This document discusses ergonomics in the construction industry. It states that back injuries from improper lifting and positioning cost an average of $30,000 per case, and are a major cost for construction companies. It also notes that injury rates for backs are over twice as high in construction as in general industry. The document outlines how ergonomics aims to reduce injuries by fitting tasks to workers rather than forcing workers to adapt to tasks. It discusses common injuries from repetitive motions and improper postures, and provides principles for safer tool use, materials handling, and workplace design to help prevent cumulative injuries to muscles and joints.