Engineering lecturers report difficulties with student learning of concepts and skills associated with the solution of typical basic mechanics problems. The use of both force and moment equilibrium concepts on free-bodies are basic to all mechanics problems. Despite this it apparently remains a difficult area for a significant number of students, even in later years of their degree. An evidence-based approach has been used to analyse two of the suggested reasons for such difficulties. Both quantitative and qualitative methods have been utilised to establish the role of a student's academic history, and the role of gaps in the student's problem analysis process. Theoretical frameworks were also applied, particularly experiential learning, and an application of the van Hiele taxonomy of geometric reasoning. The results of the application of these frameworks were measured through student survey and students' performance on assessment tasks. Indications are that academic history may not be a good predictor of a student's ability to learn the concepts and skills required. This suggests the need to target specific gaps in their basic maths skills and in their analysis process, and to target our teaching approach to those gaps.