Equine Biomechanics and Gait Analysis
This domain tests how forces, timing, and limb coordination produce gait, and how to measure asymmetry without overreading a single stride. Expect questions on stride phases, gait sequences, ground reaction forces, and collection versus extension.
Core rules
- A stride has stance and swing; duty factor is stance time divided by stride time. Walk is a four-beat lateral sequence; trot is two-beat diagonal; canter is three-beat with a suspension phase; gallop is four-beat.
- Kinetics includes ground reaction force and center of pressure; kinematics includes joint angles, stride length, and temporal variables. Speed changes stride length and frequency, so compare horses at matched speed.
- Breakover is the phase from heel-off to toe-off; a long toe or underrun heel increases the lever arm and stress on the deep flexor apparatus.
- Collection shortens the stride, elevates the neck and poll, and increases hindlimb engagement; extension lengthens the stride and lowers the neck.
- Forelimb lameness at trot typically produces a head nod: the head rises when the affected limb bears weight and drops when the sound limb bears weight.
Worked example
A horse is sound on the straight but 2/5 lame on a circle to the right. Reasoning: circling increases load on the inside limbs and can expose suspensory or joint pain. If the head rises when the right forelimb is weight-bearing, the right forelimb is likely affected. Confirm with flexion tests and diagnostic blocks, not with a single video frame.
Traps
Calling canter four-beat; comparing stride length between horses at different speeds; mistaking a head nod for a training issue; and assuming all asymmetry is pain rather than strength or conformation.