Coordinated changes of kinematics and muscle fibre properties with prolonged endurance training.

This research examines the effect of prolonged endurance training on the changes in movement (kinematics) and muscle fiber properties in horses. The study found that such training alters these features in a coordinated way, enhancing stability, propulsion efficiency, and muscle fatigue resistance, ultimately improving the horses’ athletic performance.

Study Design and Participants

• The study involved fifteen Andalusian stallions aged between 41 to 45 months.
• Five stallions were used as control subjects, while the remaining ten underwent an eight-month aerobic exercise training programme.
• The intensity of each horse’s exercise regime was customised according to a standardised exercise test.

Data Collection and Analysis

• Stride kinematic characteristics at the trot were analysed using videography techniques.
• Muscle biopsies from the gluteus medius muscle were taken from each stallion before and after the training period.
• The muscle samples were examined immunohistochemically to identify and measure fibre types and sizes.

Training Impacts

• The data analysis revealed that after the training period, stride frequency increased by 6%, while stride duration and stance time of the stride decreased by 6% and 10% respectively.
• The percentage of type IIA muscle fibres grew by 25%, while type IIX fibres saw a significant decrease of 80%. However, the percentage of types IIAX and I fibres remained unaffected by the training.
• The average smaller fibre diameters of types I and IIA muscle fibres had a significant increase, registering a growth of 13% and 10%, respectively.

Conclusion

• The study concludes that sustained endurance training can result in coordinated changes in kinematics and muscle fibre properties in horses.
• This coordinated adaptation enhances stability, propulsion efficiency, and muscle fatigue resistance, which improves the stallions’ athletic performance.