As one of the fastest sports in the world, the agility component of badminton is crucial in maximising performance. Agility involves two components, the perceptual and decision making component and the physical change of direction (COD) component. COD assessments most often include a single temporal measure, which provides a measure of the COD ability that in most cases inadequately informs programming for COD enhancement in badminton athletes. As an alternative, the multi-faceted badminton specific assessment (BSA) battery has been proposed, which includes the following nine measures: height, body mass, leg length, eight site sum of skinfold, frontal split hip flexibility, sagittal split hip flexibility, vertical counter-movement jump (V-CMJ), multi- directional lunge test (MDLT) and multi-directional cyclic COD test (MDCT). The overall purpose of this thesis was to develop a BSA and to establish which measures best predict overall badminton performance. In study one (Chapter 3), the reliability of two newly designed tests (MDLT and MDCT) was assessed. The MDLT (change in the mean = 0.33-6.78%; TE = 0.03-0.11 s; ICC = 0.55-0.96) and MDCT (change in the mean = 0.12-5.87%; TE = 0.05-0.20 s; ICC = 0.57-0.98) were confirmed to be reliable. In study two (Chapter 4), the purpose was to establish which components of the BSA best predict COD and overall performance in badminton. The best predictors of COD performance were the MDLT (female – r = 0.58; male – r = 0.57), frontal split hip flexibility (F – r = -0.72, M – r = -0.36), eight site sum of skinfold (F – r = 0.65) and V-CMJ (M – r = - 0.49). The BSA was most effective in predicting badminton ability in female athletes; specifically the MDLT (r = 0.59), height (r = 0.51) and V-CMJ (r = -0.48). These findings suggest that the following BSA measures may be utilised to effectively assess the following anthropometric characteristics and performance qualities in badminton athletes: height, leg length, eight site sum of skinfold, frontal split hip flexibility, V-CMJ, MDLT and MDCT. The MDLT may also be replaced by a single forward lunge to assess horizontal neuromuscular capability based on the very large to near perfect correlations (r > 0.75, p < 0.001) between all MDLT directions. To further enhance the diagnostic potential of the MDCT, four consecutive cycles in a single direction may be implemented to better utilise elastic energy of the stretch shorten cycle and mimic the repetitive COD nature of badminton.