The fundamental principles of science appear to have been adopted in the domain of strength and conditioning (S&C). For example, when you put the following search terms in PubMed and search by decade, (strength OR resistance OR weight) AND (training OR exercise), it becomes apparent that an overwhelming amount of scientific progress has been made in the last 10 years.
Figure 1. The number of S&C publications by decade using the search string: (strength OR resistance OR weight) AND (training OR exercise), and limited by decade.
For your information, the first reference is: Brunton TL, Tunnicliffe FW. (1897). Remarks on the Effect of Resistance Exercise upon the Circulation in Man, Local and General Br Med J. 2(1920):1073-5. No abstract available.
Further, if citation is a measure of the quality, one might propose that both the quantity and quality of research is growing. For example, the journal of strength and conditioning research increased its impact factor by 88% since 2009, to 1.5, and the Journal of athletic training increased its impact factor by 30%, up to 2.5 in the same time (Hopkins, 2010).
It seems that scientific knowledge in the domain of S&C is growing at an exponential rate. The role of the S&C practitioner is developing a sufficient understanding of first principles, so they are able to translate the latest scientific knowledge into innovative, practical applications. Stay tuned-in to The MMA Training Bible to get the latest research-based training advice on the web.
Hopkins WG. (2010). Impact factors for journals in sport and exercise science and medicine for 2010. Sportscience. 14:60-62.