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Sliding and lower limb mechanics during sit-stand-sit transitions with a standing wheelchair.

Yang YS, Chen MD, Fang WC, Chang JJ, Kuo CC - Biomed Res Int (2014)

Bottom Line: The maximal resultant forces acting on the knee restraints could reach 23.5% of body weight.A certain amount of ROM at lower limb joints and force acting on the knee was necessitated during sit-stand-sit transitions.Careful consideration needs to be given to who the user of the electric powered standing wheelchair is.

View Article: PubMed Central - PubMed

Affiliation: Department of Occupational Therapy, College of Health Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan.

ABSTRACT

Purpose: This study aimed to investigate the shear displacement between the body and backrest/seat, range of motion (ROM), and force acting on the lower limb joints during sit-stand-sit transitions by operating an electric-powered standing wheelchair.

Methods and materials: The amounts of sliding along the backrest and the seat plane, ROM of lower limb joints, and force acting on the knee/foot were measured in twenty-four people with paraplegia.

Results: Without an antishear mechanism, the shear displacement was approximately 9 cm between the user's body and the backrest/seat surfaces. During standing up, the user's back slid down and the thigh was displaced rearward, but they moved in opposite directions when wheelchair sat back down. A minimum of 60 degrees of ROM at the hip and knee was needed during sit-stand-sit transitions. The maximal resultant forces acting on the knee restraints could reach 23.5% of body weight.

Conclusion: Sliding between the body and backrest/seat occurred while transitioning from sitting to standing and vice versa. A certain amount of ROM at lower limb joints and force acting on the knee was necessitated during sit-stand-sit transitions. Careful consideration needs to be given to who the user of the electric powered standing wheelchair is.

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Related in: MedlinePlus

Representative plot (subject number 10) of the resultant forces acting on the knee as the seat-back angle of the standing wheelchair transformed from sit-to-stand and vice versa.
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fig4: Representative plot (subject number 10) of the resultant forces acting on the knee as the seat-back angle of the standing wheelchair transformed from sit-to-stand and vice versa.

Mentions: Results showed that the resultant forces acting on the knee restraints were significantly larger during sit-to-stand transition than during stand-to-sit transition (P = 0.01). During sit-to-stand transition, the resultant forces increased as the knee was extended (Figure 4). At the standing position, large force was applied on the knee to keep legs straight while standing, but by lowering the seat with increasing the knee flexion angle, the resultant forces acting on the knee were decreased when sitting back. Then, a more detailed analysis comparing separately anterior-posterior and upward-downward forces between these two transitions revealed that the maximal and average anterior force, which are against the knee restraint, were significantly greater during sit-to-stand transition (P < 0.01). But when moving back to sit the average downward forces were significantly larger (P = 0.01). No significant difference in the maximal downward forces was found between these two transitions (P = 0.19). Furthermore, while standing up in a standing wheelchair, an average 74.57 ± 13.67% of body weight by the user was attained onto the feet.


Sliding and lower limb mechanics during sit-stand-sit transitions with a standing wheelchair.

Yang YS, Chen MD, Fang WC, Chang JJ, Kuo CC - Biomed Res Int (2014)

Representative plot (subject number 10) of the resultant forces acting on the knee as the seat-back angle of the standing wheelchair transformed from sit-to-stand and vice versa.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4109664&req=5

fig4: Representative plot (subject number 10) of the resultant forces acting on the knee as the seat-back angle of the standing wheelchair transformed from sit-to-stand and vice versa.
Mentions: Results showed that the resultant forces acting on the knee restraints were significantly larger during sit-to-stand transition than during stand-to-sit transition (P = 0.01). During sit-to-stand transition, the resultant forces increased as the knee was extended (Figure 4). At the standing position, large force was applied on the knee to keep legs straight while standing, but by lowering the seat with increasing the knee flexion angle, the resultant forces acting on the knee were decreased when sitting back. Then, a more detailed analysis comparing separately anterior-posterior and upward-downward forces between these two transitions revealed that the maximal and average anterior force, which are against the knee restraint, were significantly greater during sit-to-stand transition (P < 0.01). But when moving back to sit the average downward forces were significantly larger (P = 0.01). No significant difference in the maximal downward forces was found between these two transitions (P = 0.19). Furthermore, while standing up in a standing wheelchair, an average 74.57 ± 13.67% of body weight by the user was attained onto the feet.

Bottom Line: The maximal resultant forces acting on the knee restraints could reach 23.5% of body weight.A certain amount of ROM at lower limb joints and force acting on the knee was necessitated during sit-stand-sit transitions.Careful consideration needs to be given to who the user of the electric powered standing wheelchair is.

View Article: PubMed Central - PubMed

Affiliation: Department of Occupational Therapy, College of Health Science, Kaohsiung Medical University, 100 Shih-Chuan 1st Road, Kaohsiung 80708, Taiwan.

ABSTRACT

Purpose: This study aimed to investigate the shear displacement between the body and backrest/seat, range of motion (ROM), and force acting on the lower limb joints during sit-stand-sit transitions by operating an electric-powered standing wheelchair.

Methods and materials: The amounts of sliding along the backrest and the seat plane, ROM of lower limb joints, and force acting on the knee/foot were measured in twenty-four people with paraplegia.

Results: Without an antishear mechanism, the shear displacement was approximately 9 cm between the user's body and the backrest/seat surfaces. During standing up, the user's back slid down and the thigh was displaced rearward, but they moved in opposite directions when wheelchair sat back down. A minimum of 60 degrees of ROM at the hip and knee was needed during sit-stand-sit transitions. The maximal resultant forces acting on the knee restraints could reach 23.5% of body weight.

Conclusion: Sliding between the body and backrest/seat occurred while transitioning from sitting to standing and vice versa. A certain amount of ROM at lower limb joints and force acting on the knee was necessitated during sit-stand-sit transitions. Careful consideration needs to be given to who the user of the electric powered standing wheelchair is.

Show MeSH
Related in: MedlinePlus