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Jane (2012) The influence of barefoot and barefoot inspired footwear on the kinetics and kinematics of running in comparison to conventional running shoes. Footwear Science, 5 (1).

Summary 22Background: Locomotion adaptation mechanisms have been observed in horses, but little 23 information is available in relation to banked and non-banked curve locomotion, which might 24 be important for correct training. 25Aim: To determine if adaptation mechanisms in horses existed when moving on a banked 26 compared to a flat curve and whether adaptation was similar in different gaits. Introduction 45The kinematics of walk, trot and canter gaits have been studied over ground and using 46 treadmills in two dimensions (Barrey et al., 1993; van Weeren et al., 1993; Buchner et al., 47 1994; Clayton, 1994; Back et al., 1996; Galisteo et al., 1998; Galisteo et al., 2001; Clayton et 48 al., 2002) and three dimensions (Chateau et al., 2004; Chateau et al., 2006; Hobbs et al., 49 2006; Clayton et al., 2007a; 2007b; Gomez Alvarez et al., 2009). From these studies 50 adaptation mechanisms have been observed during treadmill locomotion (Barrey et al., 1993; 51 Buchner et al., 1994; Gomez Alvarez et al., 2009) and other studies have reported adaptations 52 due to shoeing regimens and hoof conformation, which include Clayton et al. (1990), 53 Roepstorff et al. (1999) and van Heel et al. (2006). To date, few studies have investigated 54 adaptations in kinematics during locomotion on a curve. powered by torque about the hip joint and by back extension (Usherwood and Wilson, 2005). 61In contrast, the muscles that power sprinting in humans are loaded by weight induced 62 compression forces along the leg and a greater proportion of the maximum muscular effort 63 must be directed medio-laterally in order to develop centripetal acceleration (Usherwood and 64 Wilson, 2005). Chang and Kram (2007) found the inside leg to be particularly ineffective at 65 generating push off forces for propulsion in humans and proposed that this is due to a need to 66 optimise the alignment of the resultant GRF vector with the long axis of the leg. They the distal segments that were internally rotated at the end of the weight bearing phase. From 92 these studies it is clear that adaptations to curve motion are also found in horses, but 93 constraints placed on the limbs at faster speeds are unknown. 94Fredricson and Drevemo (1971) recognised that the characteristics of the surface, banking, 95 curve and gradient as well as surface variation will affect the trotting action. In this respect 96 they suggested that at high speed good horses can compensate for many of these factors, but 97 to the expense of wear and tear on their limbs. The risk of injury to the distal joints when 98 negotiating curves may increase further for horses performing at faster gaits and over longer 99 time periods, as Johnston et al. (1999) found stride length, stance time and joint excursion 100 during stance to increase with fatigue. Hill (2003) remarked that most catastrophic injuries in 101 racing will occur in turns and in the stretch run to the finish. In a study of 58 horses suffering 102 serious accidents during racing, Ueda et al. (...

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Background. Although the trot is described as a diagonal gait, contacts of the diagonal pairs of hooves are not usually perfectly synchronized. Although subtle, the timing dissociation between contacts of each diagonal pair could have consequences on gait dynamics and provide insight into the functional strategies employed. This study explores the mechanical effects of different diagonal dissociation patterns when speed was matched between individuals and how these effects link to moderate, natural changes in trotting speed. We anticipate that hind-first diagonal dissociation at contact increases with speed, diagonal dissociation at contact can reduce collision-based energy losses and predominant dissociation patterns will be evident within individuals.Methods. The study was performed in two parts: in the first 17 horses performed speed-matched trotting trials and in the second, five horses each performed 10 trotting trials that represented a range of individually preferred speeds. Standard motion capture provided kinematic data that were synchronized with ground reaction force (GRF) data from a series of force plates. The data were analyzed further to determine temporal, speed, GRF, postural, mass distribution, moment, and collision dynamics parameters.Results. Fore-first, synchronous, and hind-first dissociations were found in horses trotting at (3.3 m/s ± 10%). In these speed-matched trials, mean centre of pressure (COP) cranio-caudal location differed significantly between the three dissociation categories. The COP moved systematically and significantly (P = .001) from being more caudally located in hind-first dissociation (mean location = 0.41 ± 0.04) through synchronous (0.36 ± 0.02) to a more cranial location in fore-first dissociation (0.32 ± 0.02). Dissociation patterns were found to influence function, posture, and balance parameters. Over a moderate speed range, peak vertical forelimb GRF had a strong relationship with dissociation time (R = .594; P < .01) and speed (R = .789; P < .01), but peak vertical hindlimb GRF did not have a significant relationship with dissociation time (R = .085; P > 0.05) or speed (R = .223; P = .023).Discussion. The results indicate that at moderate speeds individual horses use dissociation patterns that allow them to maintain trunk pitch stability through management of the cranio-caudal location of the COP. During the hoof-ground collisions, reduced mechanical energy losses were found in hind-first dissociations compared to fully synchronous contacts. As speed increased, only forelimb vertical peak force increased so dissociations tended towards hind-first, which shifted the net COP caudally and balanced trunk pitching moments.