Association Of Muscle Biomechanical Properties With Army Combat Fitness Test Performance In ROTC Cadets.

Abstract

Myotonometry is a reliable, non-invasive method to assess muscle stiffness, tone, and elasticity and has demonstrated significant associations with physical performance. However, no studies have investigated the predictive relationship of myotonometric parameters with Army Combat Fitness Test (ACFT) performance. Such information will help determine if myotonometry can serve as an effective screening method to identify muscular deficits in soldiers who demonstrate poor combat fitness. PURPOSE: To explore the predictive value of myotonometrics of the erector spinae (ES), vastus lateralis (VL), and biceps femoris (BF) muscles with ACFT performance. METHODS: Following ACFT performance, myotonometric measures were recorded in 38 cadets (Age 21.6 + 3.78; 26% female) with a handheld myotonometer (MyotonPRO; Myoton AS, Tallinn, Estonia) in the ES, BF, and VL muscles. Measures were collected under passive, non-weightbearing conditions (prone: ES and BF; supine: VL). Anthropometrics were also collected for each participant. Bivariate associations were examined between predictive factors and ACFT performance using Pearson product correlation analysis. Multivariate relationships were then evaluated using stepwise multiple linear regression. RESULTS: Bivariate correlation analysis identified 7 variables that were significantly associated with ACFT performance [fat-free mass index (FFMI), r = .629, p < .001; VL tone, r = .661, p < .001; ES stiffness, r = .394, p = .015; ES tone, r = .406, p = .011; BF stiffness, r = .509, p = .001; BF elasticity, r = .358, p = .027]. Three of the 7 variables were retained in the multiple linear regression model (VL tone, BF elasticity, and FFMI) predictive of ACFT performance, resulting in R2 of 0.672, with VL tone being the most significant contributor. CONCLUSION: VL tone, BF elasticity, and FFMI were able to predict and explain approximately 2/3 of the variance in ACFT scores in a mixed-sex cohort of cadets. These field expedient measures may serve as an effective screening tool to identify soldiers who are at risk of poor combat fitness and guide exercise and nutrition interventions to enhance soldier ACFT scores and combat effectiveness.