Summary: Reasons for performing study: Based upon human data, it is probable that many conditions associated with neck pain in horses may benefit from performing mobilisation exercises as part of the rehabilitation protocol. Objectives: To compare sagittal plane intervertebral angulations in a neutral standing position with the angulations at end range of motion in 3 dynamic mobility exercises performed in cervical flexion. Methods: Sagittal plane motion of the head, neck and back were measured in 8 sound horses standing in a neutral position and in 3 end‐of‐range neck flexion positions: chin‐to‐chest, chin‐between‐carpi, and chin‐between‐fore fetlocks. Skin markers on the head, transverse processes of C1–C6, and dorsal spinous processes of T6, T8, T10, T16, L2, L6, S2 and S4 were tracked and adjacent markers connected to form rigid segments. Intersegmental angles, measured between segments on the ventral surface, in the 4 positions were compared using repeated measures ANOVA with Bonferroni post hoc tests (P<0.05). Results: The largest angular differences involved the cranial and caudal cervical joints with smaller angular differences (<10°) in the mid‐neck. The angle at C1 was significantly more extended for chin‐between‐carpi (98 ± 11°) and chin‐between‐fetlocks (132 ± 11°) than for the neutral position (86 ± 8°) or chin‐to‐chest (92 ± 8°) positions. The intersegmental angle at C6 indicated progressive lowering of the neck from neutral through chin‐to‐chest and chin‐between‐carpi to chin‐between‐fetlocks. The intersegmental angles from T6–L1 were more flexed by 3–7° in the cervical flexions compared with the neutral position with the differences being significant for at least one of the dynamic mobilisations at each vertebral level. Conclusions: The articulations at the extremities of the cervical vertebral column are primarily responsible for sagittal plane position and orientation of the head and neck. Dynamic cervical flexion also flexes the thoracic intervertebral joints. Potential relevance: The results indicate that dynamic mobilisation exercises performed in cervical flexion have applications in mobilising the cervical and thoracic intervertebral joints, which may have some clinical applications in rehabilitation.

Kinematic analysis has been used to understand performance in many sports, but few objective studies of equestrian technique have been published. The objective was to describe movements of the rider's torso and arms relative to movements of the horse's pelvis and shoulder and the position of the bit during trotting. Six experienced female riders rode the same dressage horse at a sitting trot, with rider and horse kinematics collected. The trot is a symmetrical gait, which implies kinematic symmetry between the first and the second halves of the gait. Three trials of a half stride, from left forelimb lift-off to right forelimb lift-off, were analysed for each subject. In all riders, trunk angle was maximal (backward tilt) in early stance, at which time the rider's hips were closest to and the rider's shoulders were furthest from the bit. Trunk angle was minimal (forward tilt) at the end of stance when the shoulders were closest to and the hips were furthest from the bit. Range of motion of the rider's hips and shoulders varied greatly between subjects. Movements of the rider's shoulder joint and elbow joint were synchronized with the trunk oscillations, so the distance from the rider's wrist to the horse's bit changed by only 15 ± 3 mm during the stride. It is concluded that the six experienced riders were able to accommodate the motion of the horse's body while maintaining a consistent contact with the bit by minimizing changes in the distance from the wrist to the bit.

Summary: The objective was to measure 3D rotations of the distal (DIP) and proximal (PIP) interphalangeal joints at walk and trot. 3D trajectories of markers fixed to the proximal phalanx, middle phalanx and the hoof wall of the right forelimb of four sound horses were recorded at 120 Hz. Joint kinematics were calculated in terms of anatomically-based joint coordinate systems between the bone segments. Ranges of motion were similar at walk and trot. Values for the DIP joint were: flexion/extension: 46 ± 3° at walk, 47 ± 4° at trot; internal/ external rotation: 5 ± 1° at walk, 6 ± 3° at trot; and adduction/abduction: 5 ± 2° at walk, 5 ± 3° at trot. Within each gait, kinematic profiles at the DIP joint were similar between horses with the exception of adduction/abduction during breakover, which may vary depending on the direction of hoof rotation over the toe. Knowledge of the types and amounts of motion at the DIP joint will be useful in understanding the aetiology and treatment of injuries to the soft tissues, which are being recognized more frequently through the use of sensitive imaging techniques. Ranges of motion for the PIP joint were: flexion/extension: 13 ± 4° at walk, 14 ± 4° at trot; adduction/abduction: 3 ± 1° at walk, 3 ± 1° at trot; and internal/external rotation: 3 ± 1° at walk, 4 ± 1° at trot. The PIP joint made a significant contribution to flexion/extension of the digit. During surgical arthrodesis, the angle of fusion may be important since loss of PIP joint extension in late stance is likely to be accommodated by increased extension of the DIP joint.