Experimental study reveals reduced propulsive force and altered jump mechanics in soldiers carrying heavy loads, indicating multidimensional neuromuscular fatigue.
Key Points
To evaluate gait, physiological, and neuromuscular adaptations induced by prolonged military load carriage in experienced personnel.
Sixteen male soldiers completed a simulated 12-km military treadmill march while carrying a 30-kg load.
Pre- and post-march assessments recorded ground reaction forces during walking and vertical jumping, alongside heart rate reserve, pelvic accelerometry, and Borg rating of perceived exertion.
Gait propulsive parameters declined post-march, including the second peak of force (1.17 ± 0.05 vs 1.14 ± 0.05 % body weight, p = 0.009, d = 0.88), propulsive force (0.25 ± 0.02 vs 0.24 ± 0.01 % body weight, p = 0.043, d = 0.64), and cadence (112.1 ± 5.81 vs 109.4 ± 5.74 steps/min, p = 0.043, d = 0.64).
Vertical jump power shifted significantly, demonstrated by reduced eccentric braking power (−21.6 ± 4.5 vs −19.6 ± 4.5 W/kg, p = 0.008, d = 0.91) and increased concentric power (49.4 ± 5.8 vs 51.0 ± 6.5 W/kg, p = 0.008, d = 0.92).
Physiological strain increased after the march, marked by elevated heart rate reserve (26.0 ± 6.8 vs 36.9 ± 7.5%, p = 0.006, r = 0.82) and higher perceived exertion (2.7 ± 0.7 vs 5.0 ± 0.7, p < 0.001, r = 0.86).