Foot pressure distributions during walking in African elephants (Loxodonta africana)

Abstract

Elephants, the largest living land mammals, have evolved a specialized foot morphology to help reduce locomotor pressures while supporting their large body mass. Peak pressures that could cause tissue damage are mitigated passively by the anatomy of elephants' feet, yet this mechanism does not seem to work well for some captive animals. This study tests how foot pressures vary among African and Asian elephants from habitats where natural substrates predominate but where foot care protocols differ. Variations in pressure patterns might be related to differences in husbandry, including but not limited to trimming and the substrates that elephants typically stand and move on. Both species' samples exhibited the highest concentration of peak pressures on the lateral digits of their feet (which tend to develop more disease in elephants) and lower pressures around the heel. The trajectories of the foot's centre of pressure were also similar, confirming that when walking at similar speeds, both species load their feet laterally at impact and then shift their weight medially throughout the step until toe-off. Overall, we found evidence of variations in foot pressure patterns that might be attributable to husbandry and other causes, deserving further examination using broader, more comparable samples.

Biomechanical insights into the role of foot pads during locomotion in camelid species

“…In contrast, for camels only 13 of the 21 comparisons among ROIs varied significantly, suggesting less variation in pressure underneath the forefeet in camels, with consistent results for the hindfeet. Similar to our previous studies in elephants and rhinoceroses [14][15][16] , in camels the peak pressures are commonly associated with the toe tips (ROI 3 and 4), while in alpacas, the lateral edges of the foot show the greatest pressures (ROI 2 and 5). Thus, our results highlight that fat pads may also play a mechanical role in in reducing pressures under the foot.…”

“…Data collection. Experiments were conducted at the farms and the experimental protocol is similar to that described by [14][15][16] . Foot pressure data was collected using two custom designed pressure platforms (Zebris Medical GmbH, Biomechanix, Munich).…”

“…Foot pressure data was collected using two custom designed pressure platforms (Zebris Medical GmbH, Biomechanix, Munich). Sampling frequency of each platform was 100 Hz; the outer dimensions of each platform were 0.605 m (width) and 2.122 m (length) with a 48 (width) by 160 (length) array of sensors to total 7680 for each platform 15 . Each individual sensor was 1.27 cm by 1.27 cm.…”

“…regions of peak pressures correlate with skeletal pathologies suggesting that adaptations, such as enlarged fat pads, may be a mechanism to minimize localised regions of high pressure that could cause tissue damage [14][15][16] . However, it remains unknown the extent to which the presence of these fat pads allows large-bodied mammals to deal with both size-and speed-associated increases in musculoskeletal force and foot pressures.…”

Can skeletal surface area predictin vivofoot surface area?

“…The surface area of tetrapod autopodia (feet) reflects several important biomechanical factors, including body mass (McMahon, 1975), habitat (Blackburn et al 1999), speed (Segal et al 2004), and bipedal or quadrupedal locomotory habits (Snyder, 1962). Foot surface area is determined by autopodial morphology and posture (Hildebrand, 1980;Full et al 2002) and, in conjunction with the body mass and locomotory mode of an animal, determines underfoot pressure (Miller et al 2008;Michilsens et al 2009;Panagiotopoulou et al 2012Panagiotopoulou et al , 2016aQian et al 2013).…”