B-11 Thematic Poster - Landing Biomechanics Wednesday, May 31, 2017, 1:00 PM - 3:00 PM Room: 101
Multi-segment foot models have allowed the foot to be studied in greater detail, in particular separating the functions of the ankle and midtarsal joints. While these models have been used in walking and running, they have been limited in application to other sports movements, such as jumping and landing.
PURPOSE: To investigate the role of the midtarsal and ankle joints in energy absorption during drop landings using a multi-segment foot modeling approach, and to compare these results with those obtained from a single segment model.
METHODS: Twelve volunteer female collegiate athletes [age: 20.5±1.4 years, height: 162.1±5.4 cm, weight: 58.2±6.1 kg] performed one legged barefoot drop landings from a height of 40 cm. Hanging from wooden rings, each subject dropped onto two adjacent force platforms, so that the hindfoot and forefoot contacted separate plates. Sufficient trials were performed until 3 accurate landings were achieved. 28 reflective markers, attached to the subjects’ dominant leg, were used to create a custom kinetic multi-segment foot model. Ankle and midtarsal joint angles, powers, and total work were calculated from initial contact through the lowest point of the subject’s center of mass, representing the energy absorption phase of the landing.
RESULTS: The midtarsal joint was plantarflexed prior to contact and moved through nearly as great a range of motion (90%) as the ankle (24.6 ± 7.3° ankle vs. 21.9 ± 7.5° midtarsal), while performing two-thirds the amount of work done by the ankle (0.63 ± 0.21 J/kg at the ankle vs. 0.42 ± 0.17 J/kg at the midtarsals). The single segment foot overestimated both range of motion (40.4 ± 8.8°) and work done (1.05 ± 0.28 J/kg) by 40%.
CONCLUSION: The midtarsals can play a substantial role in impact energy absorption, which may have implications in injury prevention strategies. Future studies should attempt to separate active (i.e. muscles) and passive (e.g. ligaments, windlass mechanism, etc.) contributions to midtarsal function.