The immediate and 1-week effects of mid-thoracic thrust manipulation on lower extremity passive range of motion

Research suggests that spinal manipulation may effect motion. Less clear is whether this effect is limited to localized responses or may involve generalizable changes. Objective: To determine whether Mid-thoracic manipulation (MTM) would result in a significant change in the lower extremity passive straight leg raise (PSLR) range of motion immediately and after 1 week. Methods: Twenty-three healthy subjects were randomly assigned in a double-blinded study. An experimental group received MTM and a control group received a sham intervention. PSLR measurements were taken prior to, immediately after, and one week after the intervention. Results: Mixed model repeated measure analysis of variance was used to determine that there was a significant interaction between MTM and time (F(2, 21) = 3.84, p < 0.05). Post hoc tests revealed a significant difference between the pretest to immediate posttest values (p < 0.05, SE = 1.47). PSLR in the MTM group increased 10.3° while the sham group increased 1.9°. Difference was non-significant between pretest and 1-week follow-up (p = 0.129, SE = 2.46). Conclusions: MTM may immediately increase lower extremity passive range of motion, but the effect was lost by the 1-week follow-up. This supports evolving research suggesting that spinal manipulation may have a generalized but transient physiological effect.