An observational study in Musculoskeletal Diseases, Occupational Diseases and Low Back Pain, sponsored by LNA SANTE. Completed at 5 sites in France. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-08-11.
Sponsored by LNA SANTE · Observational
The EXO 2 study assessed whether daily use of an exoskeleton - a wearable mechanical support device - could reduce physical effort and pain in nursing home care staff who regularly perform resident handling tasks such as bed baths and diaper changes.
Care staff in nursing homes (EHPADs) are among the most affected workers by musculoskeletal disorders (MSDs), which are the leading cause of occupational illness and sick leave in the French healthcare sector. Handling of residents in lying positions (decubitus), such as turning, washing, or changing residents in bed, is one of the most physically demanding tasks and a major source of lower and upper back strain.
The HAPO Version 4 exoskeleton is a wearable device worn around the torso that provides mechanical support to the upper body and back during forward-bending tasks. This study is part of a research program that progressively evaluated and improved the HAPO exoskeleton through four earlier phases with LNA Santé care staff.
The main questions this study aimed to answer were:
Does wearing the HAPO exoskeleton daily reduce the perceived effort (physical fatigue) felt in the upper body during resident handling? Does the exoskeleton reduce upper body pain (neck, shoulders, arms, back, hips) over time? How well do care staff integrate the exoskeleton into their daily work routine? Does exoskeleton use reduce workplace accidents and sick leave related to handling?
What participants did:
First 2 weeks (baseline): worked normally without the exoskeleton, completing a daily logbook to record pain and workload Following 11 weeks (intervention): wore the exoskeleton daily during all bed baths and resident changes in decubitus, continuing the daily logbook Completed weekly assessments of perceived effort and satisfaction with the device Were assessed at the end of the study (Day 91) with a final evaluation
The study took place across 5 LNA Santé nursing homes in France and included 35 volunteer care staff members.
Study Design EXO 2 is a prospective, multicenter, single-group, longitudinal observational study with a within-participant before-after design. No control group was included. All eligible volunteer care staff from five LNA Santé nursing home sites were enrolled. Each participant underwent a 2-week baseline observation period (without exoskeleton) followed by an 11-week exoskeleton use period. Data were collected at weekly intervals using standardized tools.
Regulatory classification: This study is classified as Research Not Involving the Human Person (RNIPH) under Article L1121-1 of the French Public Health Code, in the field of human and social sciences applied to occupational health. Data collection and processing comply with CNIL Reference Methodology MR-004, ensuring pseudonymization and confidentiality without requiring review by a Committee for the Protection of Persons (CPP).
Assessment Tools Borg Scale (CR10 version - Perceived Exertion) The Borg CR10 is a validated ratio scale measuring subjective perceived exertion intensity. In this study, it is applied specifically to upper body effort (neck, shoulders, upper arms, back, hips/waist) experienced during resident handling tasks. Completed weekly by participants. Score ranges from 0 (nothing at all) to 10 (maximal exertion); higher score = greater perceived effort. Assessed at baseline (Day 7 and Day 14) and weekly from Day 15 to Day 91.
Visual Analog Scale for Pain (VAS / EVA - Upper Body) A 10 cm visual analog scale measuring daily upper body pain intensity (neck, shoulders, upper arms, back, hips/waist). Completed daily in the participant logbook. Score ranges from 0 (no pain) to 10 (worst imaginable pain); higher score = greater pain intensity. Assessed daily from Day 0 to Day 91.
Exoskeleton Satisfaction Scale A single-item numeric rating scale measuring participant satisfaction with the HAPO V4 device. Completed weekly. Score ranges from 0 (completely dissatisfied) to 10 (completely satisfied); higher score = greater satisfaction. Assessed weekly from Day 15 to Day 91.
Exoskeleton Use Rate (Logbook) Daily recording in the participant logbook of whether the exoskeleton was worn (full use / partial use / not worn) during all resident handling tasks in decubitus. Reasons for non-use are also recorded. Analyzed as proportion of days with full, partial, or no use over the intervention period.
Number of Resident Handling Tasks (Logbook) Weekly count of the number of bed baths and diaper changes performed by the participant during the follow-up period, used as a proxy for workload. Assessed weekly from Day 7 to Day 91.
Absenteeism Rate and Workplace Accidents Unit-level data on restricted sick leave rates and number of work accidents related to resident handling, collected for three comparable periods: pre-study (M-12 to M-10), immediately before (M-3 to M-1), during (M1 to M3), and after the study. Collected from HR records.
Financial and Operational Investment Data At end of study: cost per unit (rental or purchase), human resources required for implementation, training time dedicated to exoskeleton introduction. Collected from each site coordinator.
Statistical Analysis Plan Statistical analyses were performed by a contracted biostatistician using R (v4.3.2 or later). No formal sample size calculation was performed given the exploratory nature and the constraint of volunteer availability (estimated 5-8 participants per site, 5 sites = 30-40 participants).
Descriptive statistics: Continuous variables described as mean ± SD or median [IQR] (normality tested by Shapiro-Wilk); qualitative variables as frequencies and percentages. Rates are accompanied by 95% CIs (Clopper-Pearson method).
Primary and secondary inferential analyses (Borg scale and VAS): At key visits, compared to baseline (V1/V2) using paired parametric (paired t-test) or non-parametric (Wilcoxon signed-rank) tests depending on normality of differences. Longitudinal mixed linear models (with participant as random effect) used to evaluate the temporal effect. Satisfaction data and handling counts analyzed by the same approach, with McNemar tests and Poisson regressions if distributions are discrete. Exoskeleton use (refused/partial/total) analyzed by McNemar test and binomial regression (refusal as event). Multivariate risk factor analyses and correlations across continuous outcomes at different visits are also planned.
All tests bilateral, alpha = 5%; all confidence intervals 95%.
Benefit-Risk Assessment Expected benefits: Reduction in perceived upper body exertion during resident handling tasks; reduction in upper body pain intensity; improvement in working conditions and quality of work life; reduction in workplace accidents and sick leave rates related to resident handling over time.
Identified risks: Physical discomfort during the device adaptation period (estimated first 1-2 months of use); potential redistribution of physical load to previously unloaded muscle groups, which may cause new strain patterns; possible onset of new pain in alternative body regions during the adaptation phase. Participants are informed that withdrawal is voluntary and can occur at any time, without consequence, if discomfort or adverse effects are considered excessive.
752 studies on the registry are indexed under Musculoskeletal Diseases; 164 are open to participants now.
This study's enrollment of 35 is below the median of 120 across 207 observational studies indexed under Musculoskeletal Diseases.
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Volunteer care staff (nursing assistants, registered nurses, personal care assistants, psychomotor therapists) from five LNA Santé nursing homes in France who regularly perform resident handling tasks in decubitus position.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Volunteer nursing home care staff (nursing assistants, registered nurses, personal care assistants) from 5 LNA Santé EHPADs, who regularly perform resident handling tasks in decubitus position (bed baths, diaper changes), enrolled during a 2-week baseline phase without exoskeleton followed by 11 weeks of daily HAPO V4 exoskeleton use. The cohort includes both asymptomatic staff (primary prevention) and staff with prior upper body pain history (secondary prevention)
Device: Passive back-assist exoskeleton (HAPO Version 4)
The HAPO Version 4 is a passive (non-motorized), CE-marked, wearable exoskeleton worn around the torso, designed to provide mechanical support to the dorsal and lumbar spine during forward-bending tasks. It is individually fitted to each participant's morphology. Care staff wore the device daily during all bed baths and diaper changes performed with residents in decubitus position, throughout their working shifts (day and night), from Day 15 to Day 91 (11 weeks). Usage was voluntary on a daily basis. Exoskeleton use did not replace existing patient-handling equipment. The device was supplied and maintained by Ergo Santé (France
Also known as: HAPO CS V4; HAPO exoskeleton; harness exoskeleton
Change from Baseline in Upper Body Perceived Exertion During Resident Handling as Assessed by the Borg CR10 Scale at Day 28, Day 35, Day 63, and Day 91
The Borg CR10 (Category Ratio 10) is a validated ratio scale measuring subjective perceived exertion during physical tasks. In this study, it is applied to upper body effort (neck, shoulders, upper arms, back, hips/waist) experienced during resident handling in decubitus position. Completed weekly by participants. Score ranges from 0 (nothing at all) to 10 (maximal exertion); higher score = greater perceived effort. Baseline is the mean of scores at Day 7 and Day 14 (pre-exoskeleton phase). Change from baseline = weekly score minus mean baseline score.
Time frame: Baseline (Day 7 and Day 14, without exoskeleton) and weekly from Day 15 to Day 91; key analysis time points: Day 28, Day 35, Day 63, and Day 91
Change from Baseline in Daily Upper Body Pain Intensity as Assessed by the Visual Analog Scale (VAS) at Day 21, Day 28, Day 70, and Day 91
A 10 cm Visual Analog Scale measuring daily upper body pain intensity (neck, shoulders, upper arms, back, hips/waist), recorded in the participant's daily logbook. Score ranges from 0 (no pain) to 10 (worst imaginable pain); higher score = greater pain. Baseline is the daily VAS mean during the pre-exoskeleton phase (Day 0 to Day 14). Change from baseline = mean score during intervention minus mean baseline score.
Time frame: Daily from Day 0 to Day 91; key analysis time points: Day 21, Day 28, Day 70, and Day 91
Rate of Exoskeleton Use (Full, Partial, or Refused) During the Intervention Period
Daily recording in the participant logbook of exoskeleton use during resident handling tasks: full use (worn throughout all handling tasks), partial use (worn for some tasks), or not worn (with documented reason). Analyzed as proportion of days with each category of use per participant over the 11-week intervention period. Assessed to evaluate real-world adoption and adherence.
Time frame: Daily from Day 15 to Day 91
Change in Participant Satisfaction with the HAPO V4 Exoskeleton Over the Intervention Period
A single-item numeric rating scale measuring participant satisfaction with the HAPO V4 device, scored weekly by each participant. Score ranges from 0 (completely dissatisfied) to 10 (completely satisfied); higher score = greater satisfaction. Change is assessed from first week of use (Day 15) to end of study (Day 91).
Time frame: Weekly from Day 15 to Day 91
Evolution of Weekly Number of Resident Handling Tasks in Decubitus During the Study Period
Weekly self-reported count of bed baths and diaper changes performed by each participant during their working shift, recorded in the daily logbook. Used as a proxy for occupational workload. Collected to assess whether changes in Borg and VAS scores might be explained by changes in workload rather than the exoskeleton effect.
Time frame: Weekly from Day 7 to Day 91
Change in Restricted Absenteeism Rate in Participating Units Before, During, and After the Exoskeleton Intervention
Unit-level restricted sick leave rates collected from HR records across three comparable periods of three months each: Month -12 to Month -10 (reference period, one year prior to study), Month -3 to Month -1 (immediately before study), and Month 4 to Month 6 (post-intervention period). Compared against Month 1 to Month 3 (during study). Note: individual-level attribution is not possible; unit-level trend analysis only. Interpreted with caution given small sample size.
Time frame: Retrospective data from Month -12 to Month -1 and prospective data from Month 1 to Month 6, collected at end of study
Number of Workplace Accidents Related to Resident Handling in Participating Units Before, During, and After the Exoskeleton Intervention
Unit-level count of workplace accidents related to resident handling collected from HR/occupational health records across four comparable periods of three months each: Month -12 to Month -10 (reference period, one year prior to study), Month -3 to Month -1 (immediately before study), Month 1 to Month 3 (during study), and Month 4 to Month 6 (post-intervention period). Interpreted with caution given the short observation period and small sample size.
Time frame: Retrospective data from Month -12 to Month -10 and Month -3 to Month -1; prospective data from Month 1 to Month 3 and Month 4 to Month 6, collected at end of study (Day 91)
Cost of Exoskeleton Implementation per Nursing Home Unit
End-of-study collection of the total cost of exoskeleton implementation per participating nursing home unit, including device acquisition or rental cost (in euros). Collected from site coordinators at end of the study period.
Time frame: End of study (Day 91)
Human Resources Required for Exoskeleton Implementation per Nursing Home Unit
End-of-study collection of the number of person-hours required for exoskeleton implementation and ongoing support per participating unit, including coordination and follow-up time provided by the risk prevention coordinator and occupational therapist. Collected from site coordinators at end of the study period.
Time frame: End of study (Day 91)
Training Time Dedicated to Exoskeleton Introduction per Nursing Home Unit
End-of-study collection of the total number of hours of training dedicated to introducing the HAPO V4 exoskeleton to care staff per participating unit, as provided by the risk prevention coordinator and occupational therapist. Collected from site coordinators at end of the study period.
Time frame: End of study (Day 91)
Plan to share: No — Individual participant data (IPD) will not be shared. Results of this study will be disseminated through publication in a peer-reviewed scientific journal. Data are governed by the French CNIL Reference Methodology MR-004, which precludes sharing of pseudonymized individual-level data outside the study framework. The small sample size (35 participants across 5 sites) also presents a re-identification risk that precludes IPD sharing. Aggregated, anonymized results and the study protocol will be available upon publication.
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