 This randomized clinical trial is designed to compare the outcomes of a prescriptively applied non-thrust manipulation to a pragmatically applied non-thrust manipulation on subjects with mechanical low back pain. The study has two primary aims. Specific Aim 1 examines immediate effect differences between a pragmatically applied localized non-thrust manipulation versus a prescriptively applied, non-localized non-thrust manipulation in subjects with mechanical low back pain. Specific Aim 2 examines longer-term differences between a pragmatically applied localized non-thrust manipulation versus a prescriptively applied, non-localized non-thrust manipulation in subjects with mechanical low back pain. The investigators hypothesize there will be no differences between the two applied treatment techniques in immediate and longer-term assessments. 