NCT03725982: ADVANCE

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

Completed NA Results posted Last updated 12 July 2023

What this trial tests

NA trial testing Laevo ® in Passive Upper-limb Exoskeleton in 39 participants. Completed in 22 May 2019.

Timeline

18 January 2019

Primary endpoint
15 May 2019

22 May 2019

Quick facts

Lead sponsor	University Hospital Tuebingen
Phase	NA
Status	Completed
Study type	INTERVENTIONAL
Allocation	randomized
Design	crossover
Masking	none
Primary purpose	prevention
Enrollment	39
Start date	18 January 2019
Primary completion	15 May 2019
Estimated completion	22 May 2019
Sites	1 location across Germany

Drugs / interventions tested

• Laevo ®
• No Laevo ®

Conditions studied

• Passive Upper-limb Exoskeleton — all drugs for Passive Upper-limb Exoskeleton →

Sponsor

University Hospital Tuebingen

Who can join

Adults 18 to 40, male only, with Passive Upper-limb Exoskeleton. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Muscular Activity of Erector Spinae Muscle. Primary · Average RMS-value (%MVE) over the time period running from baseline (0 min) to directly after (1.5 min) the experimental condition

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.

RMS-value during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	11.2	8.6 – 16.0
Without Exoskeleton, Then With Exoskeleton	11.1	8.6 – 14.8

RMS-value during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	12.3	9.0 – 17.6
Without Exoskeleton, Then With Exoskeleton	10.4	7.5 – 13.1

Muscular Activity of Biceps Femoris Muscle. Primary · Average RMS-value (%RVE) over the time period running from baseline (0 min) to directly after (1.5 min) the experimental condition

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.

RMS during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	26.6	16.3 – 39.3
Without Exoskeleton, Then With Exoskeleton	38.7	23.9 – 57.5

RMS during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	35.8	24.4 – 45.8
Without Exoskeleton, Then With Exoskeleton	31.3	20.2 – 55.7

Posture (Thoracic Kyphosis) Primary · Average thoracic kyphosis over time period baseline (0 min) to directly after (1.5 min) the experimental condition

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 angle during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	12.0	7.5 – 15.8
Without Exoskeleton, Then With Exoskeleton	15.4	8.0 – 21.0

Average angle during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	14.5	7.6 – 19.5
Without Exoskeleton, Then With Exoskeleton	13.9	8.8 – 21.3

Posture (Lumbar Lordosis) Primary · Average lumbar lordosis over time period baseline (0 min) to directly after (1.5 min) the experimental condition

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 angle during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	11.8	10.0 – 14.2
Without Exoskeleton, Then With Exoskeleton	13.2	9.4 – 17.7

Average angle during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	12.2	10.1 – 14.0
Without Exoskeleton, Then With Exoskeleton	13.3	10.4 – 16.1

Posture (Trunk Flexion) Primary · Average trunk flexion over time period baseline (0 min) to directly after (1.5 min) the experimental condition

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 angle during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	38.5	36.5 – 41.1
Without Exoskeleton, Then With Exoskeleton	39.6	35.6 – 42.2

Average angle during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	37.9	35.7 – 40.5
Without Exoskeleton, Then With Exoskeleton	39.9	35.9 – 43.5

Posture (Hip Flexion) Primary · Average hip flexion over time period baseline (0 min) to directly after (1.5 min) the experimental condition

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 angle during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	39.9	33.8 – 45.8
Without Exoskeleton, Then With Exoskeleton	33.1	24.7 – 38.4

Average angle during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	29.8	23.6 – 38.3
Without Exoskeleton, Then With Exoskeleton	40.4	32.1 – 47.1

Posture (Knee Flexion) Primary · Average knee flexion over time period baseline (0 min) to directly after (1.5 min) the experimental condition

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 angle during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	16.4	9.4 – 26.4
Without Exoskeleton, Then With Exoskeleton	11.7	3.7 – 17.5

Average angle during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	9.0	2.9 – 16.7
Without Exoskeleton, Then With Exoskeleton	17.9	10.5 – 25.6

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

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 KCF during first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	845	741 – 897
Without Exoskeleton, Then With Exoskeleton	742	609 – 892

Average KCF during second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	807	747 – 868
Without Exoskeleton, Then With Exoskeleton	874	660 – 963

Muscular Activity of Rectus Abdominis, Vastus Lateralis, Gastrocnemius Medialis and Trapezius Descendens Muscles. Secondary · Average RMS-value (%RVE) over the time period running from baseline (0 min) to directly after (1.5 min) the experimental condition.

Root-mean-square (RMS) of the electrical activity of the rectus abdominis, vastus lateralis, gastrocnemius medialis and trapezius descendens muscles using surface electromyography (sEMG). The sEMG signals will be continuously recorded, and the RMS will be normalized to a refeernce voluntary contraction (%RVE) and averaged over the time period of each experimental condition.

Rectus Abdominis

Group	Value	95% CI
Without Exoskeleton	1.85	0.98 – 2.72
With Exoskeleton	1.57	0.88 – 2.26

Vastus Lateralis

Group	Value	95% CI
Without Exoskeleton	3.85	2.06 – 5.64
With Exoskeleton	3.35	1.99 – 4.71

Gastrocnemius Medialis

Group	Value	95% CI
Without Exoskeleton	54.11	30.63 – 77.59
With Exoskeleton	54.11	34.75 – 73.58

Trapezius Descendens

Group	Value	95% CI
Without Exoskeleton	3.77	0.71 – 6.83
With Exoskeleton	4.90	1.21 – 8.60

Rating of Perceived Discomfort (RPD) Secondary · Change from baseline (0 min) to directly after (1.5 min) both experimental conditions

Discomfort (RPD) was assessed using an 11-point numeric rating scale (NRS), ranging from 0 (no discomfort at all) to 10 (maximally imaginable discomfort). It was assessed directly before (0 min) and directly after (1.5 min) each experimental condition. The experimental conditions consisted of either static or dynamic tasks, that lasted up to 1.5 minutes.

RPD after first intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	0.3	± 0.8
Without Exoskeleton, Then With Exoskeleton	0.2	± 0.6

RPD after second intervention period

Group	Value	95% CI
With Exoskeleton, Then Without Exoskeleton	0.5	± 1.0
Without Exoskeleton, Then With Exoskeleton	0.2	± 0.7

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

Continuous recording electrocardiography allows calculating the heart rate, a parameter reflecting the central stress state of the participant. The average heart rate will be calculated per time period.

Group	Value	95% CI
Without Exoskeleton	85.29	± 10.19
With Exoskeleton	83.16	± 10.49

Evaluation of Workload Secondary · Directly after the experimental condition during which the exoskeleton was worn (~ 4.5-6.5 min)

The NASA Task Load Index (TLX) of Hart and Staveland (1988) will be used to evaluate workload. This standardized tool contains six dimensions (mental demand, physical demand, temporal demand, own performance, effort, frustration), of which each scale ranges from from 0 (low) to 100 (high). We will include three dimensions of interest, i.e. physical demand, temporal demand, effort, and calculate the unweighted average of the score of these three dimensions (Hoonakker et al. 2011).

Physical Demand

Group	Value	95% CI
With Exoskeleton	2.31	± 1.58
Without Exoskeleton	1.67	± 1.10

Temporal Demand

Group	Value	95% CI
With Exoskeleton	1.10	± 1.35
Without Exoskeleton	0.88	± 1.01

Effort

Group	Value	95% CI
With Exoskeleton	2.10	± 1.30
Without Exoskeleton	1.49	± 1.00

Sponsor's own description

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).

Publications & conference data

3 peer-reviewed publications reference this trial (live from Europe PMC):

1. Using a Back Exoskeleton During Industrial and Functional Tasks-Effects on Muscle Activity, Posture, Performance, Usability, and Wearer Discomfort in a Laboratory Trial.
   Luger T, Bär M, Seibt R, Rieger MA, et al · · 2023 · cited 36× · PMID 33861139 · DOI 10.1177/00187208211007267
2. Using a Passive Back Exoskeleton During a Simulated Sorting Task: Influence on Muscle Activity, Posture, and Heart Rate.
   Bär M, Luger T, Seibt R, Rieger MA, et al · · 2024 · cited 10× · PMID 35225011 · DOI 10.1177/00187208211073192
3. Effects of a Passive Back-Support Exoskeleton on Knee Joint Loading during Simulated Static Sorting and Dynamic Lifting Tasks.
   Bär M, Luger T, Seibt R, Gabriel J, et al · · 2022 · cited 2× · PMID 36011596 · DOI 10.3390/ijerph19169965