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Detraining: Definition and Examples

What is Detraining?

Detraining is the partial or complete loss of training adaptations (e.g., strength and muscle mass) in response to taking time off training or reducing the training volume and intensity. The extent depends on how much time someone takes off training and the person’s nutritional habits. Athletes can reverse detraining once they return to structured training and eating, usually within weeks or months.

A Deeper Look at Detraining

The body adapts to the type, intensity, and volume of training. For instance, if someone runs a lot, they build cardiovascular capacity; if they do barbell training, they build strength and muscle.

How quickly adaptations occur depends on many factors, including the trainee’s genetics, experience, nutrition, recovery, and effort. 

However, when athletes stop training due to injury, illness, or other reasons, they lose the previously gained fitness adaptation—endurance, strength, power, and muscle mass decrease. 

This process makes sense from a physiological standpoint because the body adapts to physical stress. When that stress decreases or disappears, the body no longer has a reason to maintain these adaptations.

How Long Does Detraining Take?

First, the good news is that a few days of not training don’t seem to impact fitness adaptations. 

Two or more weeks of not training might also not impact fitness, particularly for strength and muscle mass. In one study on teenagers (average age 16), three weeks of detraining following a block of training (daily undulating periodization) didn’t result in any strength or muscle losses.

That said, some research from Chen et al. suggests that two or more weeks of detraining reduces cardiopulmonary functions (the body’s ability to deliver oxygen to tissues) in endurance athletes.

Beyond that, time spent away from working out will result in detraining. Factors that may influence this include:

  • Nutrition – does the athlete eat enough calories to support body weight and enough protein for muscle tissue (vital for holding onto muscle)
  • Sleep – poor sleep is linked to increased protein breakdown (i.e., loss of lean tissue, such as muscle)
  • Activity – being active during the day but not doing any structured training is still better than if a person is completely inactive (e.g., spending all the time in bed)


1. Are the effects of detraining the same for everyone?

The effects of detraining differ between individuals, depending on the athlete’s fitness level, experience, physical activity outside of structured training, nutrition, and sleep.

2. What physiological changes occur during detraining?

Detraining is specific to the athlete’s adaptations, which means it’s different for everyone. However, some general changes include a reduction in VO2 max, loss of muscle (and glycogen storage capacity), body fat gains, and a decrease in insulin sensitivity.

3. How can athletes minimize the effects of detraining?

The best way to minimize detraining is to continue doing structured training instead of stopping completely. Additionally, being more physically active during the day and eating enough protein (at least 0.7 grams/lb) can also help.

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