In vivo research studies

The Basic Rep

Each repetition of an exercise consist of two motions. The eccentric (lowering or un-contracting) and the concentric (raising or contracting). Studies have shown that performed individually concentric training yields a greater gain in muscle size, soreness, and creatine kinase activities. Eccentric training yields greater range of motion, and maximum isolation strength. The amount of tissue damage is significantly greater during the eccentric portion of the rep. Taken together in the proper ratio of emphasis using tempo lifts such as a 2 sec contraction and a 1 second eccentric motion for example can provide optimal increase in muscle size and strength. It is important to note that while the eccentric training may not yield immediate gains in mass, the damage induced repair will lead to increased muscle cell nuclei giving it a higher potential for further growth. This is because the stretch and stress will increase MGF and IGF-IEa in the muscles worked. So the importance of the negative portion of a rep can not be underestimated.

How Many Sets?

Studies show that when comparing a single max effort set of 10 reps after warm up compared to that of a set of 6 reps yielded very different results. Androgen receptors were up-regulated greater in the single set group, in fact there was a 46% drop in androgen receptor content at 1 hour post exercise in the 6 rep group. However the 6 rep group showed a 12-23% increase in testosterone levels post exercise. Thus further research has shown that between these extremes in the 2-3 rep range with proper intensity you can up-regulate both testosterone levels and the androgen receptors with less muscle damage creating a much more anabolic environment. In addition to testosterone studies have shown that when comparing 2 vs 4 sets of an exercise, the 4 sets resulting in increased cortisol levels and HGH levels after muscle hypertrophy (1-RM), 3-min rest) and MH (10 reps at 75% of 1-RM, 2-min rest) and strength endurance training(15 reps at 60% of 1-RM, 1-min rest). There were no differences between muscular strength or testosterone levels between these two groups. Further research would suggest that because of the time length and repeated isolation of the same muscles only cortisol levels began to increase accordingly. By reducing either the time frame or number of sets the HGH./cortisol level may have been more favorable. Spending 12-18 minutes on one exercise is not a good idea. GTP utilizes a method of reps and sets to achieve the HGH stimulation without causing a cortisol increase as seen here. In addition one must consider the effects of exercise induced damage in high set workouts. It does not take a lot to achieve enough muscle damage to signal repair. Research shows that a few skeletal muscle adaptation can be brought about by a single bout of relatively few eccentric muscle contractions. Increasing the number of eccentric muscle repetitions did not result in an increased prophylactic effect on skeletal muscle. Furthermore adaptation to eccentric exercise can occur in the absence of significant muscle damage. Exposure to a small number of non-damaging eccentric contractions can significantly improve recovery after a subsequent damaging eccentric bout. However this adaptation appears to be mode-specific and not applicable to concentric contractions.
In conclusion the cellular response for growth from muscle damage is directly related to creatine kinase levels which do not increase with further muscle damage by repeated eccentric sets.

How often/ training frequency

Training frequency has been discussed among athletes for quite some time. Research shows that while everyday training actually increases anti-hypertrophy factors and increase in myostatin levels, 48 hours in between sessions provides a steady anabolic environment. Serum testosterone levels, the free androgen index, Androgen receptor mRNA and protein were significantly increased. No negative factors were found to be increased in this study. With more than 48 hours between exercise sessions these levels begin to decline fast. This study used 3 sets of the exercise, and took data after 3 sessions each 48 hours apart.