Camera speeds for optoelectronic assessment of stride-timing characteristics in horses at the trot.

Quantitated locomotion analysis is increasingly being used during assessment and treatment of gait disorders in human beings. Locomotion analysis is also thought to have potential for enhancing the assessment of lameness in horses. Availability of high-speed video recording systems has simplified the process of quantitated locomotion analysis; however, the high cost of such systems has limited their use for routine clinical assessment in horses. The temporal resolution of 500- to 1,000-images/s (Hz) recording systems is beyond what has been considered necessary for precise quantitation of short-duration events in horses at the trot; however, it is uncertain whether the temporal resolution of more economical 60-Hz recording systems is adequate. To determine whether a recording rate of 60 Hz is satisfactory for assessment of stride-timing values in horses at the trot, the stride-timing values calculated from 60-Hz recordings were compared with those calculated from 1,000-Hz recordings that had been simultaneously made for 5 horses trotting on a horizontal treadmill at a speed of 3.0 m/s. The left forefoot of each horse was fitted with an instrumented horseshoe that illuminated and quenched light-emitting diodes (LED) in view of both cameras precisely at toe contact, heel contact, heel lift, and toe lift. The exact pattern and timing of foot placement and lift was referenced by the illumination pattern of the LED. Recordings of 10 consecutive strides were reviewed, image by image for each horse, and the elapsed time at each important stride event was tabulated.(ABSTRACT TRUNCATED AT 250 WORDS)