>Rob posted an article- >NASA has a special interest in isometric exercises--i.e., non-moving >exercises where an astronaut pushes hard against a fixed surface. >Motionless exercises allow for simple lightweight equipment less >expensive to launch and less prone to break during a mission. But are >they effective?
Just a few comments on this article... nothing that is "new", but basic concepts learned as part of training in muscles and function in school a "while ago"..... Isometric exercises have been shown to be effective... within the limited range of the work out. To put it in lay terms- if I hold my elbow bent to a 90 degree angle and do an isometric contraction, the strengthening is limited to the 90 degree range (+/- 10-15 degrees). In concept we use this in rehab where joint loading is not desired through the motion. The limitation is that you must work through a wide number of points in the range to accomplish "strengthening through the full functional range" and this does not account for "timing and motor learning". >To find out, Baldwin's group gave laboratory rats a workout by >activating the rodents' leg muscles with painless electrical >stimulation. They tested three types of exercise: muscle contraction, >muscle lengthening, and isometric, where the muscle exerts a force >while remaining the same length. (Just think of doing push-ups: muscle >contraction occurs in the "up" part of a push-up, muscle lengthening >during the "down" part, and isometric while holding a push-up midway.) Studies in electrical stim have largely not been maximal contractions since even 2/3 max tends to be very uncomfortable. The research in "Russian Stim" included some incredible things that just didn't pan out as originally thought. (Recall the days of "gyms" in the 80's where people laid on a table and the electrodes were placed on their muscles and they got a "workout while relaxing"?) There may have been some advances in this technology in some of the spinal cord rehab centers, but largely this was probably feasible with the lowered sensation of the tissue and there have been problems with tissue integrity. By looking at the link it appears they may have done this in space which I have not read details on. If the muscle is getting "no workout" it may tone a bit, but largely doesn't "strengthen" >After the sessions, the scientists performed tests to see how the >rats' muscles responded. "What we found," says Baldwin, "was that >after 12 sessions, all three types of workout tended to provide about >the same amount of muscle growth," even the isometric exercises that >involved no motion. > (snip hormones, growth factors, etc... not sure how this might relate to steroid related things, but Debbie might) >"Some people think that it's the mechanical stress that turns the gene >(for IGF-1) on, but we really don't understand that process yet. What >we do know is that IGF-1 triggers muscle growth," Baldwin explains. > >Might supplements of IGF-1 be used to ensure that construction of >muscle proteins keeps pace with protein destruction in astronauts? >Baldwin says they're entertaining the idea and are already discussing >ways in which that might be done. > >If they're successful, it will be good news for more than just >astronauts. After all, we're all owners of that incredible, >self-adapting machine called the human body. One of the places that isometrics (same length), isotonics (same tension) and isokinetics (same speed) have fallen short are in regards to functional movements- much "weight/workout" equipment is "free limb" (the body is stationary and the limbs move). In RL the lower limbs tend to work more "stable" and the trunk moves over/ around/in relation. The motions for "workouts" also tend to be uniplanar which isn't how bodies generally function. The past15 years have seen movment in more functional rehab without machines in lieu of the equipment that can replicate function (overly simplistic). Some of this probably relates to the "loading/unloading" discussed in Dr Baldwin's profile, PTs generally relate loading to ..... the effects of gravity on the body :-) Enough on muscles and such unless you want more info, Dee _______________________________________________ http://www.mccmedia.com/mailman/listinfo/brin-l
