Work Physiological-Biomechanical Analysis of a Passive Exoskeleton to Support Occupational Lifting and Flexing Processes

NCT03725982 | Completed Results DMC

• 1 other identifier: UKT-2018-AS0-1836
• Study Type: interventional
• Target: 39
• Locations: 1 country
• Sites: 1

Brief Summary

BACKGROUND Industrial tasks that are characterized by high loads, a high repetition rate, and/or awkward body postures, put employees at higher risk to develop work-related musculoskeletal disorders (WRMSD), especially low back pain. To counteract the prevalence of WRMSD, human-robot interaction could improve the power of a person and reduce the physical strain. For the lower back, a reduction of spinal loading could be helpful. The passive upper-extremity exoskeleton Laevo® is developed to support physically heavy work: it supports the back during bending and should, consequently, result in less low back pain (Laevo®, the Netherlands). OBJECTIVES The primary aim of this study is to assess to what extent wearing the exoskeleton changes:

• muscular activity of the erector spinae and biceps femoris muscles;
• knee compression force;
• posture of the upper and lower spine, trunk, hips and knees; ...in different tasks (static vs. dynamic), different trunk postures (trunk flexion vs. trunk flexion and rotation) and different knee postures (straight vs. stooped). Secondary aims of this study are to assess to what extent wearing the exoskeleton changes:
• muscular activity of the trapezius descendens, rectus abdominis, vastus medialis and gastrocnemius medialis;
• perceived discomfort;
• heart rate;
• internal loadings on the spine, using a lumbar spine model;
• the performance of subjects during functional activities (e.g., stair climbing) when wearing the exoskeleton (either turned on or off); ...in different tasks (static vs. dynamic), different trunk postures (trunk flexion vs. trunk flexion and rotation), different knee postures (stoop vs. squat), and different static holding positions(0° vs. 30° vs. 60°) with different weights (0kg vs. 8kg vs. 16kg).

Conditions

Passive Upper-limb Exoskeleton

Keywords

passive exoskeleton; forward trunk flexion; trunk rotation; muscle activity; inverse dynamics; modelling

Outcome Measures

Primary Outcomes (8)

• Muscular Activity of Erector Spinae Muscle.

  Root-mean-square (RMS) of the electrical activity of the erector spinae muscle using surface electromyography (sEMG). The sEMG signals will be continuously recorded, and the RMS will be normalized to a maximal voluntary contraction (%MVE) and averaged over the time period of each experimental condition.

  Average RMS-value (%MVE) over the time period running from baseline (0 min) to directly after (1.5 min) the experimental condition

• Muscular Activity of Biceps Femoris Muscle.

  Root-mean-square (RMS) of the electrical activity of the biceps femoris muscle using surface electromyography (sEMG). The sEMG signals will be continuously recorded, and the RMS will be normalized to a reference voluntary contraction (%RVE) and averaged over the time period of each experimental condition.

  Average RMS-value (%RVE) over the time period running from baseline (0 min) to directly after (1.5 min) the experimental condition

• Posture (Thoracic Kyphosis)

  The posture of the upper spine (thoracic kyphosis) determined using 2D gravimetric position sensors placed on the thoracic vertebrae T1 and lumbar vertebrae L1. The difference value between both sensors reflects the thoracic kyphosis, which was averaged over each experimental condition.

  Average thoracic kyphosis over time period baseline (0 min) to directly after (1.5 min) the experimental condition

• Posture (Lumbar Lordosis)

  The posture of the lower spine (lumbar lordosis) determined using 2D gravimetric position sensors placed on the lumbar vertebrae L1 and L5. The difference value between both sensors reflects the lumbar lordosis, which was averaged over each experimental condition.

  Average lumbar lordosis over time period baseline (0 min) to directly after (1.5 min) the experimental condition

• Posture (Trunk Flexion)

  The posture of the trunk determined using a 2D gravimetric position sensor placed on the thoracic vertebrae T10. The flexion angle of the sensor was averaged over each experimental condition.

  Average trunk flexion over time period baseline (0 min) to directly after (1.5 min) the experimental condition

• Posture (Hip Flexion)

  The posture of the hip (hip flexion) determined using 2D gravimetric position sensors placed on the lumbar vertebrae L5 and the upper leg (femur). The difference value between both sensors reflects the hip flexion, which was averaged over each experimental condition.

  Average hip flexion over time period baseline (0 min) to directly after (1.5 min) the experimental condition

• Posture (Knee Flexion)

  The posture of the knee (knee flexion) determined using 2D gravimetric position sensors placed on the upper leg (femur) and lower leg (tibia). The difference value between both sensors reflects the knee flexion, which was averaged over each experimental condition.

  Average knee flexion over time period baseline (0 min) to directly after (1.5 min) the experimental condition

• Knee Compression Force

  The knee compression force (KCF) is calculated using 2D inverse modelling with continuous recordings from 2D gravimetric position sensors (for joint angles) and a force plate (for ground reaction forces). The average knee compression force will be calculated over each experimental condition and summarized for both the left and right knee, since the task is executed in the frontal plane.

  Average knee compression force (KCF) over the time period running from baseline (0 min) to directly after (1.5 min) the experimental condition

Secondary Outcomes (5)

• Muscular Activity of Rectus Abdominis, Vastus Lateralis, Gastrocnemius Medialis and Trapezius Descendens Muscles.

  Average RMS-value (%RVE) over the time period running from baseline (0 min) to directly after (1.5 min) the experimental condition.

• Rating of Perceived Discomfort (RPD)

  Change from baseline (0 min) to directly after (1.5 min) both experimental conditions

• Heart Rate

  Average heart activity over time period baseline (0 min) to directly after (1.5 min) the experimental condition

• Evaluation of Workload

  Directly after the experimental condition during which the exoskeleton was worn (~ 4.5-6.5 min)

• Self-developed Participant Evaluation Questionnaire

  Directly after the experiment (~2.5 hours)

Study Arms (2)

With exoskeleton, then without exoskeleton

EXPERIMENTAL

Subject will first perform the conditions (simulated, simplified, industrial standing work) with the exoskeleton, then without the exoskeleton.

Device: Laevo ®; Device: No Laevo ®

Without exoskeleton, then with exoskeleton

EXPERIMENTAL

Subject will first perform the conditions (simulated, simplified, industrial standing work) without the exoskeleton, then with the exoskeleton.

Device: Laevo ®; Device: No Laevo ®

Interventions

Laevo ® DEVICE

A passive exoskeleton supporting the lower back during bending and lifting tasks (for more information, visit the manufacturer's website: http://en.laevo.nl/).

Also known as: Exoskeleton

With exoskeleton, then without exoskeleton; Without exoskeleton, then with exoskeleton

No Laevo ® DEVICE

The subjects will not wear any supporting device to perform the experiment, which serves as the control condition.

Also known as: No exoskeleton

With exoskeleton, then without exoskeleton; Without exoskeleton, then with exoskeleton

Eligibility Criteria

• Age: 18 Years - 40 Years
• Sex: male
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)

You may qualify if:

• The participant will give his voluntary informed consent after receiving oral and written information of the content and goal of the study.

You may not qualify if:

• Aged \<18 and \>40 years;
• Female;
• BMI \> 30 kg/m2;
• People under the influence of intoxicants, analgesics, or muscle relaxants;
• Alcohol abuse;
• People with cardiovascular diseases;
• People with a heart pacemaker;
• People with a disability who, due to their restriction at a workplace of this kind, will not be able to participate;
• People with Diabetes Mellitus;
• People with severe muscle contractions of the lower extremities, back or arms;
• People with acute ailments or pain;
• People who are unable to complete the examination program due to language or cognitive obstacles;
• Depending on the degree of severity, people with diseases of the veins and joints of the lower extremities, spine, muscle disorders, symptomatic neurological-psychiatric diseases, acute pain syndromes, maladies or other current diseases.

Sponsors & Collaborators

• University Hospital Tuebingen: lead
• Audi AG: collaborator
• BASF: collaborator
• BMW AG: collaborator
• Dachser Intelligent Logistics: collaborator
• Daimler AG: collaborator
• Deutsche Post AG: collaborator
• Iturri Gruppe: collaborator
• MTU Aero Engines AG: collaborator

Study Sites (1)

Institute of Occupational and Social Medicine and Health Services Research, University Hospital Tübingen

Tübingen, Baden-Wurttemberg, 72074, Germany

Location

Related Publications (2)

• Luger T, Bar M, Seibt R, Rieger MA, Steinhilber B. Using a Back Exoskeleton During Industrial and Functional Tasks-Effects on Muscle Activity, Posture, Performance, Usability, and Wearer Discomfort in a Laboratory Trial. Hum Factors. 2023 Feb;65(1):5-21. doi: 10.1177/00187208211007267. Epub 2021 Apr 16.

  PMID: 33861139 RESULT

• Luger T, Bar M, Seibt R, Rimmele P, Rieger MA, Steinhilber B. A passive back exoskeleton supporting symmetric and asymmetric lifting in stoop and squat posture reduces trunk and hip extensor muscle activity and adjusts body posture - A laboratory study. Appl Ergon. 2021 Nov;97:103530. doi: 10.1016/j.apergo.2021.103530. Epub 2021 Jul 16.

  PMID: 34280658 RESULT

MeSH Terms

Interventions

Exoskeleton Device

Intervention Hierarchy (Ancestors)

Equipment and Supplies

Results Point of Contact

• Title: Tessy Luger
• Organization: Institute of Occupational and Social Medicine and Health Services Research

Tessy.Luger@med.uni-tuebingen.de

004970712984364

Publication Agreements

• PI is Sponsor Employee: No
• Restrictive Agreement: No

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Masking Details: Subjects and experimenters will not be blinded, because it will be obvious which task will be performed by the subjects and measurements need to be tracked by the experimenter.
• Purpose: PREVENTION
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Model Details: 1. Static sorting Six conditions as combination of exoskeleton (without vs. with) and trunk posture (forward flexion vs. flexion + rotation left vs. flexion + rotation right) are investigated in a randomized order. 2. Dynamic lifting Twelve conditions as combination of exoskeleton (without vs. with), work posture (forward flexion vs. flexion + rotation left vs. flexion + rotation right) and knee angle (extended/stoop vs. flexed/squat) are investigated in randomized order. 3. Functional tasks Three tests with two conditions in randomized order (exoskeleton: without vs. with) will be investigated in fixed order (stair-climbing; timed-up-and-go; course with various simulated industrial workstations). 4. Angle-force relation Twelve conditions as combination of exoskeleton (without vs. with), knee angle (extended/stoop vs. flexed/squat) and trunk flexion angle (0 vs. 30 vs. 60 degrees) are investigated in randmized order.

Study Record Dates

• First Submitted: September 27, 2018
• First Posted: October 31, 2018
• Study Start: January 18, 2019
• Primary Completion: May 15, 2019
• Study Completion: May 22, 2019
• Last Updated: July 12, 2023
• Results First Posted: March 31, 2020

Record last verified: 2019-05

Data Sharing

• IPD Sharing: Will not share

Locations

DE (1)