Massachusetts Court Adopts Nike's Positions on Three of Four Flyknit Terms but Holds a Flat Knit Element Must Have Only Flat Knit Edges.

The case so far

According to the order, Nike filed Nike, Inc. v. New Balance Athletics, Inc. in November 2023, alleging that New Balance infringed nine patents involved in its Flyknit footwear technology: U.S. Patents 8,266,749; 8,898,932; 9,060,562; 9,510,636; 9,730,484; 9,907,350; 9,918,511; 9,924,758; and 11,707,105. In August 2024 the court denied New Balance's partial motion to dismiss the claims on the '350, '511, and '758 patents. The court stayed the case in June 2025 pending inter partes review of the '749, '932, '562, '636, '484, and '511 patents. The parties stipulated in August 2025 to dismiss all claims and counterclaims on the '484 patent, which the Patent Trial and Appeal Board had found unpatentable. Nike appealed the Board's separate decision finding the '749 patent unpatentable, then voluntarily terminated that appeal in May 2026, and the parties stipulated to dismiss the '749 claims as well. The court lifted the stay, held a claim construction hearing in September 2026, and construed the four terms still in dispute across the seven remaining patents.

"Article of footwear" excludes socks

The term appears in the '932, '562, '636, '350, '511, and '758 patents. Nike argued that the term's ordinary and customary meaning includes an upper and a sole structure and thus excludes hosiery, stockings, and socks. New Balance proposed any foot covering in the form of shoes, boots, slippers, or hose. The court found that the intrinsic evidence "overwhelmingly supports" Nike, pointing to claim 1 of the '932 and '636 patents, which recites an article of footwear having an upper and a sole structure secured to the upper, and to specification passages describing conventional footwear as having those two primary elements. It held that a summary statement in the since-invalidated '484 patent did not justify a broader reading, and that "may include" language in the abstracts of the '350, '511, and '758 patents and in embodiments of the '562 and '636 patents could not override the specification's description of an article of footwear as including an upper and a sole structure. The court noted that its construction is consistent with the Board's reading of the same term in New Balance's inter partes review of the '749 patent, with Nike, Inc. v. Skechers U.S.A., Inc., No. 23-cv-9346 (C.D. Cal. Dec. 16, 2025), and with Nike, Inc. v. Adidas AG, 812 F.3d 1326 (Fed. Cir. 2016), which the order cites as overruled on other grounds by Aqua Products, Inc. v. Matal, 872 F.3d 1290 (Fed. Cir. 2017).

A flat knit textile element has only flat knit edges

The '350, '511, and '758 patents recite a flat knit textile element whose flat knit edges are not surrounded by textile structure from which the element must be removed. The parties agreed that the term should be construed to mean "a [flat-]knit, textile element that has not been cut from a larger textile web." They split on whether every edge must be flat knit. Nike argued that the element need only have at least two flat knit edges, so that an element with some knit-to-shape edges and some cut edges would still fall within the claims. The court held that New Balance "has the better argument." Relying on Nike v. Adidas, where the Federal Circuit construed identical language in a related patent, U.S. Patent 7,347,011, and on the Skechers construction of the '511 and '758 patents, it construed the term as "a [flat-]knit, textile element that has not been cut from a larger textile web" and is therefore composed of only flat knit edges. The court also rejected Nike's reliance on a specification passage about textile elements removed from a larger textile element, reasoning that the passage describes textile elements generally and that the patents distinguish circular knit elements cut from a larger web from flat knit elements that are knit to shape.

The heel and ankle limitations

Claim 1 of the '350 patent claims an upper for an article of footwear comprising a flat knit textile element having flat knit edges free of surrounding textile structure and a plurality of apertures formed by omitting stitches in a first portion of the flat knit textile element defining a forefoot region of the upper; a non-textile element secured to a second portion of the flat knit textile element defining the heel region of the upper; and one or more strips of non-textile material secured to a third portion of the flat knit textile element on a lateral side of the upper. Claim 9 claims an article of footwear comprising that upper and a sole structure secured to the upper. New Balance argued that the non-textile element must define the heel region. The court adopted Nike's reading, "a non-textile element secured to a second portion of the flat knit textile element that defines the heel region of the upper," because the specification says the textile element forms the heel region. It added that a claim is construed in light of the claim language, not the accused device.

For "ankle part for covering at least a portion of an ankle of the wearer" in claims 11 through 14 of the '932 patent, New Balance sought a construction of "portions of the upper that are intended to cover and extend above the lateral malleolus and the medial malleolus of the wearer." The court gave the term its ordinary and customary meaning, noting that the claim does not use the words "intended" or "extend" and that the specification's reference to "many" configurations does not limit the claim.

What it means

Nike kept the broader readings it sought on the heel and ankle limitations, and the court rejected New Balance's arguments that those constructions were needed because some accused shoes, in New Balance's view, lack the claimed features. Those disputes now turn on the accused products rather than on claim scope. The flat knit ruling runs the other way. On the '350, '511, and '758 patents, the construction excludes a textile element with any edge cut from a larger textile web. The order does not address whether any accused New Balance upper has a cut edge. On that term the order follows the Skechers court's reading of the '511 and '758 patents and applies it to the '350 patent as well.

Practice pointers

Where the Federal Circuit has construed identical claim language in a related patent, a district court may follow it closely even if the appellate construction arose under the broadest reasonable interpretation standard in an IPR appeal. Abstract language that an article "may include" an element, and an example in a summary section, did not broaden a term the specification otherwise ties to that element. And arguments that a construction is needed to exclude an accused product drew a direct rejection here, so construction briefing tends to land better when it is grounded in the claim language and specification.

What to watch next

Watch for the post-construction schedule and whether New Balance moves for summary judgment of noninfringement on the '350, '511, and '758 patents under the flat knit construction. Also watch the parallel Nike v. Skechers case in the Central District of California, which the court cited for the same constructions.