Polymer microstructure effects on impact response, frequency dynamics, and vibrational signatures in high-performance badminton racket strings

Despite substantial research on badminton equipment performance, limited quantitative analysis exists linking polymer string microstructure to player-specific performance outcomes. This study investigated the mechanical behavior of three Yonex BG series multifilament strings: BG66-Ultimax, BG65, and nylon/Vectran®-core BG80—to evaluate potential suitability for offensive playing styles. High-precision accelerometry was employed to measure impact dynamics across three distances (3, 5, and 8 feet) and three string-bed zones (top, center, bottom). MATLAB-based signal processing characterized acceleration patterns, frequency responses via Fast Fourier Transform, and viscoelastic behavior through Hilbert transform analysis and settling time calculations. Statistical analysis found significant differences in peak acceleration among string types (Kruskal-Wallis H = 17.15, p < 0.001, ε² = 0.18). BG66-Ultimax exhibited dominant elastic behavior with mean peak accelerations ~ three times greater than BG65 (17.47 ± 16.55 g vs. 6.04 ± 5.09 g), consistent with rapid energy return, and consistent power generation across impact zones. BG65 demonstrated pronounced viscoelastic damping with gradual decay patterns, providing characteristics associated with control-oriented play at the expense of power efficiency. BG80 displayed balanced intermediate characteristics. While descriptive settling time data showed BG66-Ultimax with shorter mean settling times (0.636 ± 0.632 s) compared to BG65 (0.998 ± 0.753 s), this difference was not statistically significant (p = 0.298). These findings establish a quantitative framework that potentially links polymer microstructure to performance metrics and evidence-based string selection for attacking players. The analytical methods developed may be extended to vibration characterization studies in other racket sports.