Sex differences in muscle quality of firefighter recruits: a new exploratory approach to evaluation

Abstract Background: Firefighting is a hazardous occupation that requires optimal fitness levels as it put tremendous strain on the cardiovascular system. Poor body composition could contribute to the increased risk of cardiac events and reduced functional capacity. Objective: The aims of this study were (1) to analyze the body composition of Italian firefighters, comparing males and females; and (2) to investigate if fitness values could be predictive of Muscle Quality (MQ) in male and female firefighters. Methods: Anthropometric (weight, height, body mass index, and BIA) and fitness (handgrip, upper and lower body strength, and VO2max) parameters of 23 firefighters’ recruits (female = 11; male = 12; age: 36.70 ± 4.68 years; weight: 69.14 ± 12.19 kg; height: 169.30 ± 6.93 cm; BMI: 23.97 ± 2.77 kg/m2) were analyzed. An independent t test was used to evaluate sex differences, and multiple linear regression with backward stepwise elimination was considered to evaluate the muscle quality index (MQI) dependence on anthropometric and fitness variables. Results: Statistical differences (p < 0.05) between sex groups emerged in all anthropometric and fitness parameters and MQI. Only three variables were found significant (F(3, 19) = 4012.20, p < 0.001; R2 adjusted = 0.998). MQI values were strongly positively associated with the Handgrip test (t = 45.55; p < 0.001), and negatively associated with the Bench press test (t = −2.14; p = 0.045) and female status (t = −1.88; p = 0.075). Conclusions: Our results confirm that sex and fitness parameters could be predictive of MQ values in recruits’ firefighters, and the easy evaluation of this parameter could provide helpful information for developing specific interventions for healthy lifestyle promotion in firefighters.