Muscle Strength Versus Muscle Size

A bigger muscle isn’t necessarily a stronger muscle, as a study from the University of Nebraska-Lincoln suggests. Low-load reps will build muscle size, but you have to go heavy to optimize strength. Findings about the nervous system’s role in strength gains were published in the journal Frontiers in Physiology.
 
Researchers had 26 male volunteers perform leg extensions 3 times a week for 6 weeks. Some used 30% of their one rep max (1RM) and others used 80% of 1RM. All trained to failure. Muscle growth was similar for both groups, but there were differences in strength gains.
 
Over 3 weeks, voluntary muscle activation increased 0.15% for the low-load group and 2.35% for heavy load lifters. By the end of the program, heavy load lifting helped increase 1RM by about 10 pounds. Researchers think a heavier load makes the nervous system activate more motor neurons compared to low-load training.