Sung W, Hicks GE, Ebaugh D, et al. - Through a laboratory case-control design of individuals who were 10 with and 10 without low back pain (LBP), researchers compared and contrasted the pain and stiffness variations between prone instability testing positions and muscle activation patterns during the prone instability test leg raise. In all individuals, spinal stiffness progressed across testing positions. During the test individuals with LBP felt a decrease in pain. In spinal stiffness during leg raising in the test, no between-group variation was determined. During the leg raise, individuals without LBP used 3 muscle synergies whereas individuals with LBP used 2 muscle synergies. Therefore, in all individuals, spinal stiffness progressed, but individuals without LBP exhibited a muscle synergy pattern where each synergy was correlated with a distinct function of the prone instability test. Moreover, individuals with LBP used a more global stabilization pattern which may indicate a maladaptive method of enhancing spinal stability.