By Rob Shaul
BLUF
This 2025 study (Scientific Reports, Han et al.) examined how footwear influences tibial loading when carrying weight during walking — specifically comparing barefoot, athletic shoes, and military boots at 0, 15, and 30 kg carried loads.
While tibial loading increased with added weight across all footwear, military boots blunted that increase above 15 kg. In contrast, trainers showed a linear increase in tibial stress from 0 → 15 → 30 kg.
The results suggest that boot stiffness and restricted ankle motion may redistribute forces, limiting additional tibial strain under heavy loads … and for rucking or ruck training, boots are better to reduce impact and prevent injury.
Overview
A 2025 Scientific Reports study by Han and colleagues investigated how footwear modifies tibial loading during loaded walking. The researchers compared barefoot walking, athletic shoes, and military boots while participants carried loads of 0, 15, and 30 kilograms at a controlled speed of 1.67 meters per second. Using motion capture and force platforms, they modeled tibial bending and cumulative loading to see how boots and shoes affect lower-limb stress during rucking.
Subjects: 10 military-trained male participants (mean age = 24 ± 3 yrs).
Conditions:
• Three loads: 0 kg, 15 kg, 30 kg (using a backpack with barbell plates).
• 3 footwear types: barefoot, trainers, military boots.
• Walking speed fixed at 1.67 m/s.
Measurements:
• Kinematics (120 Hz) and ground reaction forces (1200 Hz).
• Musculoskeletal modeling estimated tibial bending moments and cumulative tibial impulse per km.
Key Findings
Tibial Loading and Footwear – Tibial stress increased as load increased across all conditions, but footwear made a measurable difference. In both barefoot and trainer conditions, tibial strain rose linearly with added weight. However, military boots showed a different pattern—stress increased from 0 to 15 kilograms but plateaued between 15 and 30 kilograms. The study’s authors concluded that the boots’ stiffer structure and restricted ankle motion likely redistributed or absorbed some of the additional forces, limiting further tibial loading at heavy weights.
Energy Absorption and Ankle Mechanics – Participants wearing boots demonstrated higher negative (absorptive) ankle power and lower positive (propulsive) power compared to the other conditions. In effect, the boots absorbed more energy at heel strike but returned less at push-off. This indicates a damping effect—energy that might otherwise transfer up the tibia was absorbed or dissipated by the stiff boot sole and shaft.
Stride mechanics also changed. Subjects wearing boots walked with slightly longer contact times and lower stride frequency, suggesting a slower, more deliberate gait pattern emphasizing stability over efficiency.
Interpretation – The results suggest that military boots blunt tibial stress beyond moderate loads—likely by restricting ankle mobility and increasing energy absorption. While this may protect the tibia from excessive bending and help reduce stress fracture risk under heavy loads, it comes with trade-offs. Less efficient energy return increases metabolic demand and may contribute to fatigue over prolonged distances. The mechanical load doesn’t disappear—it is simply redistributed, potentially moving stress upward to the knee or hip.
Takeaways
Military boots appear to mitigate further tibial stress at heavy loads, suggesting they provide some protective benefit for the shin under load carriage. However, this protection likely increases energy cost and may shift joint stress proximally. From a training perspective, alternating between heavy ruck sessions in operational boots and lighter load work in more flexible footwear may preserve ankle mobility and balance lower-limb conditioning.
At MTI, our lab rats often ruck in trail running shoes … and this study suggests that we should shift to military boots to reduce lower limb impact.
Source:
Ian, S., Park, J., Lee, J., Ellison, M., Farris, D., & Rice, H. (2025). Footwear has a modifying effect on tibial loading during military weight carriage. Scientific Reports, 15, 26531. https://doi.org/10.1038/s41598-025-11202-8