A: The whole new feel you refer to is the muscle continuing to fire after the nervous system halts full-range movement. That’s what makes X Reps such a powerful muscle-building tool. It’s ultimate intensity and overload. Plus, that muscle burn is one of the best ways to get surges in growth hormone.
In a study published in the Canadian Journal of Applied Physiology (22:244-255; 1997), researchers showed that there’s a direct correlation between higher blood lactic acid levels and GH release from the pituitary gland. That means the more muscle burn you can induce, the more growth hormone you can stimulate—up to a point. And growth hormone does everything from help you build muscle and burn fat to bolster your immune system and strengthen bones, ligaments and tendons. Talk about bodybuilding bonus points!
Because X Reps are so intense, most trainees will get best results by doing one straight set to failure followed by another straight set to failure with X Reps. The first straight set to failure is more of an extension of the warmup. A warm muscle can contract up to 20 percent better than a cold one, so having the muscle primed for your X Rep set is very important. (Most bodybuilders don’t warm up sufficiently, which can significantly limit progress.) The first heavy set to failure extends the warmup sets you do prior to your first work set, and it also pumps up nervous system reaction time so your X set is X-ponentially more effective.
If you have an above-average recovery ability, you may benefit from doing both sets with X Reps; however, if you try it and start feeling lathargic and lose your enthusiasm for training, back off. That’s overtraining trying to step in and stomp on your progress. Don’t let that happen. We recently tried doing a straight set, and then two X-Rep sets, but we felt too drained and backed off to one. The bright side is shorter workouts and better results. X Reps work, but you can’t abuse them.
Bodybuilding bonus: While X Reps force more muscle-fiber activation, they also can trigger growth hormone surges via muscle burn. GH does everything from help you build muscle and burn fat to bolster your immune system and strengthen bones, ligaments and tendons.