Thursday, January 01, 1998

Anaerobic Conditioning - Susan Garlinghouse

Mike Sofen wrote:

For endurance riding, does anaerobic conditioning increase the overall aerobic condition of the horse? So the question is - is this an effective strategy for a fit endurance horse that could be ready to move to his next level?

Hey Mike,

Boy, this is one subject that you could write an entire book about, but I`ll try (for a change) not to turn this into four hours worth of reading.

One of the things to keep in mind is that there really isn`t a clear demarcation of now-we`re-aerobic-now-we`re-anaerobic. The actual "line" between the two is defined as a ratio of the amount of O2 being inhaled and carbon dioxide exhaled, which isn`t really important for this discussion. Just remember that it`s more of a gradual shift from one energy system over to the other. So when you`re increasing the exercise level into the anaerobic levels, you`re still utilizing the aerobic metabolism---it`s just that the anaerobic mechanisms have kicked in to make up the shortfall in energy demand.

The main thing about conditioning is to spend most of your time doing the type of work that you will be doing during the competition---in other words, for an endurance horse, condition most of your time aerobically. However, once your horse has an excellent LSD and aerobic conditioning base, then yes, you CAN sharpen his level of conditioning by adding in some anaerobic work, such as galloping hills, or whatever it takes to push his heart rate up to anaerobic levels (which is going to vary widely among individuals). What you will do through anaerobic exercise is SOMEWHAT increase the efficiency and capacity of the cardiovascular and hemotological systems that move oxygen from the lungs to the muscle and organ tissues; increase the total cardiac output a bit; and increase the efficiency of all the various systems that are designed to get blood around the body. However, you will actually get comparatively little additional benefit from exercising at maximal (anaerobic) levels than you already have received from exercising at submaximal, aerobic levels. I know there are some human exercise physiologists on the list that are getting ready to argue that the cardiovascular and oxygen-transport benefits from maximal exercise are more significant than that, and in humans, they are. However, horses are unique critters and don`t respond to submaximal and maximal exercise the same way that humans do---they`re already designed to be such superb cardiovascular athletes that once you`ve conditioned them aerobically, there just isn`t that much more response you`re going to get from the cardiovascular system as a response to maximal exercise, as you WOULD see in human athletes.

What you ARE going to do primarily is increase the efficiency of the anaerobic metabolism---the intracellular system that produces energy without oxygen. There will be an increase in production of the enzymes required for anaerobic glycolysis, and in turn an increase in the amount of total energy that can be produced at any given time during anaerobic exercise. This means, that in a sprint to the finish, for example, the horse that has done some anaerobic training is going to be able to produce more ATP and therefore more muscle contractions than the horse than has trained exclusively at aerobic levels.

You are also going to increase the maximal lactate concentrations tolerable before failure. Most everyone on this list knows by now that during anaerobic exercise, you produce lactic acid as a by-product. Lactic acid is just that, an acid, and the pH of the muscle cell starts to fall (become more acidic) as production and cellular concentration increases beyond what is being removed from the cell. The enzymes responsible for anerobic energy production are pretty picky about what pH they`re willing to work at, so as the pH becomes increasingly more acidic, the enzymes become less and less efficient (fatigue), and eventually energy production stops altogether (failure). Generally, you can only reach this very extreme point of exhaustion when playing around with electrically stimulated muscle cells in the lab in little petri dishes. When you go out and exercise yourself, you can feel the "burn" in your muscles as the level of exercise increases and if you keep going for as long as you can, eventually the pain will stop you, usually before actual muscle failure.

So, if you exercise at anaerobic levels on a somewhat regular basis, you will get the muscle cells used to operating under somewhat acidic conditions---as a result, the time to fatigue and failure during maximal exercise will be increased. Please notice that this is not a recommendation to go out and gallop your horse into exhaustion. Use common sense here as in everything else.

One other thing to keep in mind, however, is not to overdo the anaerobic conditioning. If done too much, the horse`s body will become better suited to anaerobic exercise than aerobic exercise, akin to a Quarter Horse that can sprint like hell for a few hundred meters, than quit. Obviously, for an endurance horse, you just want to sharpen up all the toys in the toybag, not start to replace the aerobic mechanisms with the anaerobic ones. Most endurance people know about slow-twitch and fast-twitch muscle fibers, and that Arabians have a higher density of slow-twitch fibers and that`s why they`re better at endurance as a breed than say, your average Percheron. However, besides just slow and fast-twitch, there are also numerous classes of intermediate fibers that will respond to the type of exercise by leaning more towards becoming either a slow-twitch or fast-twitch fiber (not totally, just sorta). If you`re exercising primarily at aerobic levels, the intermediate fibers will help out by gradually acting more like slow-twitch fibers. If you exercise alot at anaerobic levels, they`ll start acting more like fast-twitch fibers, thereby decreasing your aerobic performance.

So, the bottom line to all this, is that yes, you can improve performance with some judicious anaerobic conditioning. You`re not going to affect aerobic performance very much, if at all, you`re just going to increase the anaerobic capacity. This increased capacity is probably of the most use to the competitor who is expecting to spend some time during the race racing at maximal, anaerobic levels, such as during an all-out drive to the finish. For the majority of riders who just want to complete, even finish within the top half or third of the pack, it`s of less value, and there is something to be said as well for avoiding the increased risks of injury that come along with maximal effort. For most folks, alot of aerobic conditioning is going to fill the bill. If you`re a hotshoe AND HAVE ALREADY DONE YOUR HOMEWORK IN THE LSD DEPARTMENT, then adding anaerobic to the exercise regime will add a nice final edge.

Hope this helps and wasn`t hopelessly confusing.
Susan Evans Garlinghouse

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