We can't begin to test the biological impact of IS training without a definition of what IS training is. We don't need to conduct tests to know before hand that nothing in IS will allow people to change beyond their genetic limits. In science people make baseline assumptions given a range of things that are already known. In order to transform the genetic boundaries IS would have to change the genes. That's very testable.
If you are going to invoke genetics...
There is an entire area of biochemistry/molecular biology called "epigenetics" that focuses on the chemical modifications that can be made in DNA - many of them linked to environmental factors. The following comes from an editorial overview of a special section on epigenetics in the journal Nature, one of the most highly regarded science journals in the world:
"Epigenetics is typically defined as the studyof heritable changes in gene expression that are not due to changes in DNA sequence. Diverse biological properties can be affected by epigenetic mechanisms: for example, the morphology of flowers and eye colour in fruitflies.
Epigenetic changes are crucial for the development and differentiation of the various cell types in an
organism, as well as for normal cellular processes such as X-chromosome inactivation in female
mammals and silencing of mating-type loci in yeast. However, epigenetic states can become disrupted by environmental influences or during ageing, and the importance of epigenetic changes in the development of cancer and other diseases is increasingly being appreciated."
Also see Bird's article "Perceptions of epigenetics" in the 5/24/07 issue of Nature (page 396). Based on what I know at this point, can I rule out that IS training may result in epigenetic modifications within cells? No. Can I say that IS training definitely results in epigenetic modifications? No. It remains an open question...one that could be testable, assuming we knew where in the human genome to look for these possible epigenetic modifications.
But I'm beginning to think that there is the start of one heck of a grant proposal in the above sentences…