Where should jockstrap rear straps sit for comfort?

Short answer: Rear straps are comfortable when they follow the natural crease under the buttocks rather than cutting across the cheek or sliding into the middle. That depends on three things: where the straps join the waistband at the back, where they join the pouch at the front, and how wide and firm the elastic is. Straps that start too close to the centre back tend to slide inward; straps that start too far out cut across the buttocks. Most comfort problems are solved by moving the back anchor points, choosing a wider or softer elastic and setting tension so the straps hold without digging.

Anchor points

• Back: the straps join the waistband on each side of centre back. The distance between them sets the angle of the strap.
• Front: the straps join the base of the pouch. Their position decides how the pouch is pulled back and up, which affects support.
• The line between these points should follow the body crease under the buttocks.

Strap angle and length

Strap length, measured relaxed and stretched, decides how much tension pulls the pouch. Too short and the straps dig in; too long and the pouch loses support and the straps slip. Larger sizes need longer straps and usually wider anchor spacing.

Width and elastic

Wider straps spread pressure and are less likely to roll; narrow straps feel lighter but can cut in. Plush or soft-back elastic is gentler against the skin. Compare elastic tension objectively, for example with a tension and elongation method such as ASTM D4964, so that a change of supplier does not change comfort.

Common problems and fixes

• Straps slide inward: move the back anchor points further apart or reduce tension.
• Straps cut across the buttocks: move anchors closer together or lower.
• Straps roll into a cord: use a wider or firmer-edge elastic.
• Pouch pulled down: increase strap tension slightly or move the front anchor forward.

Testing

Wear-test while walking, sitting, climbing stairs and exercising. Ask testers to mark where straps sit and where they rub. Wash with a recognised domestic procedure such as ISO 6330 and re-test, because elastics can lose tension.

Grading

Grade anchor spacing and strap length using consistent waist and hip measurement points, such as those defined in ISO 8559-1.

Limits

Body shapes differ widely; strap placement that suits most testers will not suit everyone. Offering two strap styles is one way some brands cover more customers.

Facts, recommendations and uncertainty

Established: strap anchor points, angle, width and tension decide comfort and support. Recommendation: adjust anchor spacing and elastic together and wear-test each change. Uncertain: which placement suits most of your customers until tested.

Sources and further reading

• ISO 8559-1:2017 — Size designation of clothes: anthropometric definitions for body measurement
• ASTM D4964 — Tension and elongation of elastic fabrics
• ISO 6330:2021 — Domestic washing and drying procedures for textile testing

Standards and regulations are referenced by their published scope. Test parameters, cycles and pass levels should be agreed with your laboratory for the specific product; legal requirements should be confirmed for each destination market.