A single piece of sportswear fabric can now be engineered to offer high breathability in the back, high elasticity around the waist, and strong support across the chest — all during one knitting process. This is the core shift brought by KARL MAYER's new RJ 4/2 EL machine.
Technology in Focus: Industrializing Body Mapping
In July 2026, KARL MAYER introduced the RJ 4/2 EL, the latest addition to its RASCHELTRONIC® family. The key upgrade lies in the precision of electronically controlled jacquard guide needles, enabling warp knitting mills to create different loop structures within a single fabric width. This allows zoned elasticity, breathability, and support without post-processing.
Industry data confirms that body mapping design is accelerating in sportswear and premium lingerie. Traditional methods rely on panel stitching, thermal bonding, or finishing coatings — multiple steps with higher defect rates and longer lead times. The RJ 4/2 EL accomplishes zoning directly through knitting, compressing what used to take 3–4 processes into one production cycle.
For buyers, this directly shortens development timelines. A typical body-mapping fabric sample used to take 4–6 weeks; now it can be reduced to under 10 working days. That has a tangible impact on launch schedules for fast-fashion and sports brands.
Category Impact: Lingerie and Athleisure First
According to KARL MAYER's official release, smart lingerie and sporty athleisure designs are the first beneficiaries. The reason is straightforward: these categories have the most rigid demands for elastic and breathable zoning.
Take sports bras as an example. Shoulder straps need high support, the underband requires high elasticity, and the back demands high breathability. Traditional solutions involve stitching panels of different elasticities, which can cause friction discomfort at seams. The RJ 4/2 EL knits a seamless fabric with gradient elasticity across zones, directly improving wear comfort.
Athleisure wear follows the same logic. Yoga pants need high elasticity at the waistband, moderate compression in the thigh area, and breathability in the calf area. One machine producing a full-width zoned fabric simplifies supply chain management for brands, reducing quality risks from multi-step outsourcing.
Dual Rise: Equipment Costs and Process Barriers
For warp knitting mills, adopting the RJ 4/2 EL means recalculating two sets of numbers.
First is depreciation. RASCHELTRONIC® machines are premium-priced, significantly higher than standard models. Mills need to assess whether their order mix can sustain utilization rates. If the customer base is mainly commodity fabrics, the payback period could exceed three years. But for mills already supplying sportswear or premium lingerie, the marginal return is more attractive.
Second is the process barrier. Electronic jacquard guide needle control requires more specialized pattern design and engineering skills. In the past, warp knitting mills hired primarily for machine operation skills. Going forward, they will need technicians who understand both knitting structure design and electronic control. This creates a hidden barrier for smaller mills.
Regional Reactions and Procurement Strategy Shifts
Looking at global warp knitting clusters, Keqiao and Shengze in China, along with mills in Germany and Italy, will be the first to feel the change. Keqiao mills that master body-mapping knitting early could gain pricing power in the sportswear fabric export market.
For brand procurement teams, supplier evaluation criteria need updating. Past assessments focused on capacity, lead time, and price. Now, two new hard metrics should be added: machine model and process development capability. It is recommended that buyers request body-mapping fabric samples during the next round of supplier audits, to gauge whether the mill's technical readiness aligns with product needs over the next 2–3 years.