Tactical Strength and Conditioning
William D. Hale, CSCS, EIM
Assistant Professor of Exercise and Sport Sciences
The University of Tulsa
Tulsa, Oklahoma, United States
Roger O. Kollock, Jr., PhD, AT, CSCS
Associate Professor of Exercise and Sports Science
The University of Tulsa
Tulsa, Oklahoma, United States
Firefighters are routinely assigned the tasks of carrying external loads consisting of equipment and gear ranging from 20-35kg. The additional external load is standard but not personalized resulting in firefighters carrying inconsistent amounts of dead mass (DM). The ability to manage a load may be dependent on fat mass. A novel way to categorize load assignment is based on firefighter body composition and the mass of the external load. The load carriage index (LCI) = (lean body mass)/(fat mass + external load) is the proportion of lean body mass to compared to their DM. Firefighter ability to manage load may be dependent on absolute and relative strength factors due to additional muscle mass.
Purpose: This study was conducted to determine possible associations between the load carriage index (LCI) with whole-body absolute and relative strength in career male firefighters.
Methods: Male career firefighters (n=18, 35+/-8 yrs) completed a bioelectrical impedance body composition assessment (20.01±8.13) and a whole-body isometric strength test. The whole-body strength test consisted of an isometric midthigh pull (IMTP)l using a load cell. The IMTP required firefighters to complete 3 trials of a 5-sec isometric contraction using a custom strength testing device with an integrated load cell. The peak IMTP value was used to calculate relative strength(1.81kg±.392) (peak IMTP/body weight). The peak IMPT value was used to represent absolute strength (160.30kg±32.65). Bivariate correlations were used to determine the association of the LCI with weight pulled in kilograms. Alpha level was set a priori at .05.
Results: Both whole-body absolute strength (r = .500; p = .041) and relative strength (.584; p = .014) demonstrated a positive significant correlation with the LCI.
Conclusion: Career firefighters who possess higher amounts of whole-body absolute and relative strength have higher values on the LCI. Their ability to manage a load is not only dependent on their DM, but also higher amounts of lean mass in the form of skeletal muscle. Practical Application: Load carriage management can be improved by increases in muscle force production and decrease in fat mass.
Acknowledgements:
Acknowledgements: The Oklahoma Center for the Advancement of Science and Technology (OCAST) grant number HR18-054. The results of the present study do not constitute endorsement by the Oklahoma Center for the Advancement of Science and Technology.