Reversibility
The 8 Principles of Training
The Principle of Reversibility refers to the loss of fitness due to inactivity.




How the Principle of Reversibility Applies to Weight Training
The Principle of Reversibility is well-grounded in exercise science. The biological principle of use and disuse underlies this principle. Simply stated, If you don't use it, you lose it.
While rest is necessary for recovery, long rest intervals reduce fitness. Training effects are reversed.
The effects of detraining occur within a short time after you stop training. Only about 10% of strength is lost 8 weeks after training stops, but 30-40% of muscular endurance is lost during the same time period. See Principle of Recovery
The detraining effect occurs within your muscles after you stop training, so the strength and shape that you developed when you overloaded your muscles diminishes over time. The good news is that you can reverse the situation and get back in shape. Many believe that muscle memory helps you regain fitness more quickly than it took you the first time.
This principle does not apply to retaining skill. The effects of stopping practice of motor skills, such as weight training exercises and sport skills, are very different.
Coordination appears to store in long-term motor memory and remains nearly perfect for decades, particularly for continuous skills (e.g., riding a bike, swimming).
A skill once learned is never forgotten, especially if well learned. If you stop training, over time you will lose strength and endurance, but you will remember how to execute the skills.
Examples of How to Apply the Principle of Reversibility
- After long rest intervals, begin a conditioning program to rebuild your base of strength, endurance, and other fitness components.
- Do not attempt lifting heavy weight loads (e.g., maxing) without proper conditioning after a break. Your technique may be fine and you may feel strong, but miscalculated detraining effects could cause you to suffer an injury.
- Take an active rest to minimize the effects of detraining during a break.
Understanding how to apply the Principle of Reversibility will help you retain the training effect of your weight lifting workouts.
To learn about the principles behind developing your desired training effect, see the Principle of Specificity and the Principle of Overload.