Posted on Tue Jan 19 2021
Principle of Reversibility
The Reversibility Principle states that athletes lose the effects of training after they stop working out; however, the detraining effects can be reversed when training is resumed. In short, While rest periods are necessary for physical recovery, extended intervals of resting will actually cause an actual reduce physical fitness. The physiological effects of fitness training diminish over time, causing the body to revert back to its state prior to training.
Detraining starts to occurs within a relatively short time period after training ceases. Approximately 10% of strength is lost after 8 weeks of inactivity, but 30-40% of muscular endurance is lost during the same time period. Researchers report athletes usually feel the effects - losses in endurance and conditioning - due to missed workouts in a relative short period of time.
The Reversibility Principle Does Not Apply to Skill Retention
Coordination is required for continuous motor skills (walking, biking, etc.). These skills appear to be stored in long-term memory with very little degradation. See Memory Techniques. Over an extended period of inactivity physical strength, endurance, and flexibility decline and eventually are lost; however, the knowledge an athlete acquired to execute motor skills and strategies is retained long after they are unable to execute the physical skills.
The challenge often concerns regaining precise timing after detraining. In other words, the motor skill programs remain intact but the body's physical tools for executing the programs become rusty and must be regained.
Applying the Reversibility Principle:
Conditioning: After taking a long break from training, begin a conditioning program to rebuild sport fitness. After several weeks of not raining, athletes should gradually increase their general conditioning/fitness before resuming the training volume and intensity previously attained.
Resting Active: During the off season, active participation in other sports or activities minimizes detraining effects and may even have some transfer or facilitation of skill acquisition. Avoid long rest periods with complete inactivity.
Returning to training: Increase exercise gradually and progressively after long periods of inactivity. Athletes should avoid performing intense workouts without first participating in a conditioning program.
Resumption of training: Athletes who are restarting their weight training will remember how to properly execute the lifts, but can sustain an injury if they overestimate the maximum weight they can lift compared to their previous best lifting performance.
Flexibility: Emphasize stretching exercises to regain previous levels of joint flexibility. This is particularly important for older adults who participate in senior sports.
Daphne Ng, Sports Consultant, Malaysia states "5 days of inactivity causes muscles to lose elasticity and aerobic capacity will decay by 5%. If you haven't been working out for 2 weeks, you will experience loss of muscle mass and strength." Refer her linkedin post on training reversibility.