Let me run through the fiber types our muscles possess and the characteristics of each. This should clear up any confusion about why Max-OT is the most effective training method for packing on lean mass in the shortest possible amount of time.
Muscle fiber types fall into three main categories; slow-twitch (type-I), glycolytic fast-twitch (type-IIx) or oxidative fast-twitch (type-IIa). Slow-twitch fibers are recruited to lift lighter loads and have a substantial endurance capacity. Slow-twitch fibers also have very little capacity for increasing size. Type-IIa and IIx fibers are characterized as fast twitch, these fibers produce the highest levels of force and are recruited only during the heavier sets in weight lifting. Fast-twitch fibers, not slow-twitch muscle are capable of dramatic growth responses from training. Particularly the type-IIx fast-twitch fibers possess the greatest capacity to produce force and size increases. Whereas the fast-twitch type-IIa fibers can be thought of as “intermediate fibers”, they cover the middle ground and bridge the gap between the slow-twitch and high threshold type-IIx fast-twitch.
When lifting an object, be it a pencil or a 150 pound dumbbell, muscle fibers are recruited in the exact same order. That is, from slow-twitch for lighter objects, right through to the type-IIx fast-twitch for very heavy weight lifting. The number and type of muscle fibers recruited is always determined by the amount of weight (overload) used.
Lifting light loads for a high number of reps only serves to recruit the slow-twitch fibers, no matter how many reps are performed. Unless a bodybuilder utilizes heavy weight they don’t even begin to tap into the fast-twitch type-IIx muscle fibers. Remember these are the fibers that are responsible for dramatic growth changes, and large gains in muscle mass. Slow twitch fibers have very little capacity for increasing size.
When an athlete chooses to utilize the 4-6 maximal repetition range during training, they have automatically “locked” themselves into working with very heavy weight that enables high overload to be placed on muscle. Remember, attempting to lift heavy weight is the only way to recruit the fast-twitch type-IIx muscle fibers. In terms of stimulating muscle growth, working with anything lighter than this is wasting time and effort.
Most people on this planet possess a small number of type-1, and type IIx fibers, and a majority of type-IIa fibers. For most of us, the reality is that the proportion differences between people are miniscule unless they are in the elite class of their chosen sport. Also, unless you have a muscle biopsy taken from every single muscle group in your body, a person can never be absolutely sure of the proportion of fiber types they possess in each muscle, and, this proportion can differ from muscle group to muscle group.
Aside from genetics, muscle growth rates between individuals are heavily influenced by a multitude of other factors such as; nutritional intake, the type of training performed and training history. From the research, it appears that the type of training a person performs can alter the proportions of these fiber types. This means, a bodybuilder that’s been training the Max-OT way for a number of years will have muscle fibers that are more suited to fast-twitch, high threshold contractions – a highly desirable benefit for future gains.
The bottom line is this, an athlete that desires substantial increase in lean body mass must lift heavy weight that can be handled for 4-6 repetitions maximum. Once this rep range is surpassed, more weight needs to be added. The 4-6 rep range enables maximal overload to be placed on muscle and therefore recruits the fast-twitch muscle fibers that respond the most dramatically to resistance training.