Effects of a draft-loaded interval-training program on skeletal muscle in the horse.

The research studied the impact of a particular interval training program involving resistance, on the muscle fibres of five Standardbred horses. The conclusions indicate that such a training regime induces rapid changes in one particular muscle of the horse.

Research Design and Methodology

• The researchers used five Standardbred trotters within their study. These horses were trained on a treadmill three times per week for a twelve week period. The training used intervals of draft-loaded exercise, where horses pulled a light resistance at a submaximal trotting speed.
• The draft load for the exercises was set to 34 kp and the velocity was approximately 7 m/s.
• The researchers collected muscle biopsies from three different muscles of the horses. These muscles includes-gluteus medius, longissimus muscles and brachiocephalicus muscle. These samples were collected before the start of the training program and at two, four, eight, and twelve weeks into the training regime.

Findings of the Study

• Results from the study showed that the percentage and the area of type IIa muscle fibers in the gluteus medius muscle increased during the first two weeks of training, while the percentage of type IIb fibers decreased. No significant differences were noted after this two week period.
• In the brachiocephalicus muscle, the percentage of type I fibers increased. Furthermore, the area of type IIb fibers saw an increase in the longissimus muscle.
• Citrate synthase activity was seen to increase in the gluteus muscle, but only during the first two weeks of training.
• There were no significant differences noted in the 3-hydroxy-acyl-CoA dehydrogenase and lactate dehydrogenase activities in any of the muscles throughout the entire training period.
• The study also found that less glycogen was utilized in the gluteus muscle and less blood lactate accumulated when the horses performed an unloaded submaximal exercise test after the training compared with before the training had begun.

Conclusion

• The conclusion of the study showed that this type of draft-loaded interval training can quickly induce changes in the gluteus medius muscle when horses are trained pulling a resistance at a submaximal trotting speed.