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The muscles investigated were significantly affected by hip OA. This finding suggests that there is a more distinct resting phase of the muscles during swing and a higher activity during early stance.

SummaryReason for performing study: The rectus abdominis (RA) and oblique external abdominal (OEA) muscles are both part of the construction of the equine trunk and thought to be essential for the function of the spine during locomotion. Although RA activity at trot has previously been investigated, the relationship between OEA and RA at walk and trot has not yet been described. Objectives: To document abdominal muscle activities during walk and trot, and test the hypothesis that muscle activity at walk would be smaller than at trot. Materials and methods: Six horses (8-20 years old, 450-700 kg) were used for surface electromyography (EMG) measurements, with EMG electrodes placed caudal to the sternum (RA) and at the level of the 16th rib (OEA). On all hooves, the withers and the sacrum reflective markers were placed to determine motion cycles. Normal distribution of data was tested using a Kolmogorov-Smirnov test and Student's t test was used to compare left-right and walk-trot differences (P<0.05). Results: Minimum, maximum and mean EMG values recorded at walk were significantly higher at trot than at walk in all horses for OEA and in 5/6 horses for RA. At walk, EMG activity ranged from 8-44 mV (RA) and 7-54 mV (OEA). At trot, EMG activity ranged from 18-150 mV (RA) and 27-239 mV (OEA). There were statistically significant differences between maximum activities of left and right OEA and RA muscles at walk in all horses, and in 4/6 horses at trot. Conclusions: Muscle activities of OEA and RA are smaller at walk than at trot. At walk, the OEA/RA ratio is lower than at trot. There are more significant correlations between muscle activities of both RA and OEA and limb movements at walk than at the trot.

SummaryReason for performing study: The motion of the atlantooccipital, cervical vertebral and cervicothoracic joints play an important role in equestrian sports and they are also common sites for lesions limiting performance in horses. Objectives: To calculate inverse kinematics based on cervical vertebral motion and to develop a model close to the measured neck movements. Materials and methods: Measurements were recorded in 6 horses without neck pain. Reflective markers were placed on both cristae facialis, both sides of cervical vertebra 1, 3 and 6 on the withers and hooves. The neck model was reconstructed from CT scans of the osseus structures and was developed in SIMM (Software for Interactive Musculoskeletal Modelling). Inverse kinematics calculation was done in OpenSim. Three degrees of freedom: Flexion-extension (FE), axial rotation (AR) and lateral bending (LB) were considered. The simulated motion was generated from the recorded motion of the skin markers. The differences in angular range of motion (ROM) of the joints were analysed using paired sample t tests. Results: From the model, the smallest FE ROM was in the C5-C6 joint (2°Ϯ 1°) and the largest was in the C3-C4 joint (11°Ϯ 5°). The smallest AR ROM was in the C5-C6 joint (2°Ϯ 1°) and largest AR ROM was in the atlantoaxial joint (7°Ϯ 2°). The smallest LB ROM was in the C5-C6 joint (2°Ϯ 1°) and the largest LB ROM was in the cervicothoracic joint (18°Ϯ 5°). There were significant differences between the ROM of joints in 51 of 168 comparisons (P<0.05). Conclusions:The result of the motion of each joint gives an insight into the biomechanics of the equine neck. The small FE ROM at C5-C6 illustrates the pathogenetical relevance of the model for the development of osteoarthritis. The calculated data also provides a source for inverse dynamics.evj_265 516..522

Ataxia is best documented and examined at the walk. At trot pendulum effect may make coordination easier for horses. The results of this study serve as basic data for evaluating questionably ataxic horses.

This study demonstrated that a well chosen saddle pad can reduce the load on the horse's back and therefore improve the suitability of a fitting saddle.

SummaryReasons for performing study: Skeletal muscle activity can be concentric or eccentric, anisometric or isometric and correlation of the equine splenius muscle activity with the movement of its effector joints at walk and trot has not yet been fully characterised. Objective: Investigating activity of the splenius muscle together with kinematics of head and cranial neck at walk and trot.

No abstract