Here is a post I made on another forum. It will give some back to long duration ISOs for hypertrophy.
Okay, I’ve been doing a lot of digging and I’ve finally found scientific documentation that supports the use of long duration unloaded ISOs as used by Jay Schroeder.
JackM, the brilliant contributor over on the DB Boards, has said numerous times that failure in long duration ISOs is due to occlusion, and that loads light enough to be held for extended periods of time would cause fiber transformation towards type I fibers. However, I’ve discovered studies dealing with a new type of Japanese training known as “Kaatsu” that demonstrate the exact opposite.
Kaatsu training involves lifting loads of roughly 20% 1RM for 15-30 reps while one has a tourniquet fastened over the proximal part of the limb they’re working. The tourniquet limits oxygen transport to the muscles and deprives the type I fibers of the fuel they need to contract. Within this environment, type II fibers thrive and have been shown to increase in volume by 27.6% after only 2 weeks of training. Similarly, whole muscle cross sectional area has been shown to increase by upwards of 5% for highly trained college T&F;athletes within the same time frame, while increasing strength by nearly 10%.
This is believed to happen because IGF-1 and GH levels skyrocket after performing Kaatsu training. Also, the body learns to produce more fast twitch fiber when confronted with a lack of oxygen.
Jay’s several minute long ISOs would work much the same as Kaatsu training, but instead of a tourniquet cutting off blood flow (and therefore oxygen) to the working muscles, the sustained contraction will do the job. Not only will the ISOs work to elongate the local fascia, but they will also provide functional type II fiber hypertrophy, and in large amounts too. In fact, James once claimed to have gained 16 lbs in one month from the use of light ISOs alone. This claim was scoffed at on the CF Forums, but it’s completely believable under the training conditions.
The only real downside to this type of training is that while absolute strength does increase, relative strength does not. It appears that Kaatsu, or any hypoxic training, does not affect the nervous system. This can be corrected by implementing normal training simultaneously though, or at least I believe it can.
Here are some links to relevant Kaatsu training articles:
One can also get results by going to http://www.scholar.google.com and searching for Kaatsu.
As for the other points, it increases ROM because it is basically an eccectric quasi-isometric. And since flexibility and ROM are mostly neurological, spending a long time in the extreme end of one’s ROM will provide a great opportunity for the muscles to learn their new resting length.
And it increases mitochondrial mass and glycolytic enzymes because it is a form of hypoxic training, which has been shown to have these two effects in previous studies.
Sorry for being so vague, but my research is scattered all over the place and this is the best I could do on short notice.