“A successful backward step correlates with hip flexion moment of supporting limb in elderly people,” by Yahiko Takeuchi (PLoS ONE 13(1): e0190797. doi.org/10.1371/journal.pone.0190797, XML, HTML, and .pdf format, 9p.).
journals.plos.org/plosone/article?id=10.1371%2Fjournal.pone.0190797
