Kinematic and kinetic differences between shod and barefoot running

Abstract

Syrjälä, J. 2016. Kinematic and kinetic differences between shod and barefoot running. Debartment of Biology of Physical Activity, University of Jyväskylä, Master´s Thesis in Biomechanics, 65 p.

Despite the development of footwear technology, the incidence rate of running injuries remains high. The high prevalence of running-related injuries has led to a suggestion that the shoe-development approach is not working efficiently to reduce injuries. The alleged benefits of barefoot running, such as the potential for reduced risk of injury and a more economical approach, has resulted in the scien-tific community and media paying significant attention to barefoot running. Despite multiple differ-ences found in kinematic and kinetic variables, there is no conclusive evidence proving or refuting the proposed advantages of barefoot running. On the other hand, there is no scientific evidence sup-porting the prescription of a shoe with an elevated cushioned heel and pronation control system. Therefore, the purpose of this thesis was twofold. First, to compare the kinematics and kinetics of barefoot and shod running. Second, to critically evaluate the significance of the findings with respect to the proposed advantages of barefoot running.

In total, nine healthy, habitually shod males participated in the study. Subjects were asked to perform running trials on an indoor track at 4m/s in two different conditions: barefoot and shod. A ten-camera system and five mounted force platforms were used to record marker positions and GRF data syn-chronously at 300 and 1500Hz, respectively. The Oxford foot model was used for kinematic model-ling and kinetic variables were calculated using an inverse dynamics approach.

The results showed a few significant differences between the two running conditions, which could have clinical relevance. Barefoot condition showed significantly lower hindfoot-tibia eversion (18.9° ± 6.6°) and forefoot-tibia pronation (25.6° ± 8.0°) range of motion in comparison to shod condition (23.5° ± 5.9°, 30.1° ± 6.3°). These were concomitant with reduction in maximum knee internal rota-tion in barefoot (15.2° ± 14.5°) condition, in comparison to shod (22° ± 14.8°) condition Moreover, the peak knee abductor moment and knee-power absorption were significantly lower in barefoot (1.84 ± 0.72 N·m·kgˉ1, 14.1 ± 4.3 W/kg) than in shod (2.19 ± 0.62 N·m·kgˉ1, 18.1 ± 4.3 W/kg) condition. In previous studies, increased knee internal rotation has been associated to the development and prevalence of iliotibial band syndrome. Furthermore, increased knee abductor moment has been linked to the presence and progression of knee osteoarthritis, and to the development of patellofemo-ral pain syndrome. On the other hand, the results of multi-segment foot model angles in the current study suggest that, when compared to shod condition, the foot rolls over the phalanges more laterally in barefoot condition. An increased lateral roll-off has been shown to be a risk factor for exercise-related lower leg pain. Furthermore, when compared to shod condition, the ankle power absorption was increased in barefoot condition (11.6 ± 2.8 and 8.6 ± 1.6 W/kg in barefoot and shod condition, respectively). This could, in theory, lead to an increased Achilles tendon load in barefoot running. In conclusion, the results of the current study suggest that barefoot running could possibly be beneficial regarding injuries at the knee level, but detrimental regarding injuries at the ankle level.