Cardiovascular, respiratory and metabolic effects of interval training at VLA4.

The research article explores whether short interval training at a particular velocity (VLA4), which produces a lactate level of 4 mmol/l, can lead to improved physical adaptations and exercise tolerance. The study was conducted over 16 weeks wherein five horses were trained three times a week for 12 weeks and then stopped training for 4 weeks. The results indicated improvements in heart rate response and lactate levels, among other measures, indicating that training at VLA4 could potentially enhance exercise tolerance.

Methodology

• The study involved five Standardbred mares in the age range of 4-8 years. These mares were put through interval training on a treadmill three times a week over 12 weeks.
• Following the 12 weeks of training, the mares underwent a detraining period for four weeks.
• Standardized exercise tests were performed before, during, and after the training period, and muscle biopsies were collected.
• The researchers monitored several factors such as heart rate, oxygen consumption, stride frequency, blood volume, and blood lactate levels.

Results

• The plasma volume of the mares reduced after the initial two weeks of training but slowly increased to pre-training values over the continuation of the training and post-training periods.
• The total cell volume remained unchanged, while the total blood volume varied along with the plasma volume.
• After 4 weeks of training, a significant reduction in the heart rate response to exercise was observed.
• VLA4 enhanced after 2 weeks of training and maintained higher than the initial value throughout the training period.
• Post-training VLA4 didn’t significantly change from the pre-training or end-of-training values.
• The oxygen consumption related to mass (VO2-200/BW) at V200 increased with training and decreased post-training.
• The respiratory quotient at a velocity of 8 m/sec dropped from 1.18 +/- 0.02 before training to 1.07 +/- 0.02 (P < 0.05) by the end of training.
• No modifications were noted in muscle histo- or biochemical metrics.

Conclusion

• The findings of the study suggest that interval training at VLA4 can result in adaptations leading to improved exercise tolerance.
• Such adaptational changes were indicated by factors such as lower heart rates, increased oxygen consumption, and decreased blood lactate levels at higher velocities.