The Study of Human-Animal Interactions The CAIRC Scholarship Program Summary of the Past Researches
Summary of the Past Scholarship Research
From "Letter from CAIRC" July 2000
Research Theme: "Physiological Research on the Relationship between Handicapped People and Horses during Horseback Riding"

By Masako Tsuzuki, Hiromi Keino, Kunihiko Ito and Katsumi Mita
This research was presented by Ms. Masako Tsuzuki, who works as clinical testing technician at a medical and welfare research facility in Aichi Prefecture. The Institute for Developmental Research Aichi Human Service Center is a comprehensive medical and welfare research facility supporting physically and mentally handicapped people in such areas as medical treatment, education, vocational training and vocational aid. It also provides consultation and advice to home-bound disabled people and their families and conducts research into the causes of handicaps and how best to treat or compensate for them. Horseback riding an animal-assisted rehabilitative activity that is said to be effective from the perspective of its medical, educational and social effects as well as its role as a sporting activity. An increasing number of facilities have adopted this activity into their programs in the past few years. However, there is little or no data to gauge its effectiveness, only descriptive information.

Ms. Tsuzuki and her team have so far created several methods of evaluating the effectiveness of horseback riding for handicapped people, and have published some of them. A simple method to evaluate the mental effects has also been presented as a HEIM score. This is a method based on the Childhood Autism Rating Scale, a standard by which autism is evaluated. It sets 10 selected items such as interpersonal relations, imitative action and sudden movement, and evaluates each item on a scale of five degrees of intensity. As a more objective method, the team also created a way of evaluating the manifestation of emotions with respect to the way smiles appear. This method evaluates the emergence of a smile in five stages. The subject's face is tested by videotaping it before, during and after the exercise. The test subject then judges the image of his or her own facial expressions in still images randomly selected from the video capture board. The team also created the HEIP score to judge physical effects of the activity. In this testing method, manifestations of cerebral palsy in the subject's upper body, hands and feet are divided into 8 levels, and then evaluated by breaking each level down into four sub-levels. The team has proven that horseback riding therapy has a strong effect on people with cerebral palsy.

This presentation is part of a series of efforts by the team toward an interim report aimed at establishing the best method by which to evaluate the effectiveness of horseback riding for the handicapped. It has been found that when handicapped people ride horses, their bodies becomes less tense and can more readily relax. This is especially true of subjects with cerebral palsy. Research team members thought that they would be able to measure this effect more precisely by demonstrating the physiological signals that indicate it. They therefore attached accelerometers and electromyography sensors to the humans and horses involved as they conducted their experiments in horseback riding.

The researchers measured the acceleration velocity simultaneously of both the humans and horses so that they could analyze recovery reactions that occur when people lose balance. The measurement used a small three-dimentional — back-front, left-right and up-down — accelerometer. For the electromyogram data, they carried out differential amplification using surface electrodes with a 15-milimeter diameter. Signals were collected through telemeter devices via radio transmission. For horse steps, they set a 6-meter run-up interval before the 21-meter measurement section of the course. The horse's walking velocity was measured at two different speeds, one at footpace (about 4 kilometers per hour) and the other at quicksteps (about 13 kilometers per hour). Six riders were selected — three able-bodied adults with horseback riding experience and another three subjects without.

According to the test results, the horse's acceleration velocity at footpace showed complex changes in all three dimensions, while that of the humans showed relatively simple waveforms. In addition, subjects with riding experience clearly showed narrower maximum changes in the up-down dimension. As a causative factor behind decreased acceleration velocity for humans, it is possible to assume that they absorbed the horse's movement with their bodies in order to maintain the head at a specific position. On the other hand, the acceleration velocity during quicksteps was five times as great as that at footpace. From these data, Ms. Tsuzuki's team draws the assumption that as they accumulate horseback riding experience, people learn to stabilize their quickstep horseback riding through backward motions that conform with the horse's up-and-down motion. In the future, Ms. Tsuzuki's team aims to measure data for the handicapped and analyze and compare it with that of healthy people, look for specific tendencies, and contrast data obtained before and after horseback riding. Ms. Tsuzuki said: "I would like to aim at creating an index for the effectiveness of horseback riding for the handicapped."

The team said the electromyogram failed to detect accurate numeric value because of noise from the friction of clothing and the thighs touching the horse's trunk. They are working on resolving these problems, and the team said they would like to conduct this experiment again.

For the experiment, they selected Kiso horses known for being placid, docile and patient. These horses were once of primary importance in Japanese agriculture and transportation, but have no such roles to play in modern times.
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