Nike’s efforts to revive a wearable technology patent have come to an end after the US Court of Appeals for the Federal Circuit summarily affirmed a Patent Trial and Appeal Board (PTAB) decision finding every challenged claim of the patent unpatentable.
In a Rule 36 judgment issued in Nike, Inc. v. Lululemon Athletica Canada Inc. and Lululemon USA Inc., the Federal Circuit affirmed the PTAB’s Final Written Decision in inter partes review (IPR2023-00438) without issuing a written opinion. As a result, the Board’s determination that all challenged claims of US Patent No. 8,620,413 are unpatentable remains in place.
The ‘413 patent relates to portable fitness electronics that calculate and monitor heart-rate exercise zones. During the inter partes review, the PTAB considered the meaning of the claim term “level of physical fitness,” which proved central to the validity analysis.
Nike argued that the term should be interpreted narrowly, contending that it referred only to a user’s cardiovascular fitness. The PTAB rejected that argument, concluding that the claim language and specification did not support such a restrictive construction. Instead, the Board determined that a person’s “level of physical fitness” could reasonably encompass a broader range of physical characteristics, including factors such as stride length and body weight. Applying that broader interpretation, the PTAB found that the challenged claims were unpatentable in view of the prior art.
The Federal Circuit’s Rule 36 affirmance leaves that outcome undisturbed but does not endorse or expand upon the PTAB’s reasoning in a written opinion.
Although the appellate court provided no substantive analysis, the case nevertheless offers useful drafting lessons for applicants developing patents in the wearable technology and digital health sectors. Patent applicants often seek broad claim language to maximize commercial protection across evolving products and future implementations. However, broader terminology can also widen the universe of relevant prior art that may later be applied in validity challenges.
The dispute illustrates the importance of carefully defining key technical terms where a particular meaning is intended. Without an express definition or a clear disclaimer in the specification, broadly drafted claim language may be interpreted more expansively during PTAB proceedings, potentially exposing claims to prior-art references that might otherwise have been distinguishable.
For innovators in personalized health, wearable devices, and fitness-tracking technologies, the outcome serves as a reminder that claim breadth remains a strategic balancing exercise. While expansive language may provide greater commercial flexibility, it can also increase vulnerability during post-grant proceedings if the specification does not clearly support the intended scope of protection.
The Federal Circuit’s decision brings the appeal to a close, preserving Lululemon’s complete victory before the PTAB and reinforcing the significance of claim drafting in an increasingly competitive wearable technology landscape.

Written by Elizabeth Jordan
Senior Industry Engagement Manager, CTC Legal Media
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