Core Engagement and Running
Elisabeth Scott explains that runners do not need to actively engage their core muscles while running, as the muscles naturally respond and contract based on the demands of the stride. Engaging the core can actually cause problems such as restricting the natural movement of the diaphragm and resulting in side stitches. A strong core is important for maintaining upright posture while running and can contribute to overall energy expenditure.In this clip
From this podcast

The Running Explained Podcast
s2/e22 "Bad Running Advice" with Coach Elisabeth
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