Muscle building scientific research, or the science of 'muscle hypertrophy' doesn't hold too many secrets. If anyone is telling you something different then they are trying to sell you something. Okay, you can fine tune your approach for sure, but the basics are well known.
It's work, work and more work for the muscles in conjunction with eating sufficiently to fuel the extra growth that you stimulate. Even so, a new paper in the Journal of Strength and Conditioning Research by Brad Schoenfeld, author of the Women's Home Workout Bible (that I reviewed recently), takes us through what is known about the finer points and practices of muscle building. Here is a summary of what he found:
- Two types of muscle building - hypertrophy (increased size of fiber components) and hyperplasia (increased numbers of fibers); also sarcoplasmic hypertrophy may include fluid (the pump)
- Important hormones - testosterone, insulin-like growth factor, human growth hormone - stimulated by training
- Conditions for muscle growth - tension, muscle damage, metabolic stress (lactate etc)
- Training variables - intensity (load), volume (total sets x load),
- Exercise selection - compound exercises as a base, supplement with isolation exercises
- Rest interval - around one minute
- Speed of movement - medium to fast, but not superslow
Author's Summary: "A hypertrophy-oriented program should employ a repetition range of 6-12 reps per set with rest intervals of 60-90 seconds between sets. Exercises should be varied in a multiplanar, multiangled fashion to ensure maximal stimulation of all muscle fibers. Multiple sets should be employed in the context of a split training routine to heighten the anabolic milieu. At least some of the sets should be carried out to the point of concentric muscular failure, perhaps alternating microcycles of sets to failure with those not performed to failure to minimize the potential for overtraining. Concentric repetitions should be performed at fast to moderate speeds (1-3 seconds) while eccentric repetitions should be performed at slightly slower speeds (2-4 seconds). Training should be periodized so that the hypertrophy phase culminates in a brief period of higher-volume overreaching followed by a taper to allow for optimal supercompensation of muscle tissue."
Schoenfeld BJ. The mechanisms of muscle hypertrophy and their application to resistance training. J Strength Cond Res. 2010 Oct;24(10):2857-72.