I can't speak to other methodologies, but if you're interested in the lineage and philosophy of Crossfit, the old journal articles by Glassman et al. are a gold

I can't speak to other methodologies, but if you're interested in the lineage and philosophy of Crossfit, the old journal articles by Glassman et al. are a gold mine. https://journal.crossfit.com/article/what-is-fitness https://journal.crossfit.com/article/what-is-fitness <- 2002 piece (with updated pictures) that really sums everything up http://library.crossfit.com/free/pdf/CFJ_2016_05_Pegboard-Warkentin-V6.pdf http://library.crossfit.com/free/pdf/CFJ_2016_05_Pegboard-Wa... <- "Best of" index