The design and production of gym and fitness apparel is one of the most technically demanding areas of modern sportswear manufacturing. For sportswear factories supplying gymwear brands, success depends on far more than basic garment construction. Gym and Fitness apparel must perform under high-intensity movement, repeated washing, heavy sweat exposure, and constant stretch, while still delivering consistent fit, opacity, and durability. Products such as sports bras, squat proof leggings, training vests, shorts, cross fit apparel, and performance t shirts all require specialist design input, specific fabric sourcing and stretch garment manufacturing expertise.

Effective gym apparel production starts with understanding how garments perform in real training environments. Fitness clothing must accommodate a wide range of movements including squats, lunges, sprints, lifts, and dynamic functional training typical of cross fit apparel. Unlike casual athleisure, these garments are pushed to their limits during intense workouts and then washed on a regular basis.

The sportswear designer must recognise that stress points vary by garment type. Squat proof leggings are placed under extreme stretch at the seat and thigh, sports bras must manage impact and compression or offer support, while training vests and t shirts need to move freely without twisting or riding up. Shorts must balance mobility with coverage, particularly during compound movements.

Understanding these functional requirements are critical to then informing the factory with key information on fabrics, stitching methods, construction and fit.

Fabrics must be sourced and nominated along with the trims to make sure the performance and quality aligned to the gym goers needs and brand values.

Fabric selection is the foundation of successful gym and fitness apparel. From a factory perspective, it’s important these fabrics are sourced and nominated by the brand or sportswear designer to guarantee performance and quality.

Sweat-wicking and fast-drying properties are non-negotiable. During training, the body generates heat and moisture rapidly, and fabrics must draw sweat away from the skin and disperse it across the surface to evaporate quickly. Poor moisture management leads to discomfort, overheating, and visible sweat patches—common reasons for customer dissatisfaction.

For squat proof leggings, fabric density, yarn quality, knit structure and power of the elastane must be carefully controlled. Stretch alone is not enough; opacity under strain is critical. Designers should source and test fabrics in stretched positions to ensure they remain non-transparent, particularly in lighter colours.

Sports bras require fabrics with controlled stretch in key areas and excellent recovery to maintain support over time. Compression must be balanced with comfort, and moisture-wicking linings are often required. For training vests, shorts, and performance t shirts, lightweight fabrics with mechanical or elastane stretch are typically used to enhance airflow and comfort.

Selecting these fabrics is key to making the kit perform and align with quality and required MOQ’s. Don’t leave this part to the factory. It’s important the brand maintains control of these important aspects that relate to cost, performance and quality.

Gym apparel fit is heavily dependent on precise pattern cutting and engineering. Factories that offer pattern cutting gain a significant advantage when working with emerging and established brands. Gym garments must fit close to the body without restricting movement or causing discomfort during exercise.

It is the job of the designer to create a size specification as part of the Tech pack based on the end users requirements, intended use of the garment and the chosen fabrics that form part of the Tech Pack.

Squat proof leggings require contoured waistbands, shaped hip panels, and seam placement that supports movement without cutting in. Waistband height and tension are critical, particularly for the global market where secure, high-rise fits are in strong demand.

Sports bras involve incredibly complex pattern construction, often combining multiple panels, linings, elastic components, and high support zones. Incorrect pattern grading can quickly lead to inconsistent sizing and high return rates.

For training vests and t shirts, designers and factories must ensure armholes, necklines, and body lengths are optimised for movement and layering. In cross fit apparel, where garments are exposed to high abrasion from equipment, fabric strength and reinforcement zones must be carefully considered.

Stretch garments place additional demands on construction quality. Factories must use appropriate stitch types, thread selection, and machine settings to ensure seams stretch with the fabric without breaking. Flatlock and coverstitch seams are widely used in gym and fitness apparel to reduce chafing and improve durability.

Poor seam construction is one of the most common failure points in sportswear. In shorts, leggings, and sports bras, seam integrity is tested repeatedly during stretching, washing, and wear. A reliable supply partner will carry out seam strength testing and stretch recovery checks as part of internal quality control.

Relaxing the fabric before cutting ensures the size of the garment matches the size specification. Many unqualified factories miss this key point and cut the bulk fabric without relaxation and the garment panels then relax on the factory floor and therefore don’t match the required size specification.

Select a factory that specialises in high stretch garments who understand the specific requirements to produce stretch garments correctly. Many start-ups don’t select the right factory and the goods they receive are often not fit for purpose.