Cervical spine bending: a factor confounding whole trunk and lumbar forward bending range of motion.

CONTEXT Knee bending during tests of lumbar forward bending (FB) may introduce confounding variability. Precluding bending at the knees has, therefore, long been standard protocol to produce valid and reproducible results. However, there is limited research on cervical spine bending as a confounding variable in whole trunk and lumbar FB. OBJECTIVE To examine the role of cervical spine bending on the range of whole trunk and lumbar FB. METHODS Participants were recruited from the faculty, staff, and student population of Nova Southeastern University's Health Professions Division. Each participant underwent 4 FB tests with varying cervical starting positions. Range of motion was measured for whole trunk FB and lumbar FB by using the fingertip-to-floor and double digital inclinometer techniques, respectively. RESULTS Two hundred thirty-six participants met the study criteria. Statistically significant differences were found in both whole trunk (6.96 cm) and lumbar (3.95°) FB range of motion when the cervical spine was backward bent after full spine FB (P<.05). Statistically significant differences were also found in both whole trunk (15.72 cm) and lumbar (7.38°) FB when the cervical spine was backward bent before thoracolumbar spine FB (P<.05). CONCLUSION Cervical spine bending influences the ability of the trunk and lumbar spine to bend forward and is, therefore, a confounding variable during tests of whole trunk and lumbar spine FB.