By Raymond Shipley
Just about every personal trainer I have overheard, or come into contact with, throughout my nearly 20 years in fitness has been very one dimensional in their approach. The trend seems to center around training clients using textbook techniques and exercises, without ever deviating into training styles that have been proven effective by myriad bodybuilders throughout the history of the sport.
Partial reps, or the act of doing an exercise through a shorter range of motion (ROM) than normal, has been ostracized by newly certified and part time, after school trainers since I can remember. The book says don't do it, so that's that (despite their often having used it themselves). But, does such a technique work to promote strength and muscle growth?
The short answer is, yes. Bodybuilders since the beginning of recorded bodybuilding have used the technique to varying degrees of success. The research corroborates these observations. University of Southern Mississippi at Hattiesburg scientists had 56 male subjects follow a 10-week strength training program that included three sets of bench press completed twice per week. One group trained using full ROM using 65% of their 1RM (one rep max), while the other used a partial ROM, about 2-5 inches short of elbow lockout, with about 100% of their 1RM. After the 10 weeks, both groups had increased their full-ROM bench press by about 25 pounds.
This study suggests using partial ROM can and does have its place in bodybuilding and fitness. If one has an injury, doing full ROM repetitions may not be possible, and thus a partial ROM should not be shunned as ineffective. Using a partial ROM with heavier weights than one can comfortably complete full ROM reps also has the psychological benefit of overcoming preconceived barriers in weight and repetitions. Moreover, the research suggests that a combination of partial rep training with full ROM training can yield greater strength gains than using a single method.
There is, of course, an obvious caveat, and that is keeping a healthy active range of motion (AROM). Overuse of partial reps, or underuse of full ROM, can result in a limited AROM. The quick solve is to use partial ROM sparingly and with reason. Train not only hard, but smart.