[QUOTE=canyonoak;4656165]
http://www.animalsandsociety.org/assets/library/114_jaws09015.pdf
these are all in peer-reviewed publications[/QUOTE]
I think the paper is interesting, but limited - and to be fair the author does acknowledge certain limitations of the study. As far as I can tell, the methods are fine. However, I would like to have seen heart-rate measurements done during the training session to see whether there were any significant changes going into and out of RK. Even without using new techniques for factoring out the contribution of exercise to heart rate, a comparison between RK and non-RK periods could have been done if the overall level of exercise was the same for both. As has been pointed out already, the difference in HRV after the session could be due entirely to the difference in training regime - it could have nothing to do with RK. So I think the author’s conclusion is unjustified. Still, she does argue for further work to be done, which I agree with.
Journal of Applied Animal Welfare Science is indeed a peer-reviewed journal, though not in quite the same way as it is for most science journals (at least, not any journal I have submitted to or reviewed for). In the case of JAAWS, manuscripts are reviewed by a limited board of editors, rather than being sent to other scientists working in the same or closely related field. It isn’t clear how many of those editors would be familiar with the subject being studied here. That wouldn’t stop them doing a reasonable of reviewing the paper, but it might not be as incisive as one from someone who has worked with horses and/or done HRV measurements themself.
I don’t mean to damn the article - I think it is a useful addition to the literature. One just has to be careful not to assign it too much weight by itself.