Primary headaches belong to the most prevalent conditions, leading to pain and disability in the general population and especially in office workers (OW). In a Swiss survey in 2010, a monthly prevalence of 35% in OW has been demonstrated.The Swiss National Foundation has approved a study coordinated by ZHAW to address the issue of neck pain in OW (SNF: 32003B_182389/1). The interventional project is called “Neck exercise for productivity” (NEXPro)”. The aim of the NEXPro-project is to examine the effect of a combined programme, consisting of exercise, health promotion and ergonomics on the productivity and further neck pain related outcomes in 105 Swiss OW. A stepped wedge cluster randomised controlled trial with three participating private and public companies is going to be conducted.Even though representing a significant burden, headache and functions related to headache will not be covered by the NEXPro trial and are therefore part of the current application.Aims of the PhD projects are:1. To establish reliability of physical performance test for headache and neck pain conditions2. To determine the predictive validity of physical performance tests and online screening on headache conditions in the long run.3. To examine the effect of the NEXPro intervention on headache and related outcomes.At Baseline of the NEXPro trial, an online survey and a physical examination, including upper cervical mobility, cervical muscle endurance tests and pain pressure threshold measurements are planned to be performed.Headache outcomes will be collected at four, eight and 12 months follow-up via online questionnaire (short-form headache impact test) and a re-assessment of strength, endurance and pain pressure threshold will be performed.Prevalence indexes for headache with its different types will be calculated.Cox proportional hazard models for headache occurrence and linear mixed models for the other outcomes will be established.