours of rest period was given between each measurement technique. The result showed moderate correlations (r = 0.365-0.847) between 1RM and MVC. A simple linear regression analysis revealed a significant estimated regression equation for dominant and non-dominant hands. \[Dominant, Y=0.391x + 1.472; Non-Dominant, Y=0.251x + 2.629; (Y: 1RM, x: Isometric)\] with low standard error of estimation value of (Dominant, 0.74; Non-dominant, 0.80). The result also showed no significant difference between these derived equations and Brzycki 1RM prediction equation. Therefore, it was concluded that both prediction equations can be used interchangeably to predict the strength of a person, and thus IMMC can be used to predict 1RM in healthy females.