The aim of this article is to determinate a biomechanical risk analysis method based on a multi-methodological study for high-buildings under construction. This aim bases on the discussion related to the discrepancies about the risk analysis technique applied due to the differences in terms of risk types and levels of risk that different methods provide. The research analyzes the known musculoskeletal disorders, injuries, damages and the biomechanical risk factors of workers in high-buildings under construction. The data collected covers a sample of 150 workers in a high building under construction in Spain over a 12-months period. The research strategy consists in the following five stages: Firstly, tasks and task groups were identified and classified in five working groups of activities. Secondly, the study applies techniques of direct observation to calculate the level of biomechanical risk. Thirdly, the semi-structured interview conveyed approaches to obtain specific data about signs of Work-Related Musculoskeletal Disorders (WRMSDs). Fourthly, the study discusses the occupational registered injuries by analysis of medical diagnoses. Fifthly, the software tools tested provide more details of direct observation techniques as the traditional forms to calculate the levels of biomechanical risk. The results of the multi-methodological research design illustrate a phased approach may be contrasted between the stages and it allows a more complete analysis in order to compare the results. The research findings indicate that activities in buildings have a strong need to improve the analysis of designing processes in order to determinate tailored tasks and lessening bodily injuries and damages. Keywords: Ergonomics, methodology, Work-related musculoskeletal disorders, activities in buildings