Why interval training is beneficial for performance

Intensity Training. Zone Training. Heart Rate Training. Whether we are runners, bikers, swimmers or any combination, as athletes we are constantly striving to improve our performance. We know that training at one speed produces one speed. We know about lactate threshold training and improving our VO2 max. But a real understanding of why training at multiple speeds or intensities is beneficial alludes many athletes.

There are several major adaptations that occur in skeletal and cardiac muscle in response to training.

• LSD (long slow distance) or basic endurance training (zone 1-2):
This speed is for long endurance training and base building. Most long endurance training sessions are done in this submaximal heart rate zone. Athletes can build durability, improve aerobic fitness and improve technique or efficiency of movement.

Adaptations:
The ability to sustain submaximal workloads for an extended period of time is a result of an increase in oxygen exchange and supply to the muscles due to an increase in capillaries as well as an increase in mitochondria (aka the respiratory power house of the muscle cell). This increase in mitochondria allows the body to process more fatty acids for fuel utilization thus having a glucose-sparing effect. Slow twitch endurance muscle fibers increase in numbers, become stronger and more capable to produce sustained energy at a lower caloric cost.

• Tempo or intensive endurance training (zone 3):
At this slightly higher intensity of training, slow-twitch muscle fibers as well as some fast-twitch muscle fibers are recruited for work.

Adaptations:
At this intensity, muscle fiber excitability increases producing more muscle contraction and thus force production.

• Threshold (zone 4-5a):
The threshold training zone is the most critical for improving athletic performance. This zone is just below or slightly above lactate threshold. The work effort at this zone is at one’s maximal aerobic zone with intervals at an anaerobic level. Fast-twitch muscle fibers are recruited at a higher rate to help with lactate utilization.

Adaptations:
Even though both slow (type I) and fast-twitch (type II) muscle fibers increase in number, transitional (type IIa and IIb) muscle fibers are formed. These muscles fibers have characteristics of fast-twitch muscles that contract quickly but are more oxidative like slow-twitch.

As larger muscle fibers are being recruited for work, a subsequent increase in VO2 max or oxygen flow and uptake by working muscles occurs. Not only are skeletal muscles adapting to threshold training but so is the heart. As the heart gets stronger and develops more mitochondria and vessels, cardiac output or the ability of the heart to supply more oxygenated blood to the body with each beat improves.

• Anaerobic Endurance (zone 5b):
Intensity at this level exceeds lactate threshold and is completely anaerobic and stressful to the body.

Adaptations:
As a result of short interval high intensity training, lactate threshold increases via improved lactate utilization.

Coach Mike Barnow and intensity training.
Developing a training program that incorporates the appropriate amounts of aerobic and anaerobic stress is both an art and science. Coach Mike Barnow of the Westchester Track Club has over 30 years experience and has coached nine Olympians and 40 U.S. National qualifiers.

His training philosophy is simple. Less is more. Coach Mike successfully incorporates negative split intervals in his coaching of elite athletes as well as his AG runners. He has a unique ability to know what the perfect distance is for an athlete and then asks them to produce a faster split or more power for a set distance at the end of that interval. It is this ability to hold back at the beginning of a workout that has helped many a runner to the awards podium.

On Saturday August 2, 2008, from 9-12:30 Coach Mike (for more info on Coach Mike visit www.westchestertrack.org) will be leading a running clinic at the Mohonk Preserve. The purpose of this clinic is to work individually with each runner to assess their running strengths and weakness, and to coach them through interval training designed specifically for them. For more information or to register for the clinic, please email me dorothy@TriSportsTraining.com or go to trisportstraining.com/trainingschedule.html
See you on the trails - dorothy