As a coach of 25 years and life-long competitive athlete, I am not immune to being frightened by this irrational fear myself. I’ve gotten sick, experienced a niggling injury and had to miss chunks of training for some other reasons as well. Being emotionally invested in the process of improving my athletic performance, it becomes very challenging to listen to reason and the scientific evidence, and comprehending that a few days off will not negatively impact fitness or progress.
When we look at the effects of taking time off from training, it’s important to analyze the detraining from two perspectives: (1) your metabolic systems such as aerobic fitness, threshold and VO2max; and (2) your structural systems such as your muscles and neuromuscular coordination (how fast and efficiently your brain can tell your body to perform and execute a specific movement).
Impact to the Aerobic System
VO2max is a solid measurement of fitness. Effectively, VO2max is the body’s ability to transport and use oxygen during exercise. Multiple studies show there is little reduction in VO2max during the first 10 days of inactivity in well-trained athletes. After about 14 days, VO2max decreases by about 6%, and after 8-10 weeks it drops by about 20%. Looking at this another way, even if you sit on the couch for up to 2 weeks, the effects of detraining are minimal to non-existent. A 5-6% reduction in VO2max can be recouped in as little as a couple weeks of solid training.
Impact to the Structural System
There isn’t a lot of research to find here. What I could glean states that detraining to the sport-specific muscles, connective tissue, etc. occurs in the 10-day to 4-week range. Fewer than 10 days and there’s really no negative impact from the downtime, and after a month it tends to level out. Muscle strength and power both decline at a slower rate than the aerobic system.
Do I Need to Worry?
The punchline of all this is that you shouldn’t be too worried about “losing fitness” simply by taking a day, multiple days, or even a week off. After about 10 days, you will lose some conditioning to both your aerobic system and musculature, but that lost fitness will be minimal and will return quickly once you are back up to a full training program.
It is never fun to experience a forced break from training. We look in the mirror and see the flab spontaneously generating while our muscles atrophy like sand spilling between our fingers. This is most definitely not the case. So, the next time you take a break – planned or unplanned – take a deep breath, relax and try to avoid generating mental and emotional stress to compound what you’re going through.
In Part II, I will provide some suggestions on how to return to full training volume and intensity after an extended break during the competitive season.