Lumbar Curvature in Standing and Sitting in Two Types of Chairs: Relationship of Hamstring and Hip Flexor Muscle Length

Abstract

A purpose of this study was to determine the difference in the lumbar curves of subjects while they stood compared with while they sat in two chairs with different seat angles--the Balans Multi-Chair (BMC) and a standard conventional chair (SCC). An additional purpose was to determine the relationship between lumbar curvature and 1) anthropometric factors and hamstring and hip flexor muscle length during standing and during sitting in the two chairs and 2) amount of time spent sitting. Sixty-one men between 20 and 30 years of age served as subjects. Lumbar curve measurements were taken with a flexible ruler with the subjects first standing and then sitting in the two chairs. Hamstring and hip flexor muscle lengths were indicated by range-of-motion measurements taken with a gravity goniometer. Age, number of hours spent sitting per day, upper body length, and right leg length also were recorded. Subjects had significantly more lumbar extension when they sat in the BMC than when they sat in the SCC. Hip flexor length was the only factor that appeared to relate significantly to the difference between the standing lumbar curve and the lumbar curves in the BMC and the SCC.

Gender Responses to Automobile and Office Sitting - Influence of Hip, Hamstring, and Low-Back Flexibility on Seated Postures

“…Previous studies have demonstrated that individuals with relatively short hamstrings tend to exhibit greater posterior pelvic tilt (Bridger et al, 1992) and greater lumbar flexion (Stokes & Abery 1980;Bridger et al, 1989;Bridger et al, 1992) when seated. Conversely, in their study examining whether relationships existed between hamstring muscle length of males and their lumbar postures while sitting on "conventional" and "kneeling" chairs, Link et al (1990) did not find an association between these variables. They attributed the lack of an association found to the ineffectiveness of hamstring muscle action while knees of study participants were flexed.…”

“…However, Stokes and Abery (1980) observed that individuals with the shortest hamstrings exhibited greater lumbar flexion even when knee angles were similar to those in office chair sitting (enclosed angle between thigh and leg ~ 90 degrees); extending the knees by 45 degrees had no additional effect on the sitting lumbar curvature in those who exhibited the least hamstring flexibility. Perhaps if Link et al (1990) had included females in their study or if other sitting conditions were examined, consistent relationships between hamstring flexibility and lumbar curvature during sitting would have surfaced. Although it Fig.…”

“…Although the relationship between hamstring flexibility and seated lumbo-pelvic postures has been examined previously (Stokes & Abery, 1980;Bridger et al, 1989;Link, Nicholson, Shaddeau, Birch, & Gossman, 1990;Bridger et al 1992), it is not yet clear if it holds under realistic workplace conditions, as studies examining postures characteristic of those adopted while performing seated computer work or while driving an automobile are rare. Further, given that females tend to have greater hamstring flexibility than do males (Bridger et al 1992;Wang, Whitney, Burdett, & Janosky, 1993;Youdas, Krause, Hollman, Harmsen, & Laskowski, 2005), it is thus possible that gender-based postural differences in office (Dunk & Callaghan, 2005) and automobile (Coke, Beach, & Callaghan, 2006) sitting are related to differences in hamstring flexibility between males and females.…”

The Influence of Gender and Age on Hamstring Muscle Length in Healthy Adults

“…14,25,37 The subject was positioned supine on an examination table. The lower extremity not being tested was positioned in hip and knee extension.…”

“…14,16, 25 Chan et al 7 combined PA values of HML for men and women, whereas Krabak et al 23 studied only 15 subjects (10 men and 5 women). The defined end point of terminal knee extension varied among investigators, as did HML values.…”