Feasibility and Usability of Intrinsic Capacity Monitoring With Eforto and Its Predictive Value for Health Outcomes in Older Community-dwelling Persons

Study Overview
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Brief Summary
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In this study, 160 community-dwelling older adults (65 years and older) will be provided with an eforto® system to self-monitor their muscle fatigability and self-perceived fatigue for 2 consecutive days per week during 12 months (if needed with assistance by an informal caregiver). Preferably, the participants will use their own smartphone because mitigating smartphone-use-related issues. The aims of the study are: to evaluate the usability and feasibility of self-monitoring intrinsic capacity by using the eforto® system in the home setting. to investigate if changes and variability in intrinsic capacity as measured with eforto® (muscle fatigability and self-perceived fatigue), are related to changes in frailty status, functional independency and quality of life. to explore whether intrinsic capacity as measured with eforto® (muscle fatigability and self-perceived fatigue) is related to circulating inflammatory biomarkers.

Detailed Description
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Investigational device: The eforto® system was developed based on approximatively 20 years of scientific research on handgrip muscle fatigability performed by the Frailty in Ageing research department (see https://fria.research.vub.be/) and in collaboration with top-level international partners. The eforto® system allows self-assessment of muscle fatigability and self-perceived fatigue in older adults and functions as a monitoring tool for intrinsic capacity. It is a small device, easy to use, and suitable for home measurements as well as hospital settings. When used correctly, the measurements cause no discomfort and can be performed repeatedly. The rubber bulb connects to a smartphone application that provides verbal test instructions to the participant. The app will guide the participant during the test and automatically provide motivational cues via audio. The test results are aggregated and stored in a cloud platform where the researcher can manage subjects, access the test data and export it for further analysis. The mobile app supports Dutch, French and English. In a previous study, eforto® was clinically validated against a gold-standard pressure gauge in n=61 community-dwelling older adults, n=26 hospitalized geriatric patients and n=25 older hip fracture patients. Moreover, the usability and acceptance of eforto® self-monitoring (1 week) was demonstrated in a sample of n=30 community dwelling older persons aged between 83 and 95 years old. (paper submitted for publication in international peer-reviewed journal) Procedures: After the recruitment, a researcher will estimate whether the participant is eligible for the study during a eligibility check by a telephone call and legally capable to provide consent. After informed consent is given, baseline measurements will take place. These measurements will be reassessed after 6 months and 12 months. After an individual information session explaining how to use eforto®, the participant will be instructed to perform the eforto® measurements for 2 consecutive days per week for 12 months at home (if needed with assistance by an informal caregiver). Preferentially, the researcher will install the eforto® application on the smartphone of the participant. The home measurements will be continued for 12 months or until withdrawal of the participant. During the study, there will be a monthly telephone contact between participants and researchers in order to register technical problems, and self-reported changes in health situation.

Official Title
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Feasibility and Usability of Intrinsic Capacity Monitoring With Eforto and Its Predictive Value for Health Outcomes in Older Community-dwelling Persons

Conditions
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Frailty

Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Aged 65 years and over Living in the community (independently at home or at home assisted by an informal caregiver or in assistive housing) Being able to operate the basic functions of a smartphone (if needed with assistance by an informal caregiver): using a smartphone at least for calls and minimum 1 other application Understanding Dutch or French Simple Frail Scale score <3 Exclusion Criteria: Being unable to participate in the assessments due to: Physical impairments (e.g. unable to stand up or walk) Cognitive impairments (unable to understand the test instructions and/or Mini Mental State Examination (MMSE) score <23/30) Functional disability of the dominant upper extremity (pare-sis/paralysis, tremor or recent surgery)

Ages Eligible for Study
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Minimum Age: 65 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 1 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 2 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 3 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 4 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 5 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 6 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 7 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 8 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 9 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 10 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 11 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 12 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 13 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 14 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 15 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 16 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 17 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 18 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 19 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 20 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 21 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 22 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 23 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 24 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 25 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 26 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 27 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 28 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 29 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 30 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 31 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 32 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 33 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 34 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 35 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 36 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 37 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 38 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 39 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 40 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 41 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 42 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 43 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 44 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 45 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 46 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 47 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 48 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 49 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 50 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 51 | 
| Usability of the eforto® system | A checklist of potential technical problems (11 questions) related to the eforto® system that can occur during the study. Options for answer: yes or no; if 'yes' => clarify the technical problem. | Week 52 | 
| Feasibility of the eforto® system | An self-reported questionnaire (12 questions) based on the technology acceptance model (the Unified Theory of Acceptance Use of Technology (UTAUT)). Options for answer: 1-5. 1 is 'Strongly disagree', 5 is 'Strongly agree'. | End of the study (week 52) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The correlation between muscle fatigability and frailty status. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The frailty status will be assessed by the frailty assessments: a) Fried Criteria: consists of five components: unintentional weight loss, weakness, exhaustion (low energy level), slowness (slow gait) and low physical activity. This is operationalised through self-reported questions and non-invasive tests like grip strength using eforto® and timed 4-meter walking. Frailty is defined as having ≥3 of the 5 components, pre-frail participants have 1 or 2 components and robust participants have none of the components. b) Groningen Frailty Indicator: this is a 15-item self-reported questionnaire. Each positive answer is given a score of 1. A score of ≥4 indicates moderate to severe frailty. | Baseline | 
| The correlation between self-perceived fatigue and frailty status. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The Multidimensional Fatigue Inventory will be assessed in the context of self-perceived fatigue. The frailty status will be assessed by a) Fried Criteria: consists of 5 components: unintentional weight loss, weakness, exhaustion (low energy level), slowness (slow gait) and low physical activity. This is operationalised through self-reported questions and non-invasive tests. Frailty = having ≥3 of the 5 components, pre-frail = having 1 or 2 components and robust = having none of the components. b) Groningen Frailty Indicator: = 15-item self-reported questionnaire. Each positive answer is given a score of 1. A score of ≥4 indicates moderate to severe frailty. | Baseline | 
| The correlation between muscle fatigability and frailty status. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The frailty status will be assessed by the frailty assessments: a) Fried Criteria: consists of five components: unintentional weight loss, weakness, exhaustion (low energy level), slowness (slow gait) and low physical activity. This is operationalised through self-reported questions and non-invasive tests like grip strength using eforto® and timed 4-meter walking. Frailty is defined as having ≥3 of the 5 components, pre-frail participants have 1 or 2 components and robust participants have none of the components. b) Groningen Frailty Indicator: this is a 15-item self-reported questionnaire. Each positive answer is given a score of 1. A score of ≥4 indicates moderate to severe frailty. | 6 months | 
| The correlation between self-perceived fatigue and frailty status. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The Multidimensional Fatigue Inventory will be assessed in the context of self-perceived fatigue. The frailty status will be assessed by a) Fried Criteria: consists of 5 components: unintentional weight loss, weakness, exhaustion (low energy level), slowness (slow gait) and low physical activity. This is operationalised through self-reported questions and non-invasive tests. Frailty = having ≥3 of the 5 components, pre-frail = having 1 or 2 components and robust = having none of the components. b) Groningen Frailty Indicator: = 15-item self-reported questionnaire. Each positive answer is given a score of 1. A score of ≥4 indicates moderate to severe frailty. | 6 months | 
| The correlation between muscle fatigability and frailty status. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The frailty status will be assessed by the frailty assessments: a) Fried Criteria: consists of five components: unintentional weight loss, weakness, exhaustion (low energy level), slowness (slow gait) and low physical activity. This is operationalised through self-reported questions and non-invasive tests like grip strength using eforto® and timed 4-meter walking. Frailty is defined as having ≥3 of the 5 components, pre-frail participants have 1 or 2 components and robust participants have none of the components. b) Groningen Frailty Indicator: this is a 15-item self-reported questionnaire. Each positive answer is given a score of 1. A score of ≥4 indicates moderate to severe frailty. | 12 months | 
| The correlation between self-perceived fatigue and frailty status. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The Multidimensional Fatigue Inventory will be assessed in the context of self-perceived fatigue. The frailty status will be assessed by a) Fried Criteria: consists of 5 components: unintentional weight loss, weakness, exhaustion (low energy level), slowness (slow gait) and low physical activity. This is operationalised through self-reported questions and non-invasive tests. Frailty = having ≥3 of the 5 components, pre-frail = having 1 or 2 components and robust = having none of the components. b) Groningen Frailty Indicator: = 15-item self-reported questionnaire. Each positive answer is given a score of 1. A score of ≥4 indicates moderate to severe frailty. | 12 months | 
| The correlation between muscle fatigability and functional independency. | Muscle fatigability will be measured with the eforto® system (grip work, expressed in kPa*s). The functional independency will be assessed by the Katz Basic Activities of Daily Living (range of score: 6-24; a low score = high function, independent and a high score = low function, dependent) and the Lawton Instrumental Activities of Daily Living Scale (range of score: 9-27; a low score = low function, dependent and a high score = high function, independent). | At baseline | 
| The correlation between self-perceived fatigue and functional independency. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The functional independency will be assessed by the Katz Basic Activities of Daily Living (range of score: 6-24; a low score = high function, independent and a high score = low function, dependent) and the Lawton Instrumental Activities of Daily Living Scale (range of score: 9-27; a low score = low function, dependent and a high score = high function, independent). | At baseline | 
| The correlation between muscle fatigability and functional independency. | Muscle fatigability will be measured with the eforto® system (grip work, expressed in kPa*s). The functional independency will be assessed by the Katz Basic Activities of Daily Living (range of score: 6-24; a low score = high function, independent and a high score = low function, dependent) and the Lawton Instrumental Activities of Daily Living Scale (range of score: 9-27; a low score = low function, dependent and a high score = high function, independent). | 6 months | 
| The correlation between self-perceived fatigue and functional independency. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The functional independency will be assessed by the Katz Basic Activities of Daily Living (range of score: 6-24; a low score = high function, independent and a high score = low function, dependent) and the Lawton Instrumental Activities of Daily Living Scale (range of score: 9-27; a low score = low function, dependent and a high score = high function, independent). | 6 months | 
| The correlation between muscle fatigability and functional independency. | Muscle fatigability will be measured with the eforto® system (grip work, expressed in kPa*s). The functional independency will be assessed by the Katz Basic Activities of Daily Living (range of score: 6-24; a low score = high function, independent and a high score = low function, dependent) and the Lawton Instrumental Activities of Daily Living Scale (range of score: 9-27; a low score = low function, dependent and a high score = high function, independent). | 12 months | 
| The correlation between self-perceived fatigue and functional independency. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The functional independency will be assessed by the Katz Basic Activities of Daily Living (range of score: 6-24; a low score = high function, independent and a high score = low function, dependent) and the Lawton Instrumental Activities of Daily Living Scale (range of score: 9-27; a low score = low function, dependent and a high score = high function, independent). | 12 months | 
| The correlation between muscle fatigability and quality of life. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The quality of life will be assessed by the self-reported questionnaires SarQol (short form), Eq-5D-5L, and Brief Resilience Scale. | At baseline | 
| The correlation between self-perceived fatigue and quality of life. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The quality of life will be assessed by the self-reported questionnaires SarQol (short form), Eq-5D-5L, and Brief Resilience Scale. | At baseline | 
| The correlation between muscle fatigability and quality of life. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The quality of life will be assessed by the self-reported questionnaires SarQol (short form), Eq-5D-5L, and Brief Resilience Scale. | 6 months | 
| The correlation between self-perceived fatigue and quality of life. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The quality of life will be assessed by the self-reported questionnaires SarQol (short form), Eq-5D-5L, and Brief Resilience Scale. | 6 months | 
| The correlation between muscle fatigability and quality of life. | Muscle fatigability will be measured with the eforto® system (grip work, kPa). The quality of life will be assessed by the self-reported questionnaires SarQol (short form), Eq-5D-5L, and Brief Resilience Scale. | 12 months | 
| The correlation between self-perceived fatigue and quality of life. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The quality of life will be assessed by the self-reported questionnaires SarQol (short form), Eq-5D-5L, and Brief Resilience Scale. | 12 months | 
| The correlation between muscle fatigability and circulating inflammatory biomarkers. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The circulating inflammatory biomarkers will be measured by blood sampling: 1x 3mL serum for determination of hsCRP. Additional 1x 9mL EDTA and 1x 9mL serum tube will be obtained for determination of inflammation-related cyto/chemokines including IL1RA, IL6, IL10, TNFα, MCP1, suPAR and sRAGE. | At baseline | 
| The correlation between muscle fatigability and circulating inflammatory biomarkers. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The circulating inflammatory biomarkers will be measured by blood sampling: 1x 3mL serum for determination of hsCRP. Additional 1x 9mL EDTA and 1x 9mL serum tube will be obtained for determination of inflammation-related cyto/chemokines including IL1RA, IL6, IL10, TNFα, MCP1, suPAR and sRAGE. | 6 months | 
| The correlation between muscle fatigability and circulating inflammatory biomarkers. | Muscle fatigability will be measured with the eforto® system (grip work, kPa*s). The circulating inflammatory biomarkers will be measured by blood sampling: 1x 3mL serum for determination of hsCRP. Additional 1x 9mL EDTA and 1x 9mL serum tube will be obtained for determination of inflammation-related cyto/chemokines including IL1RA, IL6, IL10, TNFα, MCP1, suPAR and sRAGE. | 12 months | 
| The correlation between self-perceived fatigue and circulating inflammatory biomarkers. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The circulating inflammatory biomarkers will be measured by blood sampling: 1x 3mL serum for determination of hsCRP. Additional 1x 9mL EDTA and 1x 9mL serum tube will be obtained for determination of inflammation-related cyto/chemokines including IL1RA, IL6, IL10, TNFα, MCP1, suPAR and sRAGE. | At baseline | 
| The correlation between self-perceived fatigue and circulating inflammatory biomarkers. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The circulating inflammatory biomarkers will be measured by blood sampling: 1x 3mL serum for determination of hsCRP. Additional 1x 9mL EDTA and 1x 9mL serum tube will be obtained for determination of inflammation-related cyto/chemokines including IL1RA, IL6, IL10, TNFα, MCP1, suPAR and sRAGE. | 6 months | 
| The correlation between self-perceived fatigue and circulating inflammatory biomarkers. | Self-perceived fatigue will be measured with the eforto® system (2 self-perceived fatigue questions: Question 1: How fatigued are you feeling at this moment? Options for answer: 1-7. 1 is 'not tired', 7 is 'extremely tired'. Question 2: I fatigue quickly. Options for answer: 1-7. 1 is 'No, I don't agree', 7 is 'Yes, I agree'). The participants will also complete the Multidimensional Fatigue Inventory in the context of self-perceived fatigue (also embedded in the eforto® system). The circulating inflammatory biomarkers will be measured by blood sampling: 1x 3mL serum for determination of hsCRP. Additional 1x 9mL EDTA and 1x 9mL serum tube will be obtained for determination of inflammation-related cyto/chemokines including IL1RA, IL6, IL10, TNFα, MCP1, suPAR and sRAGE. | 12 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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muscle fatigability, self-monitoring, prevention, self-perceived fatigue