Morton & Callister 2015, Exercise-related transient abdominal pain (ETAP)

Narrative review in Sports Medicine (2015; 45(1):23-35; doi:10.1007/s40279-014-0245-z) of the “side stitch”. Roughly 70% of runners report ETAP in a given year. The pain is sharp or stabbing when severe, cramping or aching when milder, and usually localises to the lateral mid-abdomen. The authors weigh the candidate mechanisms (diaphragmatic ischaemia, gastrointestinal/ligament stress, and irritation of the parietal peritoneum) and conclude that irritation of the parietal peritoneum best fits the features, while stressing the mechanism remains unsettled. Associations include recent eating or drinking (especially hypertonic/concentrated drinks) before exercise and being less trained.