The performance testing included a treadmill run to fatigue, with the treadmill speed set at the individual runner's best 1500-meter time. Strength and contractile properties of the quadriceps muscles were measured before and after each taper. Muscle glycogen concentration, citrate synthase activity using needle biopsies, total blood and red cell volume were also measured.
The results:
- Strength increased after all three tapers.
- Only after ROT and HIT did muscle glycogen increase.
- Total blood volume increased significantly (statistically) after HIT, but decreased after ROT.
- VO2 max was unchanged by all three tapers.
- Citrate synthase—considered a pace-making enzyme in the first step of the Citric Acid or Krebs Cycle—activity also increased significantly after HIT and decreased after ROT.
Finally the marker most athletes are concerned about, performance running time to fatigue, increased significantly after HIT (+22 percent). Scientists noted that performance was considered unaffected by LIT (+6 percent) and ROT (-3 percent).
Multiple studies have been completed on the physiological and performance benefits of tapering for the individual sports of swimming, cycling and running—certainly too much information to review in this column. As an example of the volume of information, one study in Sports Medicine had a page-long list of the physiological changes that occur during taper.
These physiological changes go deep. One study on cyclists in Medicine & Science in Sports & Exercise found that tapering affected metabolic changes of the muscle at the single fiber level.
More: What's an Ideal Taper for Cyclists?
Training Taper Studies on Triathletes
Several studies look at the physiological changes of tapering on the individual sports of swimming, cycling and running; however, there are not many actual scientific studies on the training taper in triathletes. I suspect this is, in part, due to the complications of managing three sports and all the variables.
One study that I found, "Training theory and taper: validation in triathlon athletes" concluded that an exponential decrease in training volume was better than a step-reduction. That study also concluded that a fast exponential decay was better than a slow decay. I'm assuming from the abstract that swimming, cycling and running were all decreased at the same exponential rate. Keep in mind, however, that this is a single study.
More: Listen to Your Body to Avoid Injury
Just to give you one glimpse at the differences, and complications, between sports and distances, one study on swimmers in the Journal of Strength and Conditioning Research found that those that included a 20- to 30-percent increase in volume at the end of a two-phase taper performed better than those that did a linear taper in volume.
A separate study on Ironman triathletes in the journal of Advances in Experimental Medicine and Biology, however, found that bumping volume up at the end of taper and in the immediate days preceding the event did not yield positive results. The study concluded, "proper placement of training during taper is a key factor in optimizing performance."
Indeed.
