There’s been a lot of discussion about the effect of overtraining and resistance exercises and the viewpoints are quite diverse, but it seems we might finally have an answer to this vital bodybuilding question. While Mike Mentzer claims that all bodybuilders are overtraining, there are a number of scientists that deduced with overwhelming results that nobody could ever be overtrained, and they backed this up with a scientific study!
The parameters of this study were strictly controlled, with the subjects going through a standardized diet and working out excessively with heavier loads than normal, as well as shorter recovery times in between sets and muscle activity fluctuations between their anabolic and catabolic states. This study was performed on male rats, and they were assigned to a trained or a sedentary group, after which they were subjected to a program lasting for 12 weeks. During these 12 weeks, they trained with excessive intensity and really short recovery, which was supposed to make their leg muscles atrophy.
The rats were exercises for five days a week consecutively with jumps as their reps. They were trained with a progressive number of sets from 2 to 4, as well as reps, from 5 to 12 per set with 30 seconds of rest between sets. They also wore loaded vests weighing 50% of their bodyweight which provided the overtraining effect.
After 12 weeks of experimenting, researchers gathered the muscle fibers of the rats to analyze the markers of their muscle state, both the anabolic and catabolic ones like MAFbx, MyoD, IGF-I and myogenin expressions. The results showed that the rats who overtrained had a 17 reduction of muscle size in their legs in comparison to the sedentary rats, and there was also a 20% rise in MAFbx protein expression, which is a marker of muscle catabolism. On the other hand, the markers of muscle anabolism like MyoD, myogenin and IGF-I were drastically reduced by 27, 29 and 43 percent respectively.
The data concluded that the muscles atrophied because the rats went through overly strong training without sufficiently recovering between sessions, which caused the MAFbx catabolic protein to rise and all the other anabolic proteins to decrease. If this translates into human terms, and the scientists think it does, it means that you should never overtrain, especially if you’re an athlete. Don’t bump up your weight too much – instead, look for a periodizing and volume-varying program.