Alan Birchall spent more than two years designing and making most of the parts for his Pièce d’Essai. Now he is working on a watch for a customer.

Ilia Malinin silenced any doubters of the self-styled “Quad God” on Tuesday, when the American wunderkind threw down a near-perfect short program.

Jerry Lu’s technology demystifies winter sports by tracking athletes’ speed, jumps, and rotations. Part of a figure skater’s job is to make their routine look as effortless and graceful as possible, ...