Muscle Growth Without Working Out!

Title: Bodybuilding Without Power Training: Endogenously Regulated Pectoral Muscle Hypertrophy in Confined Shorebirds.

Researchers: Dietz MW, Piersma T, Dekinga A.

Institution: Centre for Ecological and Evolutionary Studies, Zoological Laboratory, University of Groningen. The Netherlands and Netherlands Institute for Sea Research (NIOZ)

Reference: Journal of Experimental Biology. 1999 Oct; 202 (Pt 20):2831-7.

Summary: Shorebirds such as Red Knots (Calidris canutus) routinely make migratory flights of 3000 km or more. Previous studies on this species, based on compositional analyses, suggest extensive pectoral muscle hypertrophy in addition to fat storage before take-off. Such hypertrophy could be due to power training and/or be effected by an endogenous circannual rhythm.

Methods: Red Knots of two subspecies with contrasting migration patterns were placed in a climate-controlled aviary (12 h:12 h L:D photoperiod) where exercise was limited. Using ultrasonography, we measured pectoral muscle size as the birds stored fat in preparation for migration.

Results: At capture, there were no differences in body mass and pectoral muscle mass between the two subspecies. As they prepared for southward and northward migration, respectively, the tropically wintering subspecies (C. c. canutus) gained 31g and the temperate wintering subspecies (C. c. islandica) gained 41g. During this time, pectoral mass increased by 43-44 % of initial mass, representing 39% (C. c. canutus) and 29% (C. c. islandica) of the increase in body mass. The gizzard showed atrophy in conjunction with a diet change from molluscs to food pellets.

Conclusion: Although we cannot exclude the possibility that the birds' limited movement may still be a prerequisite for pectoral muscle hypertrophy, extensive power training is certainly not a requirement. Muscle hypertrophy in the absence of photoperiod cues suggests the involvement of an endogenous circannual process.

Discussion: Some of you may be thinking, "What do we care about shore birds?" Well, admittedly, if you are not a bird watcher, which I am not, we don't really care about shore birds. But these shore birds are no ordinary shore birds! The pecs on these guys actually grow once a year without any kind of exercise. Now that is interesting...

Essentially what these researchers found was that these birds have a circadian rhythm of sorts that acts on a yearly cycle, causing significant muscle growth every year, right on schedule. This is just one more amazing physiological adaptation involving muscle growth we find in nature, but not in humans. Another nifty adaptation we find is in bears that hibernate. They are able to go a few months without food and yet not lose any muscle mass. Their bodies, with the help of willing kidneys, are able to recycle amino acids so that no muscle mass is lost despite not eating any food at all.

Of course these two examples have little to do with what I or you are going to do in the gym today, but it does expand the mind to the possibilities of the future...a little genetic tinkering and presto! Muscles that grow on their own just in time for summer, and at the same time are entirely immune from the ravages of dieting. Not a bad future wouldn't you say?

Reference: http://www.hypertrophy-specific.com/HSreport/iss07