Once your horse has a good foundation in long slow work, training may proceed to phase 2: endurance work. This type of exercise allows your horse to work up to the anaerobic threshold. Lactate, the chemical that causes muscle fatigue, builds up in the muscle during anaerobic work. At a certain point, levels start to rise at a faster rate. This point is considered the anaerobic threshold (also called the lactate threshold) where the body moves from aerobic to anaerobic energy. The anaerobic threshold can be used as a measure of fitness. Horses that are more fit will have a higher anaerobic threshold, as their bodies can work longer in the aerobic domain, producing less lactate. Meanwhile less fit horses will have a lower anaerobic threshold, as their bodies accumulate lactate much quicker. Endurance work allows horses to improve their fitness by working at the level of their anaerobic threshold, and thus gradually raising it.
This type of exercise can come in many forms. Hill work and underwater work (i.e. swimming or underwater treadmill) are particularly effective as they are both higher-resistance work than regular flat work, and thus provide a more intense workout in the same amount of time and space as a regular workout.
Finally, once the horse has a good base in long slow work and endurance work, fast work may be added. This type of exercise is really only necessary for horses that will be participating in sports requiring speed work, such as showjumping, thoroughbred and quarter horse racing, eventing and certain western events such as barrel racing.
When training for these types of jobs, there are two different training approached that may be taken. In the first, continuous speed training, generally the horse is not run at the goal distance or speed, but instead at a higher intensity for less time, or lower intensity for more time. For example, if it is desired that a racehorse will run at 600 meters per min (mpm) for 4 minutes, then the horse will be trained at 500 mpm for 7 minutes and 700 mpm for 1 minute.
The second training approach is interval training, which involves a longer exercise period with short breaks dispersed in between. For example, a 6-minute gallop set may be completed in 2-minute intervals, with 30-second walk breaks in between each interval. This strategy allows a horse that may not yet be able to complete a 6-minute gallop set at once to still get the same amount of exercise, and may actually decrease risk of injury. Although there are not any studies linking decreased risk of injury with interval training, it is known that risk of injury increases dramatically with fatigue. Interval training decreases a horse’s fatigue during exercise by allowing short breaks to recuperate, thus potentially decreasing the risk of injury. It is important to note that this type of training significantly reduces muscle glycogen stores, which is a major cause of fatigue. Thus, this type of exercise should not be done too frequently.
Gearing Up For The New Season With Endurance and Speed Word by Summit Equine Nutrition is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.