With the start of summer, it is not a surprise we are seeing more hiking related injuries – whether that’s just at the foot and ankle or even further up to the knee or hip. Three recent studies offer unique insights into how hiking changes foot mechanics, how footwear influences movement, and the effect of backpack weight.
Study 1: A 20-km Hike Changes Foot Shape and Walking Mechanics (An et al., 2025)
This study investigated how a 20-km hike affects foot morphology and gait in 79 healthy adults carrying approximately 33 backpacks. Researchers measured participants’ feet using a 3D foot scanner and analyzed gait and plantar forces immediately before and after the hike.
Key findings
While the foot typically swells and lengthens following running, with hiking, the researchers found:
- A significant decrease in foot length following the hike
- Reduced plantar force beneath the toes, central forefoot, and midfoot
- Results likely reflected muscular fatigue and altered walking mechanics
The authors proposed that prolonged hiking causes the toes to contract and that fatigued intrinsic foot muscles reduce the ability to generate normal push-off forces. As a result, hikers may begin relying on compensatory movement strategies. As foot muscles tire, athletes may lose efficiency during push-off, increasing stress on the ankle, knee, and hip. This reinforces the importance of foot intrinsic strengthening and calf endurance for hikers and endurance athletes.
Study 2: Hiking Boot Design Changes How Forces Are Distributed (Kersting et al., 2021)
Another study examined whether tall hiking boots improve stability. Researchers compared one low-cut hiking shoe with three tall hiking boots
Key findings
Compared with low-cut shoes, tall hiking boots:
- Reduced ankle plantarflexion and dorsiflexion range of motion
- Decreased the amount of muscular work at the ankle
- Increased eccentric work performed at the knee
Ankle support helps to redistribute forces. While a supportive hiking boot may improve stability individuals with ankle instability, the knee absorbs more of the workload and should be assessed/addressed in PT.
Study 3: Backpack Weight Significantly Increases Plantar Pressure (Moya-Cuenca et al., 2026)
A third study investigated how backpack weight affects plantar loading in long-distance hikers. Participants completed plantar pressure testing while carrying: no backpack, their usual hiking pack, a pack equal to 10% of body weight, and a pack equal to 20% of body weight.
Key findings
Researchers found:
- Forefoot pressure increased by over 5% with a 10% body-weight load and nearly 9% with a 20% load
- Rearfoot pressure increased approximately 10% with heavier loads
- Total plantar pressure progressively increased as backpack weight increased
Once backpack loads exceeded 10% of body weight, pressure changes became statistically significant. Higher plantar pressures may contribute to overuse injuries such as plantar fasciitis, metatarsalgia, stress reactions, and fatigue-related gait compensations.
What This Means for our Hikers and Endurance Athletes
Together, these studies reinforce that hiking places unique demands on the foot and ankle. Fatigue changes how the foot functions, boot design changes how forces move through the lower extremity and backpack weight increases the mechanical load experienced by the foot with every step. These are just 3 things to consider with patients who enjoy long distance hiking or even ultra endurance athletes.
Article References:
An, J., Ryue, J., Lee, J., & Lee, K.-K. (2025). Changes of foot morphology and gait pattern after loaded 20-km hiking. Footwear Science, 17(sup1), S227–S228. https://doi.org/10.1080/19424280.2025.2492288
Kersting, U. G., Støttrup, N., & Larsen, F. G. (2021). The influence of shaft stiffness on joint kinematics and kinetics during hiking. Journal of Biomechanics, 126, 110643.https://doi.org/10.1016/j.jbiomech.2021.110643
Moya-Cuenca, C., Zúnica-García, S., Gracia-Sánchez, A., García-Cremades, S., Oltra-Romero, A.M., & Chicharro-Luna, E. (2026). Plantar pressure responses to backpack load in long-distance hikers: A cross-sectional observational study. Journal of Functional Morphology and Kinesiology, 11(1), 36. https://doi.org/10.3390/jfmk11010036