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. 2025 Oct 22;25(21):6507.
doi: 10.3390/s25216507.

Relationship of Seat Interface Pressure to Change in Center of Pressure During Manual Wheelchair Pressure Redistribution Maneuvers

S Andrea Sundaram  1   2   3 , Andrew Hoang  1 , Hannah Kuecker  1 , Sivashankar Sivakanthan  1   2 , Benjamin Gebrosky  3 , Garrett G Grindle  1   3 , Cheng-Shiu Chung  1   3 , Alicia Koontz  1   3   4 , Brad E Dicianno  1   3   5 , Bradley S Duerstock  6 , Rosemarie Cooper  1   2 , Rory A Cooper  1   3   4
Affiliations

Relationship of Seat Interface Pressure to Change in Center of Pressure During Manual Wheelchair Pressure Redistribution Maneuvers

S Andrea Sundaram et al. Sensors (Basel). .

Abstract

Manual wheelchair users (MWUs) are at high risk of developing pressure injuries (PIs) from prolonged static sitting. Clinical practice guidelines suggest periodic pressure redistribution (PR) to mitigate this risk. Prior work has demonstrated that a wheelchair seat pan instrumented with force sensors can track the change in center of pressure (CoP) as MWUs perform PR and use this measurement to infer the direction and degree of a PR. This study's objective was to quantify the relationship between change in CoP and reduction in seat interface pressure (SIP) under the ischial tuberosities for commonly practiced PR maneuvers. A theoretical model relating SIP and change in CoP for forward leaning PR was developed. Participants performed forward, leftward, and rightward leaning PRs while seated on a pressure mat on the test wheelchair with a load cell-instrumented seat pan. Linear mixed-effects models showed that the relationship of SIP and CoP varies by participant. Across participants, the change in SIP for a given change in CoP was greater with sideways than with forward leans. The type of cushion used did not affect the relationship. These findings can be used as part of her real-time smartphone-based coaching system for PI prevention.

Keywords: assistive technology; manual wheelchair; pressure injury.

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Conflict of interest statement

The University of Pittsburgh (PITT) and the U.S. Department of Veterans Affairs (VA) have licensed the Virtual Seating Coach to Permobil, Inc. The VSC is currently on the market under the following: seating function monitoring and coaching system; patent application #US20150209207; Cooper et al. [43]. The MW-VC has unique intellectual property: wheelchair pressure ulcer risk management coaching system and methodology; patent application #US20210267826; Cooper et al. [44].

Figures

Figure 1
Figure 1
Representation of an upright-seated MWU with markings for the coordinate system and axis of leftward leans (r).
Figure 2
Figure 2
Representation of an upright-seated user with corresponding display of CoP. The green sphere on the left represents the user’s center of mass, and the blue dot on the right represents the user’s center of pressure.
Figure 3
Figure 3
User position and CoP during forward lean.
Figure 4
Figure 4
User position and CoP during leftward lean.
Figure 5
Figure 5
Simulation results of CoP magnitude at different trunk angles.
Figure 6
Figure 6
Simulation results of proportional IT pressure verses CoP magnitude.
Figure 7
Figure 7
Upper body angles while executing a forward lean for an AB participant.
Figure 8
Figure 8
Femur angles while executing a forward lean for an AB participant.
Figure 9
Figure 9
Seated center of pressure while executing a forward lean for an AB participant.
Figure 10
Figure 10
Relationship of center of pressure to pitch and roll angles while executing a forward lean for an AB participant.
Figure 11
Figure 11
Proportional IT pressures while executing a forward lean for an AB participant.
Figure 12
Figure 12
Upper body angles while executing a left lean for an AB participant.
Figure 13
Figure 13
Femur angles while executing a left lean for an AB participant.
Figure 14
Figure 14
Seated center of pressure while executing a left lean for an AB participant.
Figure 15
Figure 15
Relationship of center of pressure to pitch and roll angles while executing a left lean for an AB participant.
Figure 16
Figure 16
Proportional IT pressures while executing a left lean for an AB participant.
Figure 17
Figure 17
Fitted lines for MWU participants’ forward lean.
Figure 18
Figure 18
Fitted lines for MWU participants’ left lean.
Figure 19
Figure 19
Comparison of theoretical and fitted linear coefficients for AB participants’ forward lean.
Figure 20
Figure 20
Comparison of theoretical and fitted linear coefficients for MWU participants’ forward lean.
Figure 21
Figure 21
Mean and difference in theoretical and fitted linear coefficients for AB participants’ forward lean.
Figure 22
Figure 22
Mean and difference in theoretical and fitted linear coefficients for MWU participants’ forward lean.
Figure 23
Figure 23
Good fit of forward lean data to angle model equation.
Figure 24
Figure 24
Poor fit of forward lean data to angle model equation.
Figure 25
Figure 25
Inconsistent forward lean results in poor fit to angle model equation.
Figure 26
Figure 26
Comparison of theoretical and fitted b coefficients for AB participants’ forward lean.
Figure 27
Figure 27
Mean and difference in theoretical and fitted b coefficients for AB participants’ forward lean.
Figure 28
Figure 28
Comparison of theoretical and fitted b coefficients for MWU participants’ forward lean.
Figure 29
Figure 29
Mean and difference in theoretical and fitted b coefficients for MWU participants’ forward lean.
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