Lumbar spine flexion and extension extremes of motion in women of different age and racial groups: the WIN Study.

Study Design: Observational.

Objective: To provide normative values of lumbar flexion and extension for women of different age and racial groups.

Summary Of Background Data: Spinal range of motion (ROM) is one of the AMA Guides criteria used to estimate level of impairment and subsequent compensation entitlement. Studies show that spinal ROM varies with age, gender, and possibly race/ethnicity, but adequate normative values for different age and racial/ethnic groups do not exist.

Methods: A cohort of free-living women was recruited for the Women's Injury Study at The Cooper Institute in Dallas. Originally, 917 women between the ages of 20 and 83 (M = 52 +/- 13) underwent an orthopedic examination including lumbar spine flexion and extension measurement using an electronic inclinometer. Measurements were taken in the fully extended and flexed positions, respectively. This removes the influence of initial resting posture and is termed "extreme of motion" (EOM) as opposed to ROM. Age and racial groups were compared using a 2-way multivariate analysis of variance (MANOVA) followed with post hoc tests.

Results: Means (+/-SD) were calculated for racial (white, N = 619, African-American, N = 147) and age groups (young, 20-39 years, n = 126; middle, 40-59 years, n = 412; older, > or = 60 years, n = 228). Lumbar extension for African-American women (60.1 degrees) was significantly greater (P < 0.05) than for white women (52.6 degrees), but flexion was not different (15.2 degrees and 17.0 degrees), respectively. Extension EOM for the young group (61.6 degrees) was greater (P < 0.05) than the middle (56.6 degrees) and older (50.8 degrees) groups. Extension difference between the middle and older groups was significant. Flexion EOM for the young group (20.1 degrees) was greater (P < 0.05) than the middle (15.2 degrees) and older (12.8 degrees) groups. The difference in flexion between the middle and older groups was not significant.

Conclusion: Normative values of lumbar extension are different for white and African-American women. Values for lumbar flexion and extension are different between age groups. Different criteria should be used to estimate impairment level in women of different racial and age groups.