MRI scans prove it: developing lower body muscles is more difficult than developing upper body muscles
Most men who have been working out with weight for some time already know what Japanese sports scientist discovered 15 years ago using MRI scans: the muscles in the upper body grow faster than those in the lower body.
The researchers, who were associated with the Tokyo Metropolitan University, had three young men work out with weights for 16 weeks. The subjects trained 3 times a week, and then did work with 5 basal exercises - the squat, leg-extension, leg-curl, bench press and lat-pulldown - the most important muscle groups of the body. The subjects did three sets of each exercise, and trained with a load with which 8-12 reps were possible.
Before and after the 16 weeks training period, the researchers determined the body composition of the men using MRI.
After the training period the men were 2.3 kilos heavier, but according to the MRI scans the men won no less than 4.2 kilos of muscle mass.
If strength training newbies want to know how many muscles they have gained recently, they obviously can not rely on the good old scale. It underestimates the number of kilos of freshly acquired muscle mass.
The MRI also indicated which muscles had grown considerably, and which less. The greatest growth had occurred in the muscles of the upper body. The large muscles in the lower body - the glutes and the quads - came in second place. That is remarkable, because 3 of the 5 exercises that the men had done, stimulated the muscles of the lower body.
"If changes in muscle hypertrophy were constant across every muscle, then a single anatomical cross sectional area would reflect changes in skeletal muscle mass", the researchers wrote. "However, our data show that muscle hypertrophy did not occur uniformly throughout each individual muscle or region - for example, trunk, arm, and leg - of the body."
Br J Sports Med. 2003 Dec;37(6):543-5.
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