P2.190  Thursday, Jan. 5  Gearing of galloping in the cheetah and racing greyhound HUDSON, PE*; CORR, SA; WILSON, AM; Royal Veterinary College, London; Royal Veterinary College, London; Royal Veterinary College, London phudson@rvc.ac.uk

Within an animal’s limbs there are several levels of gearing; from the myosin isoforms and the internal architecture of a muscle to the overall limb posture. Previous work on cheetahs and greyhound found cheetahs to have significantly longer muscle moment arms than the greyhounds. Following on from this we investigated whether the differences observed in their musculoskeletal gearing have an impact on the functional capabilities of their limb.

Simultaneous force plate (3500 Hz) and high speed video data (1000 Hz) were collected for two captive South African cheetahs and six ex-racing greyhounds, whilst they performed a steady state rotary gallop, and their limb posture, joint moments and Effective Mechanical Advantage (EMA) were investigated.

Posture is often thought of in terms of body weight support, i.e. larger, more massive, animals use a straighter limb posture (larger EMA). In this study it was hypothesised that the cheetah, a faster animal would use a straighter limb posture than the greyhound and that limbs would be straighter at higher speed to withstand the larger peak forces the limbs experience at higher speeds. No correlations between joint angles and speed were found with the exception of the tarsus and metatarso-phalangeal joints which became more flexed with increasing speed. The cheetahs also used a more crouched posture than the greyhound throughout stance. This may reflect greater leg shortening/compression at higher forces or an adaptation for manoeuvring.