Thursday, February 17, 2011

Intervals, Intervals, Intervals…

This will be the first of many discussions on the subject of intervals.  Intervals are one of the most misunderstood areas of training yet one that attracts great attention.  The word is usually accompanied by a groan.  However, if the progression of the intervals is modulated appropriately the intervals become a welcome challenge.  Athletes quickly understand that if done correctly large increases in fitness can be obtained.  

The dictionary definition of an interval is a period of time between two points of time, events, etc.; intervening period.  In exercise it is a period of time that an exercise is performed at different levels of intensity for different amounts of time. Most people think of intervals as the High Intensity Interval (HIT) which is typically measured in seconds or a short number of minutes.  However, intervals could be much longer dependent on the desired outcome.   The challenge, from a coaching perspective, is to determine which length is most appropriate.  This is determined by level of fitness and the needs of a particular sport. I think most people look at intervals as training that is more suited to aerobic sports.  However, at Titan we have found that it is very helpful for anaerobic types of sport as well.  The benefit is seen in the speed of recovery of athletes during training and competition.    At Titan, we usually start at 20 seconds or less and then determine rest by the speed of recovery and the desired outcome.  At the Titan Center we have an Intermittent Hypoxicator which simulates altitude, we utilize this equipment to test athletes and help us determine levels of aerobic fitness.  Duration of the interval is then adjusted so that time under intensity is either lengthened or shortened as the level of fitness changes.  Really short duration intervals tax the anaerobic energy system while longer duration intervals require more aerobic capabilities. There is a balancing act in this training because one energy system helps to support the other.    We will marry the length of the intervals to the needs of the particular sport.  The mistake that most people make is either going too long or too hard early in the development of fitness so that the subsequent pain is so great that the athlete never wants to think about this type of effort again.  There is definitely a psychological aspect of intervals that must be considered when incorporating this type of intensity into a workout.

When starting interval training spend some time on developing baselines so that you know what type of output you are capable of in a maximum effort and for longer periods of time.  If you want the most sophisticated measure you may find lactate testing and VO2 max testing helpful in determining these baselines. 

This leads me to one of the most important parts of utilizing intervals: measurement of output!  Typically this is where the wheels come off the workout.  You must measure the amount of output!   If you do not, then the intensity of an interval late in an interval workout will diminish in output to such a point that there is little value.  I call this no man’s land training.  It is not hard enough for overload, but leads to overtraining and valueless fatigue.  

How do you measure output of an interval?  Time and distance is the poor athlete’s power meter.  For example you are doing sprint intervals for 20 seconds on the track.  Measure the distance you are covering during each interval. This will tell you whether you are producing more power than the previous interval.  On a slide board we use number of touches in the time of the interval and record it.  More touches mean more power produced and now you have a way to measure improvement.  It also allows us as coaches to determine if the interval should be shorter/longer, or whether there should be more rest between the intervals and also how many total intervals to perform.   The quality of the interval is of great importance. Poor output in your interval sessions will just make you fatigued with little performance value.  This can lead to the start of overtraining.   Intervals are also an excellent window into your fitness.  If you have in the past been performing much greater power outputs than the interval currently being performed then maybe you have not had enough rest since your last workout.  If we observe this lack of output we would skip these intervals and pick them up again after the athlete has had adequate rest to perform at the desired output.  In many cases if I see athletes drop off dramatically in the output of an interval they will many times be sick in the days following.  

If you are going to perform intervals in your training, one of the first things you need to think about is determining your baselines and then coming up with a method for recording the output on an ongoing basis.  This will allow you to see what type of training outside of your intervals is adding or subtracting from your performance in an interval and also what type of intervals are adding to your performance outside of the intervals.
More to come….
Train smart, have fun, and you will prevail!

Jacques DeVore, CSCS
President Titan Sports Performance

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