Physical fitness assessment for lower limb disability: rationale and design to develop a new formula

Introduction: Injuries are a major medical problem in military populations. The physical fitness assessment is a series of tests that measure and monitor physical fitness levels. The existing physical fitness assessment and formula used by the Indonesian Military requires a running test that only applies to healthy soldiers. This study attempted to construct a formula for assessing physical fitness using tests that soldiers may perform with lower limb injury/disability. Method: The design of the study was an internal cross-sectional comparison. This study included 104 healthy, well-trained male normal soldiers (NS) and 50 injured or disabled soldiers (DS) who matched the inclusion criteria. The NS was required to perform a 12-minute running and wheeling test, a ball-throwing test, push-ups, and lunges. The DS was also required to perform the same tests except for the 12-minute running test and lunges. The analysis of the data consisted of four steps: constructing a conceptual framework, describing the characteristics of each group, identifying significant indicators using Partial Least Square-Structural Equation Modeling (PLS-SEM) to develop a physical fitness formula, and determining whether the formula is appropriate for assessing physical fitness in running and wheeling tests. Result: There is no significant difference in the characteristics of NS and DS (p>0.05); thus, the subjects in both groups are comparable. Physical fitness test has several major contributing factors: distance, test method, muscle strength, and age. There is no significant difference in the number of NS in each category between the running and wheeling tests (p>0.05). Conclusion: Physical fitness formula= {1.1 × (0.98 × distance^*) + (0.97 × method value^**)} – (0.093 × age) – (0.17 × muscle strength^***) Note: *) Distance traveled during running or wheeling test (meter). **) The running test method value is entered as 1, and the wheeling test method value is entered as 2. ***) The value of wheeling muscle strength is obtained from the ball-throwing test. In contrast, the value of running muscle strength can be determined by multiplying the result of the ball-throwing test by 2. These findings may be used for assessing the physical fitness of normal soldiers or those with lower limb injury/disability.