Correlations between Physical Fitness Tests and Performance of Military Tasks: A Systematic Review and Meta-Analyses

Abstract

To help evaluate the Army Physical Fitness Test (APFT) and ensure a future test is associated with Soldiers' performance of common physical job requirements, the USAPHC applied a Systematic Review (SR) methodology to identify and synthesize published correlations between military task performance and physical fitness tests. Methods: A preliminary step to our SR was to identify key military-relevant tasks and physical fitness components of interest. Starting with the Army's Warrior Tasks and Battle Drills (WTBDs), twelve task categories were identified, including some tasks performed by both military and civilian occupations (e.g., firefighters, police, and athletes). Physical fitness tests were sorted into four physical fitness groups: cardiorespiratory endurance (e.g., aerobic fitness), muscle strength, muscle endurance, and flexibility. Tests of muscular strength and muscular endurance were further subcategorized into Upper and Lower Body, Core, or Whole Body regions. Physical tests included the APFT events (2-mile run, sit ups, push-ups) as well as other equipment and non-equipment physical fitness tests (e.g., jump tests, squats, sprints, pull-ups, grip tests, arm lifts, curls, and various extension machine tests). To synthesize the data, a series of meta-analyses provided pooled correlation coefficients for the twelve tasks and eleven physical fitness test groups. Results: Flexibility tests were the least frequently identified, while upper body strength tests were most frequently identified in studies that met our inclusion criteria. Correlations with aerobic tests were fairly well studied, with a few notable gaps (e.g., the Loaded March task). Pooled r coefficients for specific physical tests (e.g., run tests, push-ups, sit-ups, grip tests, and vertical and broad jump tests) were also calculated. Of the physical fitness component groups evaluated, aerobic capacity is most strongly correlated across the greatest number of military tasks (highest r = 0.80, average r for all tasks = 0.53, average r for the top 5 tasks = 0.68, r value range = 0.30-0.80). Of next importance, muscular strength and endurance both have strong correlations with lifting, lowering, stretcher carry and crawl (average for top 5 tasks= r >0.50). Lower body strength and endurance tests (average top 5 task r = 0.63 and r = 0.58) are of similar strength to correlations for top correlations with upper body endurance (average top 5 task r = 0.57). Core endurance, and sit-ups specifically, are weakly correlated with most tasks (average r for all tasks= 0.33; for top 5 tasks r = 0.38). Conclusions: A test of aerobic capacity is fundamental for assessing Soldiers' basic physical capacity to conduct critical tasks, while sit-ups do not appear to be an important test. Muscle strength and endurance are also critical physical components. Since the current APFT does not include a measure of muscle strength or power, consideration should be given to fill this gap in future testing requirements.

Perspectives on Aerobic and Strength Influences on Military Physical Readiness

“…The incremental dynamic lift was originally developed by the Air Force. Teves et al reported that the incremental dynamic lift was superior to handgrip strength, isometric 38 cm upright pull strength, body composition, and submaximal prediction of oxygen uptake when predicting job related criterion performance tasks (job requirements involving pulling, pushing, lifting, carrying, and applying torque) (27). Although it was recommended that the Army adopt this test to assess muscle strength before job assignment, the Army did not implement it as a strength test.…”

“…Examples include a 20-to 30-kg sand and box lift (Canada, Australia, United Kingdom, Germany, and U.S. Marine Corps) and casualty (50-80 kg) drag (15-30 m) (Canada, United Kingdom, and Germany) (27).…”

“…A recent systematic review of literature on the correlation of the components of physical fitness with performance of 11 military tasks (e.g., lifting, lifting and lowering, casualty drags, stretcher carrying, road marching with loads, climbing, crawling, and digging) found that aerobic fitness was more highly correlated with more such tasks than muscle strength or muscle endurance (27). Strong and consistent associations of a component of physical fitness with musculoskeletal injury risk suggests that tasks requiring that component of fitness are either common or biomechanically stressful or both.…”

The Biomechanics and Applications of Strongman Exercises: a Systematic Review

“…The current heavy sled pull research may be used as a basis for further research into the biomechanical demands of performing other variations of pulling type exercises such as the backward drag. The backward drag technique is used in firefighting and military physical fitness assessments and service, where service people may be required to drag victims out of danger [50, 51]. Further investigation into the biomechanical demands of a vehicle pull may be of benefit to military operations, as soldiers may be faced with instances where they are required to pull/push heavy equipment over short distances [51].…”

The Added Value of Musculoskeletal Simulation for the Study of Physical Performance in Military Tasks

“…Furthermore, other activities and different terrains should be investigated in future studies to get better insights of military performance during a broad range of tasks and situations [ 64 ]. The method presented in this study can be directly used for several walking and running activities.…”