In a five-year intervention study about the impact of pre-operative mobilisation training session of patients receiving an elective medial laparotomy experiences about the collaboration between practice (University Hospital Ulm) and science (Hessian Institute of Nursing Research) were made. During the project possibilities and borders of clinical nursing research became clear. A research question based on practice experiences of nurses helps to develop and maintain motivation to conduct a study at a nursing unit. There was a lack of nursing knowledge to develop the best possible design, e.g. outcome criteria for mobilisation and standardized assessment instruments. The cooperation with other health care professionals (human movement science, statistics) was important and without difficulties. In Germany, without doctors' agreement and common application it is impossible to conduct nursing intervention studies in hospitals. It is necessary to train nursing specialists with both scientific and clinical competence to explore systematically clinical research questions.