Public Release: 

Study says: 'whey' to greater muscle strength is through training and protein supplements

American Physiological Society

April 9, 2003 (San Diego, CA) - Elizabethan England preferred it to milk; Miss Muffett enjoyed it on her tuffet before the spider showed up; now professional, collegiate, amateur, and recreational athletes combine it with creatine to supplement resistance training, with the expectation of improving gains in strength and muscle mass. The "it," of course, is whey.

Whey is a naturally occurring dairy protein found in bovine milk. Whey isolate, the highest quality form of whey that is extracted and purified during the cheese making process is shown in research to possess some extraordinary nutritional properties. In 2001 creatine supplement consumption in the US alone exceeded more than 2.5 thousand metric tons

Researchers at Victoria University in Australia have previously shown that supplementation with creatine or a 100% whey isolate formulation significantly (P<0.05) increased levels of muscle force and mitochondrial energy production in rats as well producing significantly better (P<0.05) improvements in strength and body composition in bodybuilders during resistance training.

Now, these scientists lead by Prof. Mick Carey and Dr Alan Hayes at the Centre for Rehabilitation, Exercise and Sport Science have produced a study that shows supplementation with a100% whey isolate formulation and creatine produced greater muscle fiber growth increases that transferred into significant increases in functional strength.

A New Study

These researchers examined the effects of a whey isolate and creatine supplementation on muscle fiber characteristics and their correlation to changes in strength during resistance training.

Analysis of muscle fibers taken from experienced bodybuilders before and after 11-weeks of resistance training have revealed a significantly (P<0.05) greater increase in the cross sectional area (size) of the fast-twitch muscle fibers in the men supplementing with whey isolate and creatine compared to a group of men consuming an equivalent calorie-containing supplement.

The fast-twitch muscle fibers are responsible for maximal force production and the hypertrophy (growth) response to resistance training. The most interesting finding from this research was that a highly significant (P<0.001) correlation between the magnitude of strength gained in three weight lifting exercises assessed and the increase in size of all fiber types was revealed.

Dietary strategies that enhance the results of resistance training have important implications to athletes, an aging population and others that suffer from debilitating conditions that cause muscle wasting.

A report on the findings of this study, "The Effect of Whey Isolate, Creatine and Resistance Training on Muscle Fiber Characteristics, Strength and Body Composition," will be delivered by researcher Paul Cribb at the "2003 Experimental Biology Meeting," a meeting of co-sponsored by the American Physiological Society (APS). The gathering is being held April 11-15, 2003, at the San Diego Convention Center, San Diego, CA.


In a double-blind protocol thirty-three resistance-trained males were matched for strength and placed into one of four groups: creatine/carbohydrate (CrCHO), whey isolate (W), creatine/whey isolate (CrW) or a carbohydrate-only (CHO). All subjects undertook the same fully supervised resistance training program three times per week and consumed 1.5gms of supplement/kg body wt/day. Strength was assessed by 1-RM in three exercises and body composition assessed by DEXA. Fiber proportions and cross sectional area (CSA) were determined from vastus lateralis muscle biopsy samples. Computer analysis of macronutient intake of all subjects was completed three times during the study; all other assessments occurred in the week before and the week after training.


While all groups demonstrated increases in strength, lean mass and CSA, the CrCHO, W and CrW groups all demonstrated significantly larger gains (P<0.05) in strength and lean mass and greater increases (P<0.05) in type II CSA. Additionally, the CrW group demonstrated a greater increase (P<0.05) in strength, lean mass, and fiber CSA than W. There was also a highly significant (P<0.001) correlation between the magnitude of strength gained and the increase in the cross sectional area of all fiber types. There was no change in fiber type proportions in any of the groups.


Experienced resistance-trained males supplementing with CrCHO, W and CrW achieved greater increases in strength and lean mass following 11-weeks of training compared to a CHO supplement, with changes being enhanced by the combination of creatine and whey compared to whey alone. Supplementation with CrCHO, W and CrW resulted in a greater increase in CSA in all fiber types assessed, and these increases strongly correlated with the strength gains. This research was supported by AST Sports Science.


The American Physiological Society (APS) is one of the world's most prestigious organizations for physiological scientists. These researchers specialize in understanding the processes and functions underlying human health and disease. Founded in 1887 the Bethesda, MD-based Society has more than 10,000 members and publishes 3,800 articles in its 14 peer-reviewed journals each year.

Contact: Donna Krupa @ 703-527-7357 (vm) Or 703-967-2751 (cell) or Through April 10th, 2003.

FRIDAY APRIL 11th, 2003
@ 7:00 AM PST

APS Newsroom: April 11-15, 2003
San Diego Convention Center
Hall A (Flex Unit)
Telephone: 619-525-6340 or 6341

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