The SAVE project is a four arm, randomized-controlled study. The units of analysis will be individual apprentices. However, the units from which the apprentices will be recruited are apprenticeship training centers, with clusters of apprentices within centers assigned at random to one study arm, resulting in a cluster randomized-controlled trial design. Training centers will be randomly assigned to one of four groups: 1) ergonomic training alone, 2) safety voice training alone, 3) combined ergonomic and safety voice training, or 4) control group with no additional training intervention (Table 1).