The effects of body position on the material properties of soft tissue in the human thigh

Scott, Justin; Chen, Sheng; Roccabianca, Sara; Bush, Tamara Reid

doi:10.1016/j.jmbbm.2020.103964

Cited by 5 publications

(8 citation statements)

References 41 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Loading reduced soft tissue thicknesses of the buttocks, particularly MT thickness. The MRI loader showed the same trends in force deflection responses as reported in prior work by the authors [21]. Lastly, the reduction in tissue thickness with loading was influenced by the total unloaded tissue thickness, but not influenced by fatty infiltration of the gluteus maximus muscle.…”

Section: Discussionsupporting

confidence: 79%

“…Stretch was calculated as (loaded tissue thickness)/(unloaded tissue thickness) from the MRI data. The stress and stretch data were modeled using an incompressible first-order Ogden material and compared to previously published data measured in the proximal femur soft tissue during progressive loading [21]. The relationship between the stress and stretch in the first-order Ogden model is described in Eq.…”

Section: Soft Tissue Changes With Loadingmentioning

confidence: 99%

“…Second, evaluating unloaded soft tissue in a seated position for the buttocks and thighs is difficult, given that the body needs to be balanced and suspended with minimal pressure to image soft tissue while maintaining a neutral pelvis. Approaches have included using a toileting chair, using chairs with gaps in the seat base and sitting just on the front edge of a chair, and sitting upon the coccyx (tailbone) [11,[19][20][21]. Third, loaded soft tissue can also be difficult for both US and MRI, given the challenges to properly provide a seated position that is safe and compatible with restricted imaging environments.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A novel approach for quantitative imaging of the seated anatomy of the buttocks using ultrasound and MRI

Mogale,

Scott,

Schanz

et al. 2023

Front. Phys.

Self Cite

View full text Add to dashboard Cite

Background: Pressure injuries are commonly noted in individuals who use wheelchairs for mobility and sit for prolonged periods. Understanding soft tissue composition is an essential part of treating and preventing pressure injuries. This study proposes novel approaches for imaging the soft tissue of the buttocks in unloaded and loaded conditions using ultrasound (US) and magnetic resonance imaging (MRI).Methods: The soft tissue of the buttocks was measured in able-bodied participants (n = 26, 50% female) and one male with a spinal cord injury using an innovative chair that allowed seated US acquisition of the buttocks and a newly developed MRI compatible loader. The US test–retest reliability (reproducibility) of buttocks soft tissue was assessed, and US was validated with MRI. Soft tissue was measured between the peak of the ischial tuberosity (IT) and proximal femur and the skin. MRI was used to quantify the fat fraction of the gluteus maximus muscle, with the goal of determining the influence of intramuscular fat on loaded soft tissue responses and was used to assess tissue thickness during buttocks loading.Results: US reproducibility was excellent, ICC = 0.934–0.981, with no statistical differences between scan days. Coefficients of variation (CVs) between visits ranged from 2.5% to 7.4% for loaded and unloaded tissue. US and MRI measures of tissue thickness were significantly correlated (r = 0.68–0.91, p ≤ 0.001). US underestimated the unloaded tissue thicknesses, with a mean bias of 0.39–0.56 cm. When the buttocks were loaded, US- and MRI-measured total tissue thickness was reduced by up to 64.2% ± 9.1% (p < 0.001). The US- and MRI-unloaded total soft tissue of the IT was correlated with loaded tissue thickness (r = 0.54–0.67, p ≤ 0.027). Intramuscular fat of the gluteus maximus was not correlated to changes in muscle thickness with loading (r = 0.05, p > 0.05).Conclusion: We have developed and validated a novel US methodology using MRI as a comparison measure to investigate soft tissue anatomy and deformation during sitting and loading. The ability to obtain such data in the loaded condition is unique and fills an unmet need in understanding loading and pressure injury formation.

show abstract

Section: Discussionsupporting

confidence: 79%

Section: Soft Tissue Changes With Loadingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A novel approach for quantitative imaging of the seated anatomy of the buttocks using ultrasound and MRI

Mogale,

Scott,

Schanz

et al. 2023

Front. Phys.

Self Cite

View full text Add to dashboard Cite

show abstract

“…Third, we performed our experiment only on young Japanese males, but changes in the participant demographics could affect the mechanical behavior of soft tissues (Derby & Akhtar, 2015). Eventually, we conducted our experiment only when the upper arm was fully extended on the experimental table (Figure 3b); however, different upper arm positions may change the soft tissue stiffness (Scott et al, 2020). To further validate our findings, future studies will examine soft tissue stiffness in different locations of the body, a broader demographic range from young adults to seniors, and various body positions.…”

Section: Discussionmentioning

confidence: 99%

Analyzing soft tissue stiffness of human upper arms during physical dynamic and quasi‐static impacts in human–machine interaction

Rajaei

Fujikawa

Yamada

2023

Hum Ftrs & Erg Mfg Svc

View full text Add to dashboard Cite

Knowledge of the changes in the behavior of human soft tissue stiffness during physical impact in human–machine interaction (HMI) plays a vital role in the development of biofidelity testing devices such as a human dummy. These testing devices are widely applied as an effective means to validate the safety of machinery during dynamic or static contact with humans in HMI. In this study, we assess changes in soft tissue stiffness in the upper arm of individuals under both dynamic (0.7 and 0.25 m/s) and quasi‐static (QS) impacts under a constrained contact condition. Three impactor shapes (cylindrical, cubic, and spherical) are used in this study. Impact experiments are conducted using impactors attached to a pendulum. The soft‐tissue displacement is determined using an ultrasound device. The impact force‐displacement curves illustrate the nonlinear behavior of the soft tissue stiffness under both dynamic and QS impacts. By utilizing the “Linear Mixed Model” statistical analysis, we found that changes in the impact velocity significantly influenced the changes in the nonlinear behavior of soft tissue stiffness while there was no significant effect of the changes in the impactor shape on the nonlinear behavior of the soft tissue stiffness. Additionally, we revealed that the changes in the soft tissue stiffness are influenced by the size of the contact area. Moreover, we demonstrated a range of changes in soft tissue stiffness for different impact velocities, which provide valuable information for developing future validation test devices in HMI, such as the design and evaluation of dummy skin.

show abstract

“…One reason could be that the material properties of soft tissues might not be appropriate. According to Scott et al (2020) , the apparent soft tissue material properties could be significantly different even for the same subject from different positions. The soft tissue of the adult HBM was simulated with an isotropic homogeneous Neohookean material not accounting for regional difference of properties, the presence of muscles, their fascia, or the possible sliding between structures.…”

Section: Discussionmentioning

confidence: 99%

PIPER adult comfort: an open-source full body human body model for seating comfort assessment and its validation under static loading conditions

Liu

Beillas

Wang

2023

Front. Bioeng. Biotechnol.

View full text Add to dashboard Cite

Introduction: In this paper we introduce an adult-sized FE full-body HBM for seating comfort assessments and present its validation in different static seating conditions in terms of pressure distribution and contact forces.Methods: We morphed the PIPER Child model into a male adult-sized model with the help of different target sources including his body surface scans, and spinal and pelvic bone surfaces and an open sourced full body skeleton. We also introduced soft tissue sliding under the ischial tuberosities (ITs). The initial model was adapted for seating applications with low modulus soft tissue material property and mesh refinements for buttock regions, etc. We compared the contact forces and pressure-related parameters simulated using the adult HBM with those obtained experimentally from the person whose data was used for the model development. Four seat configurations, with the seat pan angle varying from 0° to 15° and seat-to-back angle fixed at 100°, were tested.Results: The adult HBM could correctly simulate the contact forces on the backrest, seat pan, and foot support with an average error of less than 22.3 N and 15.5 N in the horizontal and vertical directions, which is small considering the body weight (785 N). In terms of contact area, peak, and mean pressure, the simulation matched well with the experiment for the seat pan. With soft tissue sliding, higher soft tissue compression was obtained in agreement with the observations from recent MRI studies.Discussion: The present adult model could be used as a reference using a morphing tool as proposed in PIPER. The model will be published openly online as part of the PIPER open-source project (www.PIPER-project.org) to facilitate its reuse and improvement as well as its specific adaptation for different applications.

show abstract

The effects of body position on the material properties of soft tissue in the human thigh

Cited by 5 publications

References 41 publications

A novel approach for quantitative imaging of the seated anatomy of the buttocks using ultrasound and MRI

A novel approach for quantitative imaging of the seated anatomy of the buttocks using ultrasound and MRI

Analyzing soft tissue stiffness of human upper arms during physical dynamic and quasi‐static impacts in human–machine interaction

PIPER adult comfort: an open-source full body human body model for seating comfort assessment and its validation under static loading conditions

Contact Info

Product

Resources

About