prestretch

Prestretch, or pre-stretch, is a term used across disciplines to describe applying controlled stretch to a material, tissue, or structure before its use or testing in order to influence how it behaves under subsequent loads.

In biomechanics and exercise science, prestretch refers to lengthening a muscle–tendon unit just prior to a shortening contraction. This eccentric action stores elastic energy and stimulates additional neural activation, contributing to greater force and power in the following concentric movement. The effect is a key component of the stretch-shortening cycle and is evident in activities such as jumping or plyometric drills. However, improper timing or excessive prestretch can increase injury risk and alter joint loading.

In polymer, film, and textile processing, prestretch describes extending a sheet, film, or fiber during manufacture or handling to create an oriented, more stable structure. Pre-stretched films used for pallet wrapping often exhibit higher tensile strength, improved cling, and better load retention, with reduced sag during use. In fibers and fabrics, prestretching aligns polymer chains, enhancing dimensional stability, stiffness, and sometimes resistance to shrinkage after finishing. Premature or uneven prestretch can introduce defects or residual stresses if not controlled.

Prestretch is also applied in textile finishing and elastomeric materials to improve shape retention and reduce post-processing shrinkage. In broader engineering contexts, related ideas include pre-stress practices that modify subsequent performance, such as prestressed components in certain applications.

See also: stretch-shortening cycle, pre-stressed materials, prestressed concrete.