We all recover from exercise at different rates. Many people who recover quickly have reached a high level of success performing a high number of sets. Many who recover slowly have also been very successful performing low numbers of sets. Because everybody is unique in their ability to adapt and recover from different programs, the number of sets needs to be individualized.

A very important component of a training program that should be given consideration is training frequency. How often can, or more importantly, should I train per week? Optimum recovery time between training sessions is essential if one is going to continue to make progress. Training frequency, which is determined by ones recovery ability, is often a forgotten part of most training protocols.

Don’t be so concerned with how many training sessions you can handle per week. Be more concerned about the optimal amount. More is not always better. In fact, when somebody comes to me for advice because they’ve stopped making progress, usually I either reduce the workout volume or add days off. There is no reason to go to the gym if you’re not going to make progress.

Does it make sense to keep doing the same routine if gains are not being made? Isn’t the definition of “crazy”, doing the same thing over and over expecting different results. If your current program is not working, change it. The number one complaint people have is they’re not making progress or their progress has come to a halt. In both cases, the answer is more recovery time. Understanding the fact our bodies have a finite amount of recovery ability should help explain this concept.

The following is Mike Mentzer’s explanation of overtraining and recovery. I’m sure you’ll find it interesting.

In bodybuilding, the idea is to impose a training stress onto the body that will serve to induce the biochemical changes which result in muscular hypertrophy. Applying any more of the training stress (high-intensity) than is required by nature will result in the equivalent of over-dosing on a medicine; or, as we say typically in bodybuilding – overtraining.
A person exposed to the sun’s ultraviolet rays at the equator in summer would not have the slightest concern whether the intensity of the sunlight stress is high enough to disturb the physiology sufficiently to induce an adaptive response, i.e., the buildup of a suntan. His only concern, his overriding consideration, would be to properly regulate the volume (or duration) and frequency of exposure time so as not to overdose on the stress/stimulus; and, thereby, incur a sunburn or, in extreme cases, death. A person seeking to develop a suntan at the equator, or wherever the intensity of the sunlight is high has no concern that he will develop a suntan; but only if he doesn’t overexpose. (Note that bodybuilding science is largely based on the medical discipline of stress physiology. Also, that the end result of the healing of a sunburn is not a suntan, just as the end result of the healing of overtraining is not greater strength or added muscle.)
As the stresses grow progressively greater, they will eventually reach a critical point such that they constitute overtraining. The first symptom will be a slow down in progress; and if the individual continues with the same volume and frequency protocol, the stresses will continue to increase until there is a complete cessation of progress, typically referred to as a “sticking point.” One need not ever experience a slow down in progress, let alone a sticking point, if he bears in mind all the while that as the weights grow progressively greater so do the stresses; and he must do certain specific things to compensate for them.

MikeMentzer.com

A training program in the form of progressive resistance exercise builds muscular size and strength. In order for a training routine to be productive, however, it must first provide the correct stimulus to induce an adaptive response. Second, a workout that stimulates and adaptive response must provide for recovery. Third, in order for recovery and subsequent size and strength increases to occur, nutrients, which are of limited supply in our bodies, must be provided. It is clear that the most important nutrient for recovery is protein. In particular, essential amino acids contained in complete protein sources; dairy, meats, and fish. It is well documented that essential amino acids consumed before, during, and after resistance training boost strength and size gains.

HMB is a metabolite of the essential amino acid L-leucine. During many studies on protein effects, L-leucine seemed to be the single greatest contributor to muscle protein synthesis. A recent study examined the effects of an essential amino acid based product, Muscle Armor (MA); manufactured by Abbott Laboratories contains beta-hydroxy beta-methylbutyrate (HMB).

Seventeen healthy men were randomly assigned to one of two groups and performed twelve weeks of periodized heavy resistance training while supplementing with either MA or an isocaloric, isonitrogenous placebo (Control group (CG)). Every two weeks the subject?s strength and power were measured and blood was drawn. More-over the blood draws taken were performed pre, mid and post-training. Researchers found the MA group affected training induced changes in muscular size and strength to a significantly greater extent than the CG. Also found, was reduced levels of circulating muscle damage markers creatine kinase and malondealdehyde compared with the CG. In addition, the MA group experienced increases in resting and exercise-induced testosterone and resting growth hormone levels with reduced pre-exercise cortisol levels.
(Medicine & Science in Sports & Exercise. 2009;41(5):1111-1121)