One week of detraining results in a loss of about what percentage of gains from five weeks of training?

• A. 10%
• B. 25%
• C. 50%
• D. 75%

Answer: (C)

Detraining reverses adaptations quickly, so a short break can erase a substantial portion of what you gained. After seven days without training, you often see about half of the improvements from a five-week program fade. This happens because neural adaptations that boost strength and rate of force development fade rapidly with inactivity, and some early hypertrophic gains and metabolic changes begin to regress too. Muscle glycogen storage, enzyme activity, and other cellular adaptations decrease, which lowers performance and strength. The reversibility of training stresses that gains aren’t permanent if the stimulus is removed, and the amount lost in a week reflects how quickly these adaptations can roll back. While individual differences exist, the common teaching point is that roughly half of those five-week gains can be lost after a week of detraining.