The Missing Link in Running Injury Research: Nonrunning Physical Activity.

Overuse injuries from running occur when the loading stimulus exceeds the tissue-specific loading capacity. Excessive running exposure (training errors) are important precursors to injury. Despite the intuitive relationship between loading, running volume, and injury, a definitive loading exposure that can reliably differentiate between injured and uninjured groups remains elusive. We propose that a singular focus on running-related factors such as gait, running surface change, sudden change in running volume, frequency of running, and acute-to-chronic workload make it difficult to identify reliable mechanisms of loadrelated running injury. Given that the accumulated loading from nonrunning exercise and physical activities of daily living can impose substantial and consequential load on the musculoskeletal system, we make the case for considering loading from all sources of physical activity as a contributor to running injury. .