Cz En

Motion systems diagnostic and sports applications

Movement Analysis of Human Body During Hippotherapy

Project description:

Fig.1: 3D movement experimental investigation of human trunk during Hippotherapy - 1.

Fig.2: 3D movement experimental investigation of human trunk during Hippotherapy - 2.

Fig.3: Latero-lateral movement of rider's Occiput during one horse step.

Fig.4: Latero-lateral movement of rider's C2 vertebra during one horse step.

Fig.5: Latero-lateral movement of rider's C7 vertebra during one horse step.

Fig.6: Latero-lateral movement of rider's Th5 vertebra during one horse step.

Fig.7: Latero-lateral movement of rider's Th10 vertebra during one horse step.

Fig.8: Latero-lateral movement of rider's L1 vertebra during one horse step.

Fig.9: Latero-lateral movement of rider's L5 vertebra during one horse step.

This research project deals with movement and muscular activity analysis of human trunk during hippotherapy. Hippotherapy is method used for relaxation and balancing of trunk muscles, especially paravertebral postural muscles. Hippotherapy is a form of physical and occupational therapy in which a therapist uses the characteristic movements of a horse to provide carefully graded sensory input. This method is usually used for children with cerebral palsy and spinal cord injury treatment. A foundation is established to improve neurological function and sensory processing, which can be generalized to a wide range of daily activities. Unlike in therapeutic horseback riding, where specific riding skills are taught, in hippotherapy the movement of the horse is a means to a treatment goal.

In order to solve this task, telemetric surface EMG and 3D motion analysis were used. It was necessary for objective results of this experiment, to exclude all pathology of experimental person and experimental horse. To assure the straight transmission of motion impulses from horse back to the rider only the trick-riding pad was used for the experiment instead of the saddle. Trick-riding pad is a special pad with smooth surface used for hippotherapy and trick-riding. This pad assures maximal contact of both the horse and the rider. The selected horse was routinely used for hippotherapy and experiment was filmed in his home grassy paddock.

  The body of experimental rider had installed markers on anatomical significant points (proc. spinosus of vertebrae C2, C7, Th5, Th10, L1, L5, acromion, spina scapulae, etc.) for movement identification. Also measured specimen had installed surface EMG electrodes on dorsal, ventral and lateral muscles stabilizers of trunk (paravertebral muscles, m. rectus abdominis, m. obliquus abdominis internus et externus). Self-adhesive diagnostic surface electrodes Biotabs Ag (MIE, LTD., UK) were used. Electrodes were connected to EMG preamplifiers. EMG signal led into an EMG transmitter. We used six channels for EMG signals and seventh channel for synchronization with cameras. A receiver was telemetric EMG MTR8 (MIE, LTD., UK). Raw electromyograms were bandpass filtered (20-500Hz), rectified, and smoothed (using a RMS window of 75 msec). Raw maximum voluntary isometric contraction EMGmax data were processed similarly, and used to normalize the EMG data associated with the trunk movements. Outdoor 3D motion of rider’s trunk was experimentally analyzed by four video recorders and then processed with APAS software (Ariel Dynamics Inc.). Simultaneously with an experimental measurement of movement parameters were recorded EMG’s. The experimental area was calibrated for 3D analysis and later movement simulations. For the camera calibration and marker position computation was DLT method used. The clapper was used for cameras and EMG synchronization. For video motion analysis four digital video recorders Sony DCR-TRV 900E were used. A record frequency was 50 half frames per sec. From video records were obtained coordinates of before mentioned points and from this coordinates were computed other geometric and kinematics parameters of horse-rider movement. Movement analysis provides the visual information about horse walking phases and quantification of rider's trunk motion. Both of these are being passed to create a correlation between rider trunk motion and EMG signal from trunk stabilizing muscles obtained from 8-channel telemetric EMG.

The existence of correlation between the change time depending of muscular activity and the trunk movement in relation to step phase of horse walk was detected. Trunk movement was represented with anatomical significant points. It is especially concerned dorso-anterior movement and partly lateral movement. We can characterize this correlation as a reaction of stabilizing muscles on opposite lateral escape of rider’s trunk that has been generated by movement pulses of horse trunk.

  There is markedly different course between trajectories of all vertebras in the upper part of the spine and trajectories of vertebras in the lower part. Figs. 3-9 shows, that this fact corresponds to the investigated different courses of lateral shift of both upper and lower parts of a spine. Vertebra L5, L1 and Th10 circumscribe during whole horse walk twice ellipse with identical left-right shift – analogy of sinusoid curve. Vertebras C7, C2 and Occiput circumscribe a loop, which describes increase, right side shift with decrease and return to the original position – analogy of curve describing their latero-lateral shift.

By this experiment was the movement of whole horse-rider’s spine during horse walk described. Was detected that horse's pelvis has the same three dimensional movement of the human's pelvis at the walk. The vertical movement provides the same attributes for all investigated points while the lateral shift is variable for each point. Side shift of lumbar spine correlates with horse trunk movement. Its course is sinusoid shaped and this curve is completed once during the horse walk cycle. The upper spine is moving with different frequency and range of motion then lower spine. During one horse walk cycle occurs only a little side shift. The middle part of spine creates kind of mid-point of contrary side shifts of upper and lower spine.

Whole spine movement correlates in vertical plane with the movement of horse trunk while lateral movement can be characterized as waving. This waving originates from horse back motion during horse walk and is transmitted upwards to the upper parts of spine.

During horse walk occurs change of left-right shift of vertebras so, that waving can be described and their approach and extend was observed.

In the future, would like to focus on the variability of horse gait. We assume the variability of the horse's gait enables the therapist to grade the degree of input to the patient and use this movement in combination with other treatment strategies to achieve desired therapy goals or functional outcomes.

Miloslav Vilímek, Tomáš Goldmann PhD