Build Muscle With Light Weights

Many fitness experts maintain that exercisers must work within the 8 to 12 repetition range to initiate muscle hypertrophy. However, recent studies suggests that low-load, high-volume strength training can also impact muscle growth.

Researchers from McMaster University in Hamilton, Ontario, studied 15 men as they performed four sets of unilateral leg extensions at 90% 1-RM and 30% 1-RM. The subjects were instructed to work until failure. The study authors reported that at 90% 1-RM, subjects usually managed 5–10 repetitions before failure; at 30% 1-RM, failure set in at about 24 repetitions. 

To control nutrition intake, on the intervention date the participants were each given a liquid meal made up of 61% carbohydrate, 15% protein and 24% fat. The researchers then analyzed protein muscle synthesis of the subjects for 24 hours postintervention.

“We report for the first time that low-load high volume resistance exercise is more effective at increasing muscle protein synthesis than high-load low volume resistance exercise,” stated the study authors. The authors also stated that the 90% 1-RM showed increased protein synthesis up to 4 hours postexercise; however, 30% 1-RM showed elevated protein synthesis up to 24 hours postexercise. The ultimate goal, added the authors, is to work until muscular fatigue.

Somehow this theory of more reps is for definition and less reps for mass fallacy became promoted throughout many gyms and weight rooms. In reality, because muscle mass gains have more to do with the overall amount of work done, the individual performing more reps has more of a chance of gaining mass.

For those that would like to argue otherwise, yes, you can find those that become more "defined" (an inaccurate term for body fat loss) through higher reps because they burn a lot of calories. If they also keep the loads low enough they won't have a great ability to do anything than build some low forms of strength. The higher repetitions do work on strength-endurance, but I find there to be a more effective way of building strength-endurance and that is by incorporating many sets of low reps with short rest intervals. This way you maintain higher power outputs and still maintain strength-endurance capabilities.

Lower repetition ranges (usually 1-5) are more for building maximal strength and power. This is dependent upon the loads used by the individual. The reason that many will not see great size gains by using these repetition ranges is because they usually do not allow one to obtain the same volume of work, which is a key we already determined to adding size. However, there are some that will put on some size and many will put on a little of what we call functional muscle mass from using these repetition ranges. Functional in the fact that your gain in muscle size will correspond positively with strength gains.

The low rep brackets and ranges should be used by all people, but the amount of time spent with these different rep/set schemes is again dependent upon one's goals.