It is often heard that muscle is built while resting, not in the gym, but what does this really mean? In brief, this statement extrapolates from the fact that the anabolic response to exercise is largely postponed until after exercise has already taken place and requires some time to take full effect.

Damage Control - Allow Enough Time to Rebuild
Intense exercise causes some muscle damage. These areas of micro-damage are an obligatory prerequisite for muscle growth. That is, muscle repair and growth depends on preexisting muscle damage caused by exercise. Given sufficient recovery time and appropriate nutrition the amount of new muscle tissue produced may then exceed the previous level and your muscles will increase in overall size. In essence, this is the biochemical basis for bodybuilding - that is, if all goes well. If, on the other hand, sufficient time is not allowed for muscles to fully recover, or if nutrition does not supply the needed amounts of substrates to support new muscle synthesis, then the growth phase will be blunted. Excessive exercise furthermore, will destroy already damaged muscle before it has a chance to rebuild; we then enter a state of negative muscle growth (net muscle loss), a condition known as Overtraining Syndrome. In essence, building muscle is a tradeoff between resting too little, which destroys overexerted muscle, and resting too much rest, which does not stimulate muscles sufficiently to provoke functional adaptation.

Rotate Muscle Groups for Optimal Recovery
Depending on the intensity of the exercise and physical condition of the athlete anywhere between three and seven days are required for muscles to fully recover. This isn’t to say, however, that one should work out only once per week – this would be nearly as ineffective as overtraining. Consequently, most athletes adopt exercise routines that rotate muscle groups every few days. In this manner an athlete can train daily, improving cardiovascular conditioning as well as the efficacy of neuronal communication with muscle, while working each individual muscle group at most twice per week.

• Those of you wanting more detailed information about effective training routines for increasing muscle mass are kindly referred to the banner on the upper right (”Need More Muscle Mass?“). The creator of this effective muscle-gaining program is Anthony Ellis, a trusted friend of mine.

Hormonal Response to Exercise
Testosterone, Insulin and Growth Hormone, our three major anabolic hormones that are released by exercise have effects that are delayed at onset and protracted in time course. They thus play a major role in muscle rebuilding after exercise. Testosterone is released by an exercise stimulus and promotes the production of new muscle proteins as well as slows the loss of existing muscle proteins. Insulin enhances the uptake of nutrients such as glucose, amino acids and creatine into muscle cells, particularly after exercise. In this capacity, insulin provides the substrates for the production of new muscle proteins as well as helps replenish our creatine and glycogen reserves. Both glycogen and creatine are important energy sources during intense exercise lasting more than a few tens of seconds – the presence of these energy molecules will be important to get the most from your next workout. Growth hormone is a key player in our anabolic hormonal response to exercise. Growth hormone is released following exercise as well as during nocturnal phases of deep sleep. In fact, the bulk of our whole body tissue repair occurs while we sleep. If you want to build muscle be sure to get plenty of sleep each night, particularly after training days.

Insulin-Like Growth Factor 1
Growth hormone’s anabolic effects on muscle is largely mediated by Insulin-like growth factor type 1 (IGF-1), which accentuates the cell’s biosynthetic machinery as well as turns off the reading of those genes that provoke muscle atrophy, the so-called “atrogenes”. On the other hand, these atrogenes are activated by overtraining via the actions of cortisol, an anti-anabolic (catabolic) hormone released by various forms of stress. Therefore, insufficient rest, sleep deprivation, and daily stresses counteracts the biosynthetic response to IGF-1. Exercise also directly stimulates muscle to produce IGF-1 independently of Growth Hormone. The biosynthetic affects of our anabolic hormones (Testosterone, Insulin and Growth Hormone) and IGF-1 can last up to a few days after the initiation of exercise - long enough to repair the damaged muscle.

• A page describing the anabolic attributes of growth hormone can be found here: http://www.creatinemonohydrate.net/growth_hormone.html

Interestingly, creatine has been recently shown to stimulate IGF-1 production, independently of exercise and Growth Hormone. However, to get the most from this intriguing effect of creatine you will need to supplement after exercise when insulin is most effective at delivering creatine, carbohydrates and proteins to your muscles. Hence, a post-exercise meal of defined composition is imperative for muscle growth.

• How to supplement for the greatest anabolic effect is explained in my creatine guide: http://www.creatinemonohydrate.net/creatine_guide.html
• More about the effects of creatine over IGF-1 production can be found here: http://www.creatinemonohydrate.net/creatine_newsletter_33.html

Overtraining Syndrome
Overtraining is a trap that many overzealous athletes fall into. Overtraining can put a stop to an athlete’s gains in strength and muscle mass and in some cases even reverse existing gains. Overtraining causes the release of cortisol, an atrogene-activating hormone that interferes with the body’s utilization of Testosterone, Insulin, Growth Hormone and IGF-1. This set of circumstances gives rise to a catabolic (muscle wasting) condition known as OverTraining Syndrome (OTS). Taking a break from training, while the wisest response to OTS, is one of the most difficult measures for an enthusiastic athlete to undertake.

Closing Remarks
The importance of rest for muscle growth extends from the fact that the muscle damage brought on by exercise needs to be repaired and further fortified with the assistance of our anabolic hormones that require a few days to fully exert their muscle-building effects. Inadequate recovery, on the other hand, hinders this process, potentially resulting in net muscle loss, a physiological condition known as Overtraining Syndrome.