Condition category
Not Applicable
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status

Plain English Summary

Background and study aims
Currently, occupational health has mainly focused on reducing work-related harm and injury and the risk of work-related sickness and absenteeism, for instance by reducing high physical work demands. However, this approach is not able to adequately address some of the main current challenges in working life and occupational health, for example, musculoskeletal (bone, joint and muscle) disorders and social inequality in health and physical capacity. Some initiatives have attempted to improve health and physical capacity of workers by offering physical exercise at the workplace. However, these initiatives have had difficulty reaching the employees in most need and in being sustained over time. One major reason for this is that the initiatives require time away from performing productive work and are therefore additional to the work required.
The Goldilocks work principle aims to design productive work in a way that promotes health and physical capacity without reducing work productivity. However, the effectiveness of Goldilocks work principle has not yet been tested in workplace settings. The aim of this study is to develop, implement, and evaluate Goldilocks-games, a way of working in childcare that follows the Goldilocks work principle, to promote physical capacity and health among childcare workers, without compromising work productivity.

Who can participate?
Childcare workers employed in the participating childcare institutions during the intervention period.

What does the study involve?
The participants will be asked to answer questionnaires about work and health-related factors, participate in health and physical capacity measurements, and to wear accelerometers and a heart rate monitor for several days. Further, the participants will take part in developing and implementing the Goldilocks games during productive work with the aim of promoting health and physical capacity. Participants will receive the same intervention either immediately following baseline assessments or after a 10-week wait-list period, decided by randomisation at the level of the childcare facility.

What are the possible benefits and risks of participating?
This study will potentially benefit participants by organising their productive work in a way that promotes their physical capacity and health without compromising their work productivity. Still, participation may result in potentially harmful effects from performing moderate to vigorous physical activity, like musculoskeletal pain, work injuries, work stress, increased need for recovery, sickness absence and reduced work productivity, which will be evaluated.

Where is the study run from?
The National Research Centre for the Working Environment (Denmark) and the Work Environment Consultancy of Copenhagen Municipality (Denmark)

When is the study starting and how long is it expected to run for?
January 2019 to December 2021

Who is funding the study?
The Danish Work Environment Research Fund

Who is the main contact?
Andreas Holtermann,

Trial website

Contact information



Primary contact

Prof Andreas Holtermann


Contact details

The National Research Centre for the Working Environment
Lersø Parkallé 105
+45 39165352

Additional identifiers

EudraCT number

Nil known number

Nil known

Protocol/serial number


Study information

Scientific title

Goldilocks Work – Childcare: Can childcare work be designed to promote moderate and vigorous physical activity, cardiorespiratory fitness and health? A randomised controlled trial


Study hypothesis

A participatory organisational intervention in childcare institutions that introduces daily, playful physical activities (termed 'Goldilocks games') together with the children will:
1. Increase work time with health-enhancing moderate to vigorous physical activity (MVPA) during childcare work
2. Improve cardiorespiratory fitness and health among childcare workers

Ethics approval

The National Research Centre for the Working Environment has an institutional agreement with the Danish Data Protection Agency about procedures to treat confidential data (journal number 2015-41-4232), e.g. by securing data at a protected drive with limited access and making all individual data anonymous. The Danish National Committee on Biomedical Research Ethics (the local ethical committee of Frederiksberg and Copenhagen) has evaluated a description of the study and concluded that, according to Danish law as defined in Committee Act § 2 and § 1, the intervention described should not be further reported to the local ethics committee (Ref number: H-18041423)

Study design

Cluster-randomized wait-list-controlled trial

Primary study design


Secondary study design

Cluster randomised trial

Trial setting


Trial type

Quality of life

Patient information sheet

See additional files for information sheet in Danish


Physical activity of childcare workers in the workplace


The intervention aims to increase childcare workers’ productive work time spent in MVPA, and thus their cardiorespiratory fitness and health. Participating childcare institutions will be randomised to either intervention or usual practice (i.e. wait-list control) arms of the trial. This randomisation will be conducted upon enrolment of each participating childcare institution into the study. The randomisation sequence has been developed using the statistical software “R”. Due to the nature of the trial, blinding of participants and those conducting the study will not be possible. However, allocation concealment will be maintained throughout the study, and all researchers involved in the recruitment and enrolment of participating childcare institutions will be blinded to the method used to develop the randomisation sequence. Participating childcare institutions will be informed of their allocation to intervention or usual practice group before the baseline data collection. The reason for randomising prior to the baseline measurement is due to the logistics and feasibility of participating in the intervention.

The participating childcare institutions will be randomly assigned to either the intervention group, which will receive the 10-week intervention immediately after the baseline measurements followed by 10 weeks without further support, or the wait-list control group, which will continue usual practice for 10 weeks while the intervention group receives the intervention and then completes pre-intervention measurements and receives the 10-week intervention.

During the first period, only the intervention group will be offered the intervention, whilst the wait-list control group will be offered already existing ergonomics consultancy and guidance, and advice on musculoskeletal pain management by consultants at the municipality. During the second period, the usual practice group will be offered the intervention, while the intervention group is expected to continue the organisational changes from the intervention without receiving any further intervention delivery. Local municipal work environment consultants (occupational therapists and physiotherapists) will deliver the intervention.

Intervention: The intervention will apply a participatory approach to ensure that the intervention is relevant for, tailored to, closely integrated with pedagogical teaching aims, and feasible for the childcare institutions to implement. The intervention content (Goldilocks-games) has been created on the basis of a continuous dialogue with stakeholders related to childcare (e.g. employer organisations and unions, practitioners in childcare, work environment consultants), observations of childcare work, and dialogue with managers and employees in childcare institutions. Furthermore, the manager, a union representative, and an occupational health and safety representative (collectively referred to as the Trio) from the participating childcare institutions will have a meeting with the work environment consultants. The visit will outline the Goldilocks work principle for the institutions and aim to facilitate planning and management support to the implementation and evaluation of the intervention. The Trio will then be involved in planning and tailoring the intervention process to their own childcare institution. Thus, the Trio is responsible for outlining the pedagogical focus, and rostering and practical planning at their institutions. Involving the Trio at an early stage will enhance the likelihood of organisational buy-in and the possibility for introducing organisational changes.

At each individual childcare institution, the intervention will be initiated by a 2.5-h workshop (Workshop 1) during a regular staff meeting. At Workshop 1, the work environment consultants will inform the participating Trio and childcare workers about the overall concept of the Goldilocks work principle, facilitate the participants to develop tailored Goldilocks-games compliant with their pedagogical teaching goals, and finally facilitate development of specific action plans allocating responsibilities for implementation of the Goldilocks-games in their daily routines and schedules. Information regarding whether the Goldilocks-games were conducted as planned will be collected.

After 3-4 weeks of the intervention period, the work environment consultants will conduct a 1.5-h follow-up workshop (Workshop 2) with the participants at each individual childcare institution. The aims will be to evaluate the implementation of the Goldilocks-games, facilitate sustainability of well-functioning Goldilocks-games, and modify those Goldilocks-games that are not working as intended. Moreover, in order to facilitate implementation of the Goldilocks-games, the work environment consultants will make a consultation visit at the childcare institution 2 weeks following Workshop 1 and a consultation phone call with a member of the Trio 2 weeks after Workshop 2.

Intervention type



Drug names

Primary outcome measure

Work time spent in moderate to vigorous physical activity measured by heart rate (i.e. ≥60% of heart rate reserve) or accelerometers (i.e. fast walking (≥130 steps/ minute), running and stair climbing) between baseline and 10 weeks follow-up

Secondary outcome measures

1. Indirectly measured cardiorespiratory fitness assessed using Ekblom-Bak submaximal cycle ergometer test between baseline and 10 weeks follow-up
2. Resting heart rate during sleep measured by heart rate monitors between baseline and 10 weeks follow-up
3. Need for recovery measured by questionnaire (Need for Recovery-battery) at baseline, 10 weeks and 20 weeks follow-up
4. Self-perceived productivity measured using questionnaire at baseline, 10 weeks and 20 weeks follow-up

All individual level assessments will be completed by all participants at baseline, 10 weeks and 20 weeks follow-up. Participants will receive an electronic questionnaire, which they can fill out during working hours. Assessments of health-related outcomes will include height, weight, waist circumference and resting blood pressure. Assessments of cardiorespiratory fitness measures include cardiorespiratory fitness (using Ekblom-Bak submaximal cycle ergometer test). Physical activities and heart rate will be assessed by accelerometers and heart rate monitors worn over several working days.

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

All employees directly involved in childcare from the recruited institutions who consent to participate in the scientific evaluation

Participant type


Age group




Target number of participants

Number of participants was estimated based on a statistical power analysis of the primary outcome using a clustered parallel group with before-and-after measure to calculate the design effect. The power calculation was based on data from a larger sample (N=167) of childcare workers in Copenhagen in a previous trial (ISRCTN10928313). In this sample, work time spent with a heart rate reserve (HRR) ≥60% was, on average, 1.24 minutes/ day with a standard deviation (SD) between subjects of 2.90. The power calculation was done after processing data according to the principles of a compositional data analysis (CoDA), where work time spent at HRR ≥60% is expressed relative to time spent at HRR <60% using isometric log-ratios. Expressed as an isometric log-ratios, the average relative work time spent at HRR ≥60% was -4.35 (SD=1.10). Based on these transformed data, we will need a total of 112 participants (shared between the intervention and wait-list groups, corresponding to approximately 12 childcare institution clusters) to be able to statistically demonstrate (p<0.05) a 6 minutes/day increase in relative work time spent at HRR ≥60% with a power of 0.80, an estimated intracluster correlation coefficient of 0.05, a fixed cluster size of 10, and an assumed drop-out rate of 30%.

Participant exclusion criteria

1. Pregnant
2. Allergy to tape or tape adhesive
3. Not able to speak or understand Danish
4. Work position ending during the intervention period

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

The National Research Centre for the Working Environment
Lersø Parkallé 105

Trial participating centre

Arbejdsmiljø København
Enghavevej 82

Sponsor information


National Research Centre for the Working Environment

Sponsor details

Lersø Parkallé 105
+45 (0)3916 5200

Sponsor type

Research organisation



Funder type


Funder name

Danish Work Environment Research Fund

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Planned publication in a peer reviewed scientific journal.

IPD sharing statement:
The data sharing plans for the current study are unknown and will be made available at a later date.

Intention to publish date


Participant level data

To be made available at a later date

Basic results (scientific)

Publication list

2020 protocol in (added 24/02/2020)

Publication citations

Additional files

Editorial Notes

09/04/2020: Due to current public health guidance, recruitment for this study has been paused. 24/02/2020: Publication reference added. 10/01/2020: The participant information sheet has been uploaded. 30/12/2019: Trial's existence confirmed by Arbejdstilsynet (Danish Working Environment Authority).