gms | German Medical Science

Objective: To determine spinal and pelvic positional parameters in upright stance and relate them to the spine and pelvis mobility during bending forward in healthy males.

Material/Methods: Twenty two physically fit males participated in the study, the averages and SD of age, height, and body mass index were [23.76 (SD 3.99) years, 175(SD 0.06) cm, 23.52(SD 2.12) BMI]. Lumbar curvature (LC) and sacral inclination (SI), in relaxed upright stance, and differential lumbar-pelvic motion during forward bending were calculated in the sagittal plane with an electro-goniometer. This consists of two receivers located at L1 and S1 spinous processes, which detected the magnetic pulses emitted by a source. Lumbar curvature is the angle formed between L1 and S1 receivers. Sacral inclination is the angle given by S1-receiver in the sagittal plane [1], [2] which reflects the spatial orientation of the pelvis. The averages and standard deviations were calculated for: the degrees of the LC and SI in relaxed upright stance, the range of spine (S), pelvis (P) motion, and the S/P-ratio during the entire movement of bending forward. Individuals were group according to whether moving either more in pelvis than spine (group 1) or in spine than pelvis (group 2). Twelve subjects with S/P-ratios<1 were assigned to group 1 and ten with S/P-ratios>1 were assigned to group 2

Results: The average S/P-ratio was significantly greater in group 2 (1.4, SD 0.4) than group 1 (0.7, SD 0.2)] (p<.001). In relaxed upright stance: the degrees of lumbar curvature and sacral inclination were significantly greater in group 2 (LC: 38.5º, SD 12.9º; SI: 19.8º, SD 12.9º) than group 1 (LC: 26.2º, SD 6.8º; SI 7.9º, SD 7.6º) (p<.001); and strong and significant correlation (p<.001) was found between lumbar curvature and sacral inclination for each of the two groups (group 1 r=.77, group 2 r=.97). Lumbar curvature in upright stance further showed a very strong and significant correlation with the range of pelvis flexion for group 1 (r=.79, p<.05), and with the range of spine flexion for group 2 (r=.87, p<.01); the regression models have a R2 values of 0.63 for Group 1 and 0.76 for Group 2.

Conclusion: In standing upright the current data showed that as lordosis decreases, the sacral inclination decreases. The males who tended to stand with a more vertical sacrum, and a flatter low back moved more in pelvis than spine (group 1). The males who tended to stand with a more horizontal sacrum, and a lordotic low back moved more in spine than pelvis (group 2). 63% of the pelvis mobility in the group 1 and 76% of the spine mobility in the group 2 are explainable by the lumbar curvature in upright stance.