As a follow-up project to the Dyn-Sit-Pain study, this research aims to investigate the overall health as well as the physical and mental well-being through dynamic office chairs. The development of an innovative dynamic office chair concept will be professionally and scientifically supported, and the developed prototypes will be examined within the framework of usability studies.

This clinical trial is a prospective, randomised, controlled, open-label study with two tracks, each in a cross-over design investigating the effect of of two dynamic office chairs (saddle chair with standard pendulum mechanism [Smart Moving Technology], study track 2 = office swivel chair with integrated newly developed pendulum mechanism [Smart Moving Technology New]) on the musculoskeletal system of office workers classified as pain developers.

The study consists of a pre-screening visit and 4 assessment days / visits. After proving eligibility for the study (inclusion/exclusion criteria), subjects are assigned to one of the two study tracks. Subjects are randomised to one of the two study tracks and then to the respective group (Group A to D).

• Study track 1: saddle chair with standard pendulum mechanism (= intervention 1) + static office chair (= control)
• Study track 2: office swivel chair with integrated newly developed pendulum mechanism (= intervention 2) + static office chair (= control).

Depending on the study track and group allocation, the test subjects first receive a dynamic office chair (= intervention) or a static office chair (= control). The randomization will be realized with opaque envelopes in different colours and follows international recommendations.

Overall participants will execute identical assessments. A wash-put period between the control and the intervention phases ensures identical baseline conditions. The overall duration of study participation equals 16 weeks.

Inclusion Criteria:

• Signed Informed consent
• People aged between 18 and 65 years
• People classified as pain developers (e.g.: a 10 mm increase in pain on a 100 mm paper-based VAS)
• Office workers
• Employment status: > 25 h / week
• Sufficient knowledge of German (min. B2 level)
• Body height of at least 160cm required
• Electrically or manually height-adjustable table at main workstation

Exclusion Criteria:

• Physical or mental limitations that make dynamic sitting or use of the procedure chair difficult (e.g. wheelchair users, vestibular dysfunction)
• Pregnancy
• Sitting for less than 20 hours per week at the main workplace
• Body weight over 110 kg and a body height over 195 cm
• Regular therapy or medication for pain or medication that affects the perception of pain (e.g. certain psychotropic drugs according to the package leaflet)
• office chair to which it is not possible to attach the swivel mechanism prototype
• Presence of any chronic disease that may influence pain perception (e.g., chronic kidney disease, fibromyalgia, neuropathy, chronic fatigue syndrome)