Prolonged standing on a sloped surface rather than on a level surface results in decreased subjective low back pain (LBP) and associated biomechanical changes, according to researchers at the Regis University School of Physical Therapy in Denver. Nelson-Wong and Callaghan1 noted that occupations that require prolonged periods of standing have been associated with increased reports of musculoskeletal disorders, including LBP. Therefore, they investigated the subjective and biomechanical responses of persons in whom pain was known to develop and of those in whom it was known not to develop (previously determined during level standing) when they were exposed to the same prolonged standing task protocol completed while standing on a surface sloped +16° or –16°.
Overall LBP scores were reduced by 59.4% in the pain-development group with use of the sloped surface, compared with the non–pain-development group. A marked decrease in coactivation of the bilateral gluteus medius muscles was seen in the pain-development group when they were standing on the sloped surface compared with level standing. The non–pain-development group responded in the opposite direction by having an increase in coactivation of these muscles, although they did not have a commensurate increase in LBP. Changes seen in both the postural and joint-loading variables that were examined were minimal; in most cases, the sloped surface produced responses that bracketed the postures and loading magnitudes found in level standing, depending on whether the participant was standing on the +16° or –16° surface.
