Influence of wheelchair footrest height on ischial tuberosity pressure in individuals with paraplegia

Impact of wheelchair reclining and leg rest angles on pressure distribution in back, buttocks, and feet: an experimental study in healthy adults

[Purpose] This study aimed to determine the effects of reclining angle and leg rest angle adjustments on pressure distribution in the back, buttocks, and feet in a wheelchair sitting position. [Participants and Methods] Twenty-six healthy young adults participated in this study. Pressures on the back, buttocks, and feet were measured under nine postural conditions with a combination of reclining angles (10°, 30°, and 50°) and leg rest angles (20°, 40°, and 60°). Body pressure distribution was measured for 30 s in each posture using a pressure distribution measuring device, followed by statistical analysis. [Results] Posture adjustments significantly impacted pressure distribution. Pressure was increased on the back and reduced on the buttocks of participants when in the reclining position. The leg rest angle had a minimal effect on foot pressure, but changes in the leg rest angle influenced the balance of pressure between the back and buttocks. [Conclusion] Adjusting wheelchair posture can effectively manage pressure distribution and reduce the risk of pain and pressure ulcers, especially on the back and buttocks. The reclining angle plays a key role in redistributing pressure, making it important for comfort and the prevention of bedsores.

Effects of the wheelchair sitting posture on gluteal pressure

[Purpose] To evaluate the efficacy of the "forward-tilting posture" (the trunk tilted forward against a table) in a wheelchair in relieving gluteal pressure. [Participants and Methods] Thirty-six healthy adults were instructed to sit in a wheelchair assuming the following three postures: (1) both feet placed on the foot support with the trunk upright ("basic sitting posture"), (2) both feet placed on the foot support with the trunk tilted forward against a table ("forward-tilting posture A"), and (3) both feet placed on the floor with the trunk tilted forward against a table ("forward-tilting posture B"). A seat-type sensor pad placed on a wheelchair cushion was used to measure the maximum gluteal pressure and gluteal contact area. [Results] The maximum gluteal pressures in "forward-tilting postures A" and "forward-tilting postures B" were significantly lower than those in the basic sitting posture. The maximum gluteal pressure in "forward-tilting posture B" was significantly lower than that in "forward-tilting posture A". The gluteal contact area in "forward-tilting posture B" was significantly larger than that in "forward-tilting posture A". [Conclusion] The study results indicate that the "forward-tilting posture" in a wheelchair effectively relieves gluteal pressure.

Effect of seat height on manual wheelchair foot propulsion, a repeated-measures crossover study: part 1 - wheeling forward on a smooth level surface

Purpose: To test the hypotheses that, during manual wheelchair foot propulsion forward on smooth level surfaces, lowering the seat height increases speed, push frequency and push effectiveness, and decreases perceived difficulty.Materials and methods: In a repeated-measures crossover study, 50 able-bodied participants used one foot to propel a manual wheelchair 10 m on a smooth level surface at 5 seat heights in random order, ranging from 5.08 cm below to about 5.08 cm above lower-leg length. We recorded Wheelchair Skills Test (WST) capacity scores and used the Wheelchair Propulsion Test (WPT) to calculate speed (m/s), push frequency (cycles/s) and push effectiveness (m/cycle). We also recorded the participants' perceived difficulty (0-4) and video-recorded each trial.Results: WST capacity scores were reduced at the higher seat heights. Using repeated-measures models (adjusted for age, sex and order), there were negative relationships between seat height and speed (p < 0.0001) and push effectiveness (p < 0.0001). Lowering the seat height by 5.08 cm below lower-leg length corresponded to improvements in speed of 0.20 m/s and in push effectiveness of 0.20 m/cycle. The trend for push frequency was also significant (p = 0.003) but the effect size was smaller. Perceived difficulty increased with seat height (p < 0.001). The video-recordings provided qualitative kinematic data regarding the seated "gait cycles".Conclusions: During manual wheelchair foot propulsion forward on smooth level surfaces, lowering the seat height increases speed and push effectiveness, and decreases perceived difficulty.Clinical Trial Registration Number: NCT03330912.Implications for RehabilitationGenerally, wheelchairs used for forward foot propulsion should have a seat height that is 2.54-5.08 cm less than the sitting lower-leg length.Clinicians should, however, take into consideration other functions that may be adversely affected by lowering the seat height.

Trunk Function and Ischial Pressure Offloading in Individuals with Spinal Cord Injury

OBJECTIVE

To determine if there is a relationship between trunk function and offloading of the ischial tuberosities in individuals with Spinal Cord Injury (SCI).

DESIGN

Prospective cross-sectional evaluation.

SETTING

Sub-acute rehabilitation hospital.

PARTICIPANTS

Fifteen non-ambulatory participants with complete or incomplete traumatic and non-traumatic SCI, American Spinal Injury Association Impairment Scale (AIS), Classification A-D.

OUTCOME MEASURES

Isometric trunk strength using a hand held dynamometer, the ability to reach using the multidirectional reach test and offloading times of the ischial tuberosities using a customized pressure mat.

RESULTS

Participants who were able to engage in the multidirectional reach test were defined as "Reachers", whereas individuals who were unable to engage in the multidirectional reach test were defined as "Non-Reachers". Trunk strength was significantly higher in Reachers compared with Non-Reachers (P < 0.05). Offloading times over the left and right ischial tuberosities were lower in Non-Reachers when compared with Reachers, however the results were statistically significant only for offloading over the right ischial tuberosity (P < 0.05). There was no correlation between trunk strength and pressure offloading times for both groups.

CONCLUSIONS

Regardless of an individual's ability to engage in a reaching task, participants with spinal cord injury spent more time offloading the left ischial tuberosity compared with the right ischial tuberosity. The study highlights the need to identify factors that may contribute to offloading behavior in individuals with spinal cord injury who lack sufficient trunk strength.