How to test the stretch recovery of nylon/spandex sports fabrics?

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Good stretch recovery in nylon/spandex sports fabrics means the material returns to its original shape quickly after repeated extension, without visible bagging or loss of compression. If recovery is weak, garments will deform after wear even if the fabric feels elastic when new.

The first evaluation criterion is extension–recovery ratio under load. Stretch the fabric to 120–130% of its original length for 30 seconds, then release and measure recovery after 1 and 5 minutes. High-quality sports fabric should recover at least 95% within 1 minute. Second, check cyclic fatigue performance by repeating the stretch–release process 5–10 times; recovery loss after multiple cycles indicates poor spandex quality or unstable knitting. Third, assess directional recovery in both warp and weft, since uneven recovery often leads to twisting or seam distortion in finished garments. A fourth criterion is post-wash recovery, tested after at least one heat wash and tumble dry.

A common mistake brands overlook is testing only raw fabric, not dyed or finished fabric. Heat setting, dyeing, and finishing can permanently damage spandex recovery. Always test after full production finishing to avoid bulk-production failures.