BMC biomedical engineering · 2026
Effect of seat cushion resilience and hardness on lower-limb loading during sit-to-stand.
СтатьяНазвание и аннотация: Перевод пока не подготовлен
Обработка статьи · этапы, ошибки и управление
Загрузка состояния…
Ошибки и ограничения
История · было → стало
Состояние обновляется каждые 5 секунд, пока блок открыт. Процент показывается только там, где известен объём работы. Пауза останавливает продолжение этапа; текущий запрос к источнику может завершиться.
Onoda Yusuke, Ogawa Ami
Аннотация
BACKGROUND: Seat cushion materials affect the mechanical demands of sit-to-stand (STS) movements; however, the effects of specific material properties, such as resilience and hardness, remain unclear. Understanding how these factors influence lower-limb joint moments and movement strategies during STS may contribute to the development of seat designs that assist individuals with reduced lower-limb strength. Therefore, this study aimed to clarify the fundamental mechanical effects of seat cushion resilience and hardness on STS.
METHODS: Fifteen healthy young adults performed STS from five polyurethane foam cushions that differed in resilience (14-55%) and 40% compression hardness (66-336 N). The material ranges were determined with reference to technical documents and a published patent specification to ensure they were within the range commonly used in everyday seating products. Kinematic and kinetic data were collected using a motion capture system and two force plates. Net joint moments were calculated via inverse dynamics, and differences among seat conditions were analyzed using repeated-measures ANOVA or the Friedman test, with Bonferroni-adjusted pairwise comparisons (α = 0.05).
RESULTS: Seat resilience significantly affected the peak hip and knee extensor moments (p < 0.01, η² = 0.35-0.48). High-resilience cushions delayed seat-off timing and maintained greater seat reaction force at the timings of peak hip and knee extensor moments. In contrast, seat hardness mainly influenced horizontal center-of-mass (COM) velocity and hip joint moment (p < 0.01, η² = 0.31-0.37), with softer seats producing larger values.
CONCLUSION: High-resilience cushions delayed seat-off and maintained buttock support for a longer duration, thereby reducing the peak hip and knee extensor moments. In contrast, softer seats promoted a strategy involving greater horizontal momentum generation by the upper body, which consequently required an increased hip extensor moment to decelerate this momentum. Cushions with a resilience of ≥ 53% and 40% compression hardness of ≥ 180 N effectively reduced lower-limb joint loading. The results of this study provide fundamental insights that may contribute to future research on chair design and cushion selection in clinical and caregiving environments.
CLINICAL TRIAL: Not applicable.
METHODS: Fifteen healthy young adults performed STS from five polyurethane foam cushions that differed in resilience (14-55%) and 40% compression hardness (66-336 N). The material ranges were determined with reference to technical documents and a published patent specification to ensure they were within the range commonly used in everyday seating products. Kinematic and kinetic data were collected using a motion capture system and two force plates. Net joint moments were calculated via inverse dynamics, and differences among seat conditions were analyzed using repeated-measures ANOVA or the Friedman test, with Bonferroni-adjusted pairwise comparisons (α = 0.05).
RESULTS: Seat resilience significantly affected the peak hip and knee extensor moments (p < 0.01, η² = 0.35-0.48). High-resilience cushions delayed seat-off timing and maintained greater seat reaction force at the timings of peak hip and knee extensor moments. In contrast, seat hardness mainly influenced horizontal center-of-mass (COM) velocity and hip joint moment (p < 0.01, η² = 0.31-0.37), with softer seats producing larger values.
CONCLUSION: High-resilience cushions delayed seat-off and maintained buttock support for a longer duration, thereby reducing the peak hip and knee extensor moments. In contrast, softer seats promoted a strategy involving greater horizontal momentum generation by the upper body, which consequently required an increased hip extensor moment to decelerate this momentum. Cushions with a resilience of ≥ 53% and 40% compression hardness of ≥ 180 N effectively reduced lower-limb joint loading. The results of this study provide fundamental insights that may contribute to future research on chair design and cushion selection in clinical and caregiving environments.
CLINICAL TRIAL: Not applicable.