Wednesday, April 05, 2006

Interval Running

DO says "Just did my first interval session last nite with the MF runners... it was tough.. i mean veri siong.. my heart rate hit 178 which near my max of 181 beats!! Now .. i want to refresh my mind if it still around on why i am torturing myself with the Interval... As SC5 would say .. I saw GOD last nite..hehee..."

Most runners seeking to maximize their 5K or 10K potential will need to adopt some form of interval training. After a base of solid distance running has been established, runners can add interval training to complete the elements needed for optimal racing fitness.

Purposes of interval training
There are three main reasons to do interval training:

1. Intervals are used to increase anaerobic threshold levels. By repeating sustained hard efforts at near anaerobic condition, the runner improves his ability to run hard without going into oxygen debt.

2. Interval training also increases a runner's endurance. This means that the runner can continue at a certain pace for an extended period of time.

3. Finally, interval training builds muscle strength. Typical distance running exercises the leg muscles in a certain range of motion, with the focus on slow-twitch fibers. By running at faster speeds, the runner exercises all leg muscles and improves flexibility during running, both of which will mean improved muscle performance in races. This makes running at a race pace easier and improves top speed for sprint finishes.

While these reasons can be summed up by the maxim, "If you want to race fast you have to train fast," they also indicate (at least reasons 2 and 3) that some small amount of intervals will also benefit even fitness joggers.

The amount and distance of the intervals, as well as the frequency of the training sessions, will be determined by the quality of mileage training, the type of runner involved, and personal preference. Two principles must be kept in mind when developing a training schedule that includes intervals: 1) the intervals must complement the distance mileage training (i.e., a runner needs to identify what is missing from the mileage running), and; 2) the type of workouts must suit the runner both physiologically and psychologically.

The latter point is important, especially for runners who are no longer part of a team. It is hard enough for a runner to motivate himself to do a tough workout, let alone one that the runner does not like or do well at. In short, for a runner to benefit from interval training, he has to show up at the track. And to reliably and enthusiastically show up at the track, the runner must have interval workouts that work for him.

Physiological differences

Different types of runners will benefit from different mixes of interval training. A runner with a greater amount of slow-twitch muscle fibers will generally do better with longer intervals. Conversely, a runner with a higher percentages of fast-twitch muscle fibers will tend to do better with an interval mix that includes more shorter intervals.

The slow-twitch runner will generally need fewer interval sessions than the fast-twitch runner. Indeed, too many interval sessions can quickly fatigue the slow-twitch runner's limited number of fast-twitch muscle fibers, which results in no staying power in longer races, or the appearance of no endurance. Runners with more fast-twitch fibers will generally thrive on more interval sessions. For example, it is plausible that a slow-twitch runner would need no more than one well-designed interval session per week, whereas a fast-twitch runner would need three weekly interval sessions to maximize his ability.

That being said, for slow-twitch or fast-twitch, a runner who is seeking to maximize fitness for a 5K or 10K will need to have a significant amount of high-quality mileage or longer intervals. Most runners who have trained on a team have seen a "workout king" ?? a runner who excels at interval training, especially shorter intervals, but fails to come close to the same level during races. The usual cause of this dissonance is a lack of endurance, which can only come from quality mileage or longer intervals.
Another caution when it comes to interval training is that runners can compete with other runners or themselves during these sessions and lose sight of what they are trying to accomplish.

The runner who has plenty of quality mileage ? runs pretty hard for much of his training, includes hills in his runs, does tempo or steady state runs ? will have less need for intervals than the runner who runs easy mileage. For example, in the classic Lydiard training regime, a base of quality mileage is followed by hill repeats and then by a period of shorter intervals (200 meters to 400 meters). This works because the runner has the endurance and a high degree of aerobic fitness from his mileage. The shorter intervals add the final piece to the mix and further muscle development.

In contrast, under the old Oregon system, the endurance and anaerobic threshold were built on longer intervals (800 meters and up) and on shorter intervals with abbreviated rest periods or moderate speed recovery periods (similar to fartlek). The quality of the mileage was less important because so many other elements of fitness were obtained from the interval training.

Shorter intervals are added to the mix to provide the final element of anaerobic threshold and muscle development. In sufficient quantities and at the right pace, shorter intervals can also provide some endurance building.

The majority of short intervals will be of distances of 200m, 300m and 400m. They can be varied, like the longer intervals, or there can be a set amount at a specified pace. Like longer intervals, some runners prefer "cutdowns" ? gradually reducing the time of the hard efforts from relatively easy to very challenging.

Adding short intervals, such as 6 x 200m at a relaxed sprint, at the end of longer interval sessions or tempo runs can provide needed balance in developing overall race fitness.

Also as noted above, shorter intervals should not be the exclusive form of interval training unless the runner does a substantial amount of quality mileage. An athlete who does easy mileage and only shorter intervals will likely never develop the endurance to maintain his potential over a 5K or 10K.

From this midpoint of recovery time, runners can vary the amount rest they take depending on their workout goal. Runners who are seeking to develop a greater amount of endurance can reduce their rest periods. Runners seeking to run faster during their hard efforts (usually to increase fast-twitch muscle development) can take longer rest periods.
Generally, within a reasonable margin of the midpoint recovery period (20 - 30 percent variation), it is simply a matter of preference to determine the amount of rest between hard efforts. The margin of fitness difference between a little more or a little less recovery period is inconsequential in the overall context of training.

The next question is whether to walk, jog or run during the recovery period. Again, this should be determined by the primary purpose of the training session. Walking obviously provides more rest than jogging if the rest periods are the same amount of time. Walking for recovery might make sense if the primary goal of the interval session is to maximize muscle development. If building endurance is the main goal, a walking recovery makes little sense.

Jogging during recovery is generally preferable to walking if for no other reason than the legs stay warm and loose between hard efforts, reducing the risk of injury during acceleration. Jogging during recovery also has the added benefit of keeping the runner running, which improves endurance and the mental toughness of the athlete.

Interval training provides a level of fitness that is difficult for most runners to achieve via distance mileage alone. As with much of training, flexibility is needed in designing and performing interval sessions. Every runner is different and will react individually to different workouts. But if the purposes and principles of interval training are kept in mind, the runner should both enjoy and benefit from interval training.

2 comments: said...

wow! starting on intervals eh? next time will call u speedy DO. yeah, having done some intervals prior to KL 1/2 marathon, I can ascertain to the difficulty of this training. good luck!

DO said...

Now then u tell me... i saw GOD after my intervals... veri siong...



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