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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 14, Trial 1) of shear displacement of the user's body sliding along the backrest (BS) and sliding along the seat (SS) as the seat-back angle of the standing wheelchair transformed from sit-to-stand and vice versa.
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fig2: Representative plot (subject number 14, Trial 1) of shear displacement of the user's body sliding along the backrest (BS) and sliding along the seat (SS) as the seat-back angle of the standing wheelchair transformed from sit-to-stand and vice versa.

Mentions: A representative plot of the shear displacements for the back to backrest and thigh to seat was shown in Figure 2. During sit-to-stand transition, the average BS values of each subject were negative, indicating that the upper body was displaced downward, but positive values of SS indicated rearward displacement of the greater trochanter along the seat plane. On the contrary, positive values of BS with negative values of SS were found during a stand-to-sit transition. It was shown that stand-to-sit displaced the upper body into upward direction and thighs into forward direction (Figure 2). The statistical analysis comparing sit-to-stand and stand-to-sit transitions revealed no significant differences in the cumulative values of BS (P = 0.53) and SS (P = 0.07), but significant differences in the range of BS and SS were found (P < 0.05). The range of shear displacements along the backrest plane (BS) was significantly larger during sit-to-stand transition (P < 0.01). On the other hand, during stand-to-sit transition the range of shear displacements along the seat plane (SS) was significantly larger (P = 0.01).


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 14, Trial 1) of shear displacement of the user's body sliding along the backrest (BS) and sliding along the seat (SS) 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

fig2: Representative plot (subject number 14, Trial 1) of shear displacement of the user's body sliding along the backrest (BS) and sliding along the seat (SS) as the seat-back angle of the standing wheelchair transformed from sit-to-stand and vice versa.
Mentions: A representative plot of the shear displacements for the back to backrest and thigh to seat was shown in Figure 2. During sit-to-stand transition, the average BS values of each subject were negative, indicating that the upper body was displaced downward, but positive values of SS indicated rearward displacement of the greater trochanter along the seat plane. On the contrary, positive values of BS with negative values of SS were found during a stand-to-sit transition. It was shown that stand-to-sit displaced the upper body into upward direction and thighs into forward direction (Figure 2). The statistical analysis comparing sit-to-stand and stand-to-sit transitions revealed no significant differences in the cumulative values of BS (P = 0.53) and SS (P = 0.07), but significant differences in the range of BS and SS were found (P < 0.05). The range of shear displacements along the backrest plane (BS) was significantly larger during sit-to-stand transition (P < 0.01). On the other hand, during stand-to-sit transition the range of shear displacements along the seat plane (SS) was significantly larger (P = 0.01).

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