Monday, June 6, 2011

Chicken Legs No More! Building Big Wheels By Walking on the Treadmill: Blood Flow-Restriction Does the Trick!

Image 1:  One thing is certain, the squat, the
"King of all Exercises" will never become obsolete.
(image by verkinetic @Wikipedia)
You have chicken legs, but are too lazy to squat? Well, I guess in this case you will be interested in the results of a recent study by Sakamaki et al. (Sakamaki. 2011) who found that blood flow-restriction is all it takes to induce legs and trunk muscle hypertrophy by just walking the treadmill.

For their study, which was published in the latest issue of the Journal of Sports Science and Medicine the Mikako Sakamaki from the University of Tokyo and his colleagues from the University of Oklahama had 17 "healthy young" men [21.2 (±1.9) years, 1.74 (±0.07) m, and 65.8 (±9.6) kg] participate in 3 weeks of supervised walk training. Following a warm-up, the subjects performedwalking (50 m/minute for five 2-minute bouts, with a 1-minute rest between bouts) on a motor-driven treadmill. The walking speed and duration remained constant throughout the training period.
Figure 1: Relative changes in muscle volume over a 3 weeks training period in blood flow-restricted and control group; note: Only the changes in thigh and lower leg musculature were statistically significant 
(data adapted from Sakamaki. 2011)
Now, 9 randomly selected subjects wore a elastic cuffs that were inflated with a pressure of 160 -230 mmHg during the training sessions (BFR-group). Before and after the 3 week training period muscle cross-sectional areas (CSA) were assessed by magnetic resonance imaging (MRI) and revealed that
[...] MRI-measured upper (3.8%, P < 0.05) and lower leg (3.2%, P < 0.05) muscle volume increased significantly [in the BFR group only!] 
Size and volume of the "gluteus maximus (-0.6%) and iliopsoas (1.8%), [as well] as the muscle CSA of the lumber L4-L5 (-1.0) did not change", however. A result that could be expected, considering the position of the cuffs which restricted blood flow to the lower extremities, while muscles from the gluteus upwards were still well perfused.

Bottom line: For trunk size wheels you probably won't get around doing squats or heavy leg presses to build appropriate strength; but imagine what may happen if you do these in a high volume "Kaatsu style", i.e. with cuffs to restrict blood flow... Jay Cutler, beware!