Efficacy of a Passive Lower Limb Exoskeleton in Reducing Plantar Pressure and Injuries From Prolonged Standing

NCT ID: NCT06995469

Last Updated: 2025-06-04

Basic Information

• Recruitment Status: COMPLETED
• Total Enrollment: 25 participants
• Study Classification: OBSERVATIONAL
• Study Start Date: 2025-03-01
• Study Completion Date: 2025-05-26

Brief Summary

This quasi-experimental study evaluates the effectiveness of a passive lower-limb exoskeleton (Chairless Chair® 2.0) in redistributing plantar pressure and reducing injuries caused by prolonged standing in workplace settings. Conducted on 25 participants, the research measured plantar pressure, body sway, and postural stability with and without the exoskeleton using a pressure platform. Additionally, user fatigue and satisfaction were assessed through validated questionnaires (Borg CR10, QUEST 2.0). The results aim to determine the device's preventive potential regarding musculoskeletal and circulatory issues, contributing to improved ergonomic health and work performance.

Detailed Description

Prolonged standing is a common requirement in various professional sectors (e.g., healthcare, industry), and is associated with increased risks of musculoskeletal and circulatory disorders, especially in the lower limbs. Conditions such as plantar fasciitis, chronic venous insufficiency, and pressure ulcers are prevalent. These affect worker health, comfort, and productivity, and impose economic burdens on employers and healthcare systems.

Objective To evaluate the effectiveness of a passive exoskeleton for the lower limbs (Chairless Chair® 2.0) in redistributing plantar pressure and reducing musculoskeletal injuries associated with prolonged standing. The study also investigates the device's influence on postural stability, perceived fatigue, and user comfort.

Methodology Study design: Quasi-experimental with repeated measures (participants act as their own control).

Participants: 25 adult workers (aged 18-60), with ≥6 months of exposure to prolonged standing at work. Exclusion criteria included pre-existing musculoskeletal or circulatory disorders and use of orthopedic devices.

Device: Chairless Chair® 2.0 by Noonee Germany GmbH-a passive, non-powered exoskeleton enabling users to alternate between standing and semi-sitting positions.

Tools and Measurements:

Podoprint S4 pressure platform to measure:

Plantar pressure distribution (forefoot, midfoot, heel)

Body sway and stability (center of pressure displacement)

CR10 Borg scale for fatigue

QUEST 2.0 for usability and satisfaction

Data Analysis:

Quantitative analysis using SPSS and JASP

Paired t-tests or Wilcoxon tests for comparisons

Spearman correlations and Chi-square tests for categorical relationships

Statistical significance set at p < 0.05

Key Variables Dependent: Plantar pressure (kPa), body sway (cm²), postural stability (mm/s), fatigue perception, comfort.

Independent: Use of exoskeleton, age, gender, BMI, type of footwear, reported discomfort.

Ethical and Legal Framework Ethical approval granted by the Comité de Ética de la Universidad Católica de Valencia (CEI).

Compliance with LOPDGDD, GDPR, and Declaration of Helsinki.

Informed consent obtained; anonymity and data protection were strictly maintained.

Expected Outcomes Reduction in peak plantar pressure and postural sway when using the exoskeleton.

Improvement in stability and fatigue levels.

Enhanced user comfort and satisfaction, making the device a feasible ergonomic intervention.

Significance This study seeks to fill a gap in scientific literature regarding the biomechanical benefits of passive lower-limb exoskeletons in real work environments, providing evidence for their role in injury prevention, ergonomic improvement, and worker well-being.

Conditions

Health-Related Behavior

Study Design

• Observational Model Type: COHORT
• Study Time Perspective: PROSPECTIVE

Study Groups

Exoskeleton

This single-group cohort consists of participants assessed under two conditions: (1) performing prolonged standing tasks with the use of a passive lower-limb exoskeleton (Chairless Chair® 2.0) and (2) performing the same tasks without the exoskeleton.

Each participant serves as their own control in a within-subject, repeated-measures design to evaluate changes in plantar pressure distribution, postural stability, perceived fatigue, and device usability.

Chairless Chair® 2.0 Passive Lower-Limb Exoskeleton

Intervention Type: PROCEDURE

Participants used a passive lower-limb exoskeleton (Chairless Chair® 2.0) during their regular work tasks involving prolonged standing. The device enables a semi-seated posture without the need for external power, aiming to reduce lower limb strain.

The intervention involved each participant performing their typical standing tasks once with the exoskeleton and once without it, in a within-subject repeated-measures design. Each participant served as their own control.

Objective data were collected using a plantar pressure platform (Podoprint S4, Namrol) to measure:

Plantar pressure distribution

Postural stability

Body sway

Interventions

Chairless Chair® 2.0 Passive Lower-Limb Exoskeleton

Participants used a passive lower-limb exoskeleton (Chairless Chair® 2.0) during their regular work tasks involving prolonged standing. The device enables a semi-seated posture without the need for external power, aiming to reduce lower limb strain.

The intervention involved each participant performing their typical standing tasks once with the exoskeleton and once without it, in a within-subject repeated-measures design. Each participant served as their own control.

Objective data were collected using a plantar pressure platform (Podoprint S4, Namrol) to measure:

Plantar pressure distribution

Postural stability

Body sway

Intervention Type: PROCEDURE

Eligibility Criteria

Inclusion Criteria

Adults aged 18 to 60 years

Currently employed in jobs requiring prolonged standing (≥4 hours/day)

Minimum 6 months of work experience in such standing-intensive roles

Physically capable of performing normal job tasks

Able and willing to provide informed consent

Exclusion Criteria

Diagnosis of musculoskeletal or circulatory conditions (e.g., plantar fasciitis, varicose veins, chronic venous insufficiency)

Current use of orthopedic or ergonomic devices, such as foot orthoses

Uncontrolled medical conditions that may pose a risk (e.g., uncontrolled hypertension)

Pregnancy

Inability to understand or comply with study procedures

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 60 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Fundación Universidad Católica de Valencia San Vicente Mártir

OTHER

Sponsor Role: lead

Responsible Party

Javier Ferrer Torregrosa

HEAD OF PODIATRY DEPARTMENT

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

JAVIER FERRER TORREGROSA, Dr.

Role: PRINCIPAL_INVESTIGATOR

UNIVERSIDAD CATOLICA DE VALENCIA

Locations

Clinicas UCV

Valencia, València, Spain

Countries

Spain

References

Liu L, Wei W, Zheng K, Diao Y, Wang Z, Li G, Zhao G. Design of an Unpowered Ankle-Foot Exoskeleton Used for Walking Assistance. Annu Int Conf IEEE Eng Med Biol Soc. 2021 Nov;2021:4501-4504. doi: 10.1109/EMBC46164.2021.9630707.

Reference Type: BACKGROUND

PMID: 34892218 (View on PubMed)

Steinhilber B, Seibt R, Rieger MA, Luger T. Postural Control When Using an Industrial Lower Limb Exoskeleton: Impact of Reaching for a Working Tool and External Perturbation. Hum Factors. 2022 Jun;64(4):635-648. doi: 10.1177/0018720820957466. Epub 2020 Sep 28.

Reference Type: BACKGROUND

PMID: 32988243 (View on PubMed)

Kong YK, Park CW, Cho MU, Kim SY, Kim MJ, Hyun DJ, Bae K, Choi JK, Ko SM, Choi KH. Guidelines for Working Heights of the Lower-Limb Exoskeleton (CEX) Based on Ergonomic Evaluations. Int J Environ Res Public Health. 2021 May 13;18(10):5199. doi: 10.3390/ijerph18105199.

Reference Type: BACKGROUND

PMID: 34068352 (View on PubMed)

Other Identifiers

UCV/2024-2025/030

Identifier Type: -

Identifier Source: org_study_id