Purpose:
The purpose of this study was to compare the inter-joint coordination during sit-to-stand (STD) and stand-to-sit (SIT) execution between healthy people and people with low back pain.

Methods:
Fifteen healthy adults (age = 45.14 ± 5.18 years) and fifteen age-matched (age = 46.17 ± 8.26 years) people with chronic low back pain were selected voluntarily. They performed three repetitions of STD and SIT movement patterns in their preferred pace. Motion analysis system was used for measuring 3-dimensional (3D) angular displacement of hip, knee and ankle joints during execution of movement patterns. Decomposition indices were analysed and were compared between two groups through Hotelling T² Multivariate Analysis of Variance (MANOVA) and follow-up Analysis of Variance (ANOVA)

Results:
The results showed that there is a significant difference (T² = 18.32, F_{14, 5} = 8.33, p < 0.05) between the groups on decomposition indices. The ANOVA follow-up results showed that there are significant differences between two groups on decomposition indices of the whole pattern of STD (F_{1, 18} = 7.96, p < 0.05), whole pattern of SIT (F_{1, 18} = 5.37, p < 0.05), the first-half phase of STD (F_{1, 18} = 7.26, p < 0.05) and the first-half phase of SIT (F_{1, 18} = 6.33, p < 0.05).

Conclusions:
People with low back pain have dis-coordination in the function of different body parts, and results in pausing of one segment while the other segment moves independently. This knowledge may help in the development of rehabilitation strategies for movement in this population.