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 or disability. 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. 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). The analysis has a strong result with R-square = 0,976 (means 97,6% appropriate compare with Cooper test). Conclusion: Physical fitness Ernandini 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 or disability.