Background: Pressure ulcers constitute a major health care burden, characterized by significant morbidity, diminished quality of life, and elevated treatment costs. Wheelchair users are predisposed to pressure ulcers due to sustained ischial and sacral interface pressures resulting from prolonged periods of sitting. Implementation of pressure-relieving interventions, including specialized seating systems engineered to redistribute load and augment the weight-bearing surface area, is critical for mitigating the risk of pressure ulcers. Objective: This study aimed to evaluate a methodology for the custom fabrication of pressure relief cushions, through the user-cushion interface pressure mapping to reduce high-pressure areas and increase contact area in wheelchair users. Methods: First, a validation study was carried out with 7 healthy volunteers. The pressure was determined with an FSA sensor (BodiTrak BT1510, Vista Medical Manufactures), and the cushion profile was obtained through a linear relation with pressure values. In the second phase, 10 cushions for wheelchair users were manufactured and tested. The resulting data from buttock pressure using a flat foam, Jay X2 (gel-foam), ROHO high profile (air), and customed-contoured cushions were analyzed and compared using the following 4 variables: peak pressure, peak pressure index, mean pressure, and contact area. Results: In the validation study, the statistically significant difference between the flat and the custom-contoured cushion showed a better performance in pressure relief for the custom cushion (mean pressure 27.3, SD 4.5 mm Hg and 34.6, SD 3.5 mm Hg; P<.001). Regarding the study with wheelchair users, custom-contoured cushions had lower peak pressure (mean 91.3, SD 36 mm Hg), peak pressure index (mean 69.5, SD 33.7 mm Hg), and mean pressure (34.2, SD 17.4 mm Hg) against flat, Jay X2, and ROHO high profile cushions (P<.005). The contact area (mean 1457.6, SD 254.1 cm²) was greater for the contoured cushion (P<.001) than for flat and ROHO high profile (Permobile) cushions; nevertheless, it was not significantly different from Jay X2 (P=.59). Conclusions: The main finding is that the buttock pressure mapping method produces custom-contoured cushions that, compared with commercial cushions, have good pressure distribution and increased contact area. These results suggest that pressure mapping is a good alternative for manufacturing affordable custom-contoured cushions that can prevent the development of pressure ulcers.

BACKGROUND Pressure ulcers (PU) are a severe health problem with social and health repercussions. Wheelchair users are susceptible to developing PU, so they shall use a cushion to relieve pressure, distribute weight evenly, and increase the contact area. Pressure-relieving cushions at affordable prices are still a need. Custom-contoured cushions were developed using map pressure to address this need. OBJECTIVE The objectives of this study were to (1) develop a methodology to manufacture custom-contoured cushions and (2) evaluate the cushion's performance compared with commercial cushions relating to pressure relief. METHODS First, a validation study was carried out with seven no-wheelchair users. The pressure was determined using an FSA sensor (BodiTrak BT1510), and the cushion profile was obtained through a linear relation. In the second phase, ten cushions for wheelchair users were manufactured and tested. The resulting data from buttock pressure using a flat foam, Jay® X2 (gel-foam), ROHO® HP (air), and customed-contoured cushions was analyzed and compared using the following four variables: peak pressure (PP), peak pressure index (PPI), mean pressure (MP), and contact area (CA). RESULTS In the validation study, the statistically significant difference (P <0.001) between the flat and the contoured cushion showed a better performance in pressure relief for the custom cushion. Regarding the study with wheelchair users, contoured cushions had lower PP (91.3 (36.0) mmHg), PPI (69.5 (33.7) mmHg), and MP (34.2 (17.4) mmHg) against flat, Jay® X2, and ROHO® HP cushions (P <0.005). The CA (1457.6 (254.1) cm2) was greater for the contoured cushion (P <0.001) than for flat and ROHO cushions; nevertheless, it was not significantly different from Jay X2 (P=0.595). CONCLUSIONS The performance of custom-contoured cushions was tested and compared against a flat foam and two commercial cushions. The main finding is that the method of mapping buttock pressure produces low-cost custom-contoured cushions as an efficient pressure relief solution to prevent the development of ulcer pressure.

Inertial Measurement Units (IMUs) have emerged as a practical alternative for quantitative gait analysis. Although numerous studies have demonstrated their capability to estimate spatiotemporal and kinematic gait parameters, there is no clear consensus regarding the relationship between sensor configuration and the gait information that can be extracted. This review aimed to examine the relationship between IMU configuration, including sensor number and anatomical placement, and the quantitative gait parameters obtained, while also considering the processing methods used to derive these parameters. A structured literature review was conducted using PubMed, ScienceDirect, and Web of Science databases. Articles published between 2014 and 2025 were screened according to predefined inclusion and exclusion criteria. Information regarding sensor quantity, sensor placement, extracted gait parameters, processing methods, and validation systems was analyzed. A total of 59 studies were included. Sensor configurations ranged from one to seventeen IMUs. The extracted gait parameters were classified into gait phases, spatiotemporal parameters, and joint kinematics. The findings indicate that the relationship between the number of sensors and the gait parameters obtained is not linear. Sensor placement and signal-processing methods were found to be as important as sensor quantity in determining the gait parameters obtained. The number of IMUs alone is not a reliable predictor of the amount of gait information that can be extracted. Instead, the combination of sensor placement and processing methodology plays a critical role in determining the gait parameters obtained. These findings suggest that IMU configurations should be selected according to the gait parameters of interest rather than by maximizing the number of sensors employed.