Most athletes know that to perform better in a competition, it’s a good idea to start backing off on the intensity of their training a week or so before the event. By cutting back 7 to 21 days before a big heat, they can still gain increased endurance and muscle strength. This method often results in a 2-4% performance improvement. Likewise, working out too hard right up to the event leads to a drop in muscle strength and poorer performance.
Researchers sought to understand more clearly why this happens. To get some answers, they studied the changes that happen inside the muscle fibers of swimmers who tapered their training sessions before a heavy competition.
Six highly trained college swimmers volunteered for the study. Twenty-one days before a major swim competition, they starting easing off on the overall intensity of their workouts. They still pushed hard with interval training, but their total distance during training sessions was a lot less than before.
Researchers measured how hard and fast each swimmer could go while swimming against heavy resistance. The authors also did muscle biopsies of each swimmer’s upper arm muscles before and after the change in training. A muscle biopsy is done by using a needle to take a tiny sample of muscle cells. Ouch! Now you understand why they only had 6 volunteers! The researchers compared the muscle cells using a microscope to see if there were any changes over the
21-day period.
Of the two main types of muscle fibers, the microscope showed that only one type was particularly affected. The Type IIa fibers had more power and speed in their spring. These are the muscle cells that give short bursts of energy for high-intensity actions like sprinting and lifting. The microscope also showed that these fibers were bigger across in size after the 21-day training period. Interestingly, these same fibers shrink in size when athletes work too hard right up to the time of competition. With the improved spring and larger size in their Type IIa muscle cells, the swimmers had stronger muscles and performed better.
Another type of muscle cell is the Type I muscle fiber. This cell gives the body endurance to work for longer time periods, such as during a long walk or jog. The Type I fibers seen on microscope showed little change after either intense training or after tapering down on training. Studies like this build a case for swimmers to taper their training programs before they compete. Future research is needed to confirm whether these results are similar for other types of sports.