Whether it's off-season, an injury, burnout or deployment, sometimes your weight training regimen falls prey to circumstances beyond your control. While you may welcome a break from grueling hours at the gym, be prepared to lose strength and size as well. As it turns out, the link between strength and exercise is a powerful one.
Muscle Hypertrophy and Strength
When you lift heavy weights, the overload placed on the muscle causes individual muscle fibers to adapt by increasing in diameter, resulting in an overall increase in muscle size. The storage capacity within the muscle cells for creatine phosphate and glycogen, the fundamental fuel sources for ATP synthesis, also increases. Other adaptations that take place include stronger bones and joints and improved neuropathways between the central nervous system and muscle motor neurons. But holding on to these changes takes work.
When you stop exercising, the adaptations that resulted from all your hard work begin to disappear, a process called detraining. The Human Kinetics publication "Essentials of Strength Training and Conditioning" defines detraining as "Cessation of anaerobic training or a substantial reduction in frequency, volume, intensity, or any combination of those three variables that results in decrements in performance and loss of some of the physiological adaptations associated with resistance training." In other words, when you snooze, you lose.
The Detraining Process
According to the American College of Sports Medicine's publication "Primary Care Sports Medicine," a "swift and significant" detraining effect occurs for athletes after only two weeks of exercise cessation, with a measurably "significant reduction in work capacity." The book "Physiology of Sport and Exercise" by Wilmore, Costill and Kenney concurs that for highly trained individuals, the detraining process is rapid. However, a total return to pre-training status takes much longer for exercise neophytes, possibly as long as seven months to lose gains from a nine-week weight training regimen.
Detraining vs. Reduced Training
While a complete cessation of training will cause significant losses in strength, a reduced frequency and volume of training combined with increased intensity has been shown to be effective for maintaining strength levels. In a study of 46 physically active men published in the Journal of Strength and Conditioning Research, a 16-week strength training program was followed by four weeks of total cessation by some of the subjects, while others continued with a 'tapering" regimen consisting of decreased total volume of exercise, but increased intensity. The group who totally stopped training saw a marked decrease in overall strength while the tapered group actually saw increases in strength due to the higher intensity.
Holding on to Strength
If you must be away from the gym, look for opportunities to do small amounts of high-intensity exercise. Pullups, pushups, and step-ups all work multiple muscles and can be performed with minimal or no equipment. Returning to your full training regimen will be easier and a lot less painful if you don't allow your body to totally detrain.