Competitive badminton players are continually searching for strategies to enhance their performance. Among the recent developments is the spin serve, a technique that involves imparting a pre-spin to the shuttlecock prior to racket contact. This method has proven so effective that some athletes have labeled it as “impossible to return.” Due to its impact, the Badminton World Federation (BWF) imposed a ban on the spin serve in 2023, extending the prohibition until after the 2024 Paralympic Games in Paris.
The BWF’s decision was not intended to stifle innovation; rather, it aimed to address concerns from players regarding the potential advantages the spin serve could provide. The organization felt that major tournaments should not serve as experimental grounds for such a strategy, particularly since the spin serve closely resembles the previously prohibited “Sidek serve.” Earlier this year, the BWF officially banned the spin serve. Recently, Chinese physicists have analyzed the intricate physics underlying the spin serve, with their research being published in the journal Physics of Fluids. More details can be found here.
The structure of shuttlecocks sets them apart from other sports projectiles. Featuring a conical shape, they consist of sixteen overlapping feathers attached to a rounded cork base, which is typically covered in fine leather. For casual play, synthetic nylon birdies might be used, but competitive players generally opt for feathered varieties.
The overlapping feathers significantly increase drag, resulting in rapid deceleration as the shuttlecock travels. Consequently, its parabolic flight path descends at a sharper angle than it ascends. This added drag necessitates considerable force from players to propel a shuttlecock the entire length of a badminton court. Nevertheless, shuttlecocks can reach speeds exceeding 300 mph. The feathered design also imparts a natural spin along its axis, influencing various strokes. For example, executing a slice from right to left typically produces a more effective tumbling net shot.
Chronophotographies of shuttlecocks after an impact with a racket.
Credit:
Caroline Cohen et al., 2015
Additionally, the cork base contributes to the aerodynamic stability of the shuttlecock. Regardless of its initial orientation, the birdie will adjust mid-flight to ensure it travels with the cork end leading and maintains this position throughout its trajectory. A 2015 study focused on this characteristic flip, utilizing high-speed videography and free-fall tests in a water tank to examine how design affects performance. The study concluded that the geometry of the shuttlecock feathers optimally aligns at a specific opening angle that balances performance, confirming that feathered varieties outperform synthetic ones by deforming more effectively upon impact to create a more efficient flight path.
