Shrinkage and Fabric Growth Solutions for Running Shorts: Sample to Bulk Timeline
A realistic plan for developing running shorts with shrinkage and fabric growth solved, from first sample to repeat bulk.
Stage one: definition
Fix under 3% in length and 4% in width after five washes and the construction route. This is where most delays originate, because unclear targets cause repeat sampling. Because high cadence movement plus perspiration at the waistband, target checks are made on a worn sample rather than flat fabric alone.
Stage two: laboratory sample
Request lab dips and a first fabric sample. Confirm against AATCC 135 dimensional change before cutting, then cut 3-5 pieces for fit. Keep AATCC 135 dimensional change named in the tech pack so every lot is measured the same way.
Stage three: wear trial
dimensions change after washing or hanging appears during use. Run a two-week trial with road, trail and track training participants before approving bulk. Where running shorts is worn for road, trail and track training, set tolerances around that range of movement.
Stage four: pre-production
Produce 30-50 pieces from bulk materials. This exposes process variation that a hand-made sample hides. Any change to lightweight woven or knit body with a knit liner requires re-testing against under 3% in length and 4% in width after five washes before bulk is released.
Stage five: repeat orders
Once approved, keep the recipe and report set together so the next order can be released without redevelopment. Past reports from AATCC 135 dimensional change help the mill reproduce the same recipe on the next order.
