20（）

A.renewing
B.recovering
C.healing
D.curing

Current gym dogma holds that to build muscle size you need to lift heavy weights. (1) , a new study (2) at Mc University has shown that a similar degree of muscle building can be achieved by using lighter weights. The secret is to pump air (3) you reach muscle fatigue.

The (4) are published in PLoS ONE.

" (5) grunting and straining to lift heavy weights, you can (6) something much lighter but you have to lift it until you can’t lift it (7) ," says Stuart Phillips, associate professor of kinesiology at Mc University. "We’re convinced that (8) muscle means (9) your muscle to make new muscle proteins, a process in the body that over time (10) into bigger muscles. "

Phillips praised lead author and senior Ph.D. student Nicholas Burd for minding the project that showed it’s really not the weight that you lift but the fact that you get muscular fatigue that’s the (11) point in building muscle. The study used light weights that (12) a percentage of what the (13) could lift. The heavier weights were set (14) 90% of a person’s best lift and the light weights at a mere 30%o of what people could lift. "It’s a very light weight," says Phillips noting that the 80% 90% (15) is usually something people can lift from 5～10 times before fatigue sets in. At 30%, Burd reported that subjects could lift that weight at least 24 times (16) they felt fatigue.

"We’re (17) to see where this new paradigm will lead," says Phillips, adding that these new data have (18) significance for gym enthusiasts but more importantly for people with compromised skeletal muscle mass, (19) the elderly, patients with cancer, or those who are (20) from trauma, surgery or even stroke.