1. “The variability in lumbar lordosis and sacrum orientation in repetitive upright standing postures decreases with the number of standing phases.” The idea is that test subjects will become familiar with the test setup and should know how to pose for the tests, which would decrease variability.
2. “Age and gender significantly affect the variation in lumbar lordosis and sacrum orientation.” This is based on two previous studies that found a correlation between gender and age with lumbar lordosis and sacrum orientation. (2,3)
3. “Low back pain] patients show a significantly greater variability in lumbar lordosis and sacrum orientation than asymptomatic subjects due to pain-related functional adaptation and/ or pain and movement avoidance behaviour.”
4. “Athletes with a higher and more uniform fitness level stand more reproducible than non-athletes. ” The researchers assumed that athletes have better neuromuscular and motor control that allow them to have more stability and reproducible posture than non-athletes, especially those with low back pain.
Well, the results do not find significant differences between the back-pain free group and those with low back pain. Not only were the joint angles similar between the asymptomatic and back pain group and between the non-athlete and athletic group, each time the subject performed an exercise and return to being a statue for two seconds, no two standing postures were alike.
“In six repeated standing phases, 51% of all asymptomatic women and men showed on average variations in lumbar lordosis between 10% and 20%; 20% between 20% and 30% and 6% between 30% and 40%. In the sacrum orientation, 42% of all asymptomatic women and 29% of all asymptomatic men revealed variations of 10%-20%. Interestingly, 18% of all asymptomatic men showed variations in sacrum orientation >40%. For variations of 10–20%, sacrum orientation and lumbar lordosis did not show significant differences between repeated measurements,” the researchers wrote.
“Therefore, it is important to understand that the variability in standing is not predictable but random, and thus does not reflect an individual specific behavioral pattern which can be reduced, for example, by repeated standing phases,” the researchers advised.
The findings in this study further supports a heap of previous studies that find a poor association of posture and back pain and various types of pain.
1. Schmidt H, Bashkuev M, Weerts J, Graichen F, Altenscheidt J, Maier C, Reitmaier S. How do we stand? Variations during repeated standing phases of asymptomatic subjects and low back pain patients. J Biomech. 2018 Mar 21;70:67-76. doi: 10.1016/j.jbiomech.2017.06.016.
2. Pries, E., Dreischarf, M., Bashkuev, M., Schmidt, H., 2015b. Application of a novel spinal posture and motion measurement system in active and static sitting. Ergonomics, 1-6.
3. Dreischarf M, Albiol L, Rohlmann A, et al. Age-Related Loss of Lumbar Spinal Lordosis and Mobility – A Study of 323 Asymptomatic Volunteers. Shi X-M, ed. PLoS ONE. 2014;9(12):e116186. doi:10.1371/journal.pone.0116186.
4. Consmüller T, Rohlmann A, Weinland D, Druschel C, Duda GN, Taylor WR. Velocity of Lordosis Angle during Spinal Flexion and Extension. Milanese S, ed. PLoS ONE. 2012;7(11):e50135. doi:10.1371/journal.pone.0050135.