Stiffness selection distorts loading–sweating associations

This proposed hypothesis asks whether selecting skin samples with similar final stiffness can make past loading appear to reduce sweat-gland secretion. It matters for restoring skin function in middle-aged people. Final stiffness is tissue resistance after intervention. Past loading and baseline tissue properties influence it. Selecting a narrow range may create selection bias: a false link from sample choice between loading and sweating. The test compares the full randomized sample, adjusted for baseline secretion, with the stiffness-selected subset. Support would require analysis to put the loading effect within a prespecified equivalence margin around zero, while selection produces or changes the association. Baseline secretion and exclusions must be recorded.