|Is myostatin relevant for mass monsters only, or for normal trainees, as well ?|
I am not sure, but a recent study from the University of Padova provides further evidence that the muscle hypertrophy break myostatin may in fact be what keeps you from making the same gains you saw, when you first hit the weights (Paoli. 2015).
In said study, Antonio Paoli et al. recruited 18 male volunteers, human movement science undergraduate students (age = 24.9 +/- 5.3 years), who responded to an invitation to participate in the study. The respondents provided written informed consent to participate in the study and were screened for the presence of diseases or conditions that would place them at risk for adverse responses to exercise.
|Figure 1: Scheme of experimental design. HP, high protein; NP, normal protein; RT, resistance training (Paoli. 2015)|
"The exercises used throughout the program were bench press, latissimus pulldowns, seated rows, shoulder press, biceps hammer curls, and dumbbell lying external rotation. During the first week of training, subjects performed 2 sets of 9–11 repetitions at 75–80% 1RM with 2-min breaks between each set in all exercises except for hammer curl (1.5 min) and dumbbell lying external rotation (1 min). Thereafter, from second to fourth week, the training volume was elevated to three sets.
The IGF-1 Promoting, Myostatin Reducing, Muscle Building Effects of PGC-1 α-4: What It Does and Why Doing Cardio Before Weights Appears to Promote It's Expression | read more.
At the fifth week the intensity of training was elevated to 80–85% 1RM with three sets of six to eight repetitions. The recovery between each set was 3 min for all exercises except for hammer curl (2 min) and dumbbell lying external rotation (1.5 min).
From sixth to eighth week the training volume was elevated to four sets. The participants were instructed to perform the repetitions rapidly (1 sec) during the concentric phase and then return the load through the eccentric (lowering) phase at a more slow and controlled speed (1.5/2 sec). The load was adjusted every week according to the actual number." (Paoli. 2015).In addition to being assigned to identical training protocols, the subjects were randomly assigned to consume either a high or normal protein diet. The participants were put on a fixed-menu plan with either a high (HP) or normal protein (NP) distributed across 5 meals per day. The individual daily caloric need was calculated referring to body composition and adjusted for daily activity. NP and HP diets are isocaloric regarding daily energy needs of subjects while the surplus of calories given by protein supplements were substituted by carbohydrates in diet. Thus
- the subjects in the NP group consumed 0.85 g/kg of body weight protein, while
- the subjects in the HP group consumed 1.8 g/kg of body weight.
|Figure 2: Changes in body composition in the high and low protein group (Paoli. 2015).|
|Figure 3: Myostatin increases more in the HP group and it increases hand in hand with IGF-1 (small figure | Paoli. 2015).|
- Laurentino, Gilberto Candido, et al. "Strength training with blood flow restriction diminishes myostatin gene expression." Med Sci Sports Exerc 44.3 (2012): 406-412.
- Paoli, Antonio, et al. "Protein Supplementation Increases Postexercise Plasma Myostatin Concentration After 8 Weeks of Resistance Training in Young Physically Active Subjects." Journal of medicinal food 18.1 (2015): 137-143.
- Qaisar, Rizwan, et al. "Is functional hypertrophy and specific force coupled with the addition of myonuclei at the single muscle fiber level?." The FASEB Journal 26.3 (2012): 1077-1085.