Grow Stubborn Muscle Fibers
One of the prevailing theories about resistance training and muscle growth has to do with tapping into stubborn Type II muscle fibers. You generally need to exhaust Type 1 fibers before you can access the Type II fibers, but those Type II fibers often resist your attempt to get at them. Metaphorically, they keep their legs crossed, and conventional sets of 3 x 8 only get you so far.
A group of Brazilian scientists, however, have figured out a way to get those Type II fibers to stop being so shy before you even start your set.
It seems that if, prior to doing your regular work sets, you do just one set to exhaustion using 20% of your 1-rep maximum (1RM), you fatigue the Type 1 fibers enough to open the door to accessing Type II fibers, resulting in greater strength and hypertrophy gains.
Researchers recruited 27 men and split them into three groups:
- A control group that did nothing.
- A group that trained upper legs for 8 weeks by doing 3 sets with 75% of their 1RM, taking one minute of rest between sets.
- A third group that did exactly the same as the second group, only they started the workout by doing 1 set of 20% RM to exhaustion and waiting 30 seconds before starting their traditional sets.
Quite simply, the men who first did the mini-set to exhaustion showed greater gains in strength and muscle size than the group that trained their legs in the traditional way.
The researchers explained that reaching failure of Type 1 muscle fibers would promote a greater recruitment of Type II fibers during traditional sets. They concluded the following:
"...the inclusion of a single set of exhaustive exercise at 20% of 1RM before traditional hypertrophic training can be a suitable strategy for inducing additional beneficial effects on quadriceps strength, hypertrophy, and endurance in young men."
Based on their study, it seems that this preemptive exhaustion set works well for leg extensions, but I can't think of a reason why it wouldn't work for multiple muscle parts. Doing biceps curls today? Try the following:
- Assuming a 100-pound 1RM in the barbell biceps curl (cuz' the math is easier), pull out a 20-pound pre-set barbell, but have a 75-pound bar standing by (because 75 pounds is 75% of a 100-pound 1RM).
- Rep out with the 20-pound barbell, i.e., do as many as you can.
- Rest 30 seconds.
- Start your regular workout of 3 to X number of sets using 75 pounds and resting one-minute between sets.
- And, if the researchers were right, grow like a fiend.
- Aguiar AF et al. A single set of exhaustive exercise before resistance training improves muscular performance in young men. Eur J Appl Physiol. 2015 Jul;115(7):1589-99.