School has started back in session and many local athletes have already begun their competitive seasons for their high school teams. While the most common thought is that you do your conditioning in the off-season and play during the in-season, this practice is out-dated and ensures that fitness and physical capacity are at their lowest at the time when they need to be highest (at the end of the season). Physiological markers of fitness and performance can drop off with as little as 5 days of deconditioning. 5 days…that’s a long weekend holiday. Here’s a quick detraining timeline:

  • Days 1-2: Beta-endorphin and adrenaline levels drop. Mood is affected negatively.
  • Days 3-5: Muscles lose elasticity. Aerobic capabilities drop off 5% by the fifth day off.
  • Days 7-9: Body’s ability to use oxygen (VO2 max) drops by 10%. Less oxygenated blood is pumped with each beat.
  • Day 10: Body’s metabolic rate begins to drop. Eat less or you’ll gain weight.
  • Days 11-13: Maximum heart rate and cardiac output decline by 15%. Muscle tone sees first appreciable loss.
  • Days 14-16: Mitochondrial activity (energy production) in muscle cells begins to decrease rapidly. Loss of muscle mass, strength and metabolic rate occurs.
  • Days 17-19: Body becomes less efficient at thermoregulation. You are forced to spend excess energy cooling off.
  • Days 20-21: VO2 max has dropped by about 20%.
  • Days 22-25: 10-15% loss of muscle mass and that lost mass is replaced by fat.
  • Days 27-29: Muscle strength has declined by as much as 30%.