1. Department of Nursing, University of Extremadura, 10600 Plasencia, Spain
2. Faculty of Nursing and Physiotherapy, Universidad de Salamanca, 37007 Salamanca, Spain
3. Instituto de Investigación Biomédica de Salamanca (IBSAL), 37007 Salamanca, Spain
4. Department of Nursing and Physiotherapy, Faculty of Nursing and Physiotherapy, Universidad de León, 24401 León, Spain
5. Institute of Biomedicine (BIOMED), University of Leon, 24071 León, Spain
6. Physiology Department, University of the Basque Country, 48940 Leioa, Spain
7. Primary Care Research Unit of Salamanca (APISAL), 37005 Salamanca, Spain
8. University Hospital of Salamanca, 37007 Salamanca, Spain
9. Health Service of Castilla y Leon (SACyL), 47007 Valladolid, Spain