A: Yes, X Reps are better because you extend the set at only the precise point in the exercise’s stroke that is key for force production and/or fiber activation. With forced reps, on the other hand, you writhe around as you strain through full range reps with help from your training partner. So while X Reps help you circumvent nervous system failure for an extra hypertrophic surge, forced reps waste a lot of nervous energy as you push through weak areas of the stroke with imprecise unloading (pushing or pulling from your partner). That’s why trainees who use a lot of forced reps tend to get tremors after training—they overstress the nervous system.

A recent study appears to confirm that (International Journal of Sports Medicine, 24:410-418. [2003]). It featured 15 male athletes engaged in either a maximum-reps routine or a forced-reps routine. Both types of training led to considerable increases in serum testosterone, free testosterone, cortisol and growth hormone; however, cortisol, which is a stress hormone that can cannibalize muscle tissue, was higher in the forced-reps group. Forced reps also produced a greater decrease in maximum muscular force, according to the researchers.

The greater loss of muscle power indicates that forced reps overstress the nervous system and the excess cortisol produces catabolism in muscle. In fact, many studies indicate that the biggest cause of overtraining is nervous system stress, and therefore forced reps do a lot to increase that probability—much more than X Reps. In other words, cue to X Reps short stroke, as opposed to full-stroke forced reps, we believe X-Rep training is a superior way to extend a set for a maximum growth response with less recovery and nervous system stress (Journal of Applied Physiology, 85:2352-2359. [1998]).