Badminton is the fastest racket sport in the world with smash speeds reaching over 111 m/s (400 kph). This study examined the forehand jump smash in badminton using synchronised force plates and full-body motion capture to quantify contributions to shuttlecock speed through correlations. Nineteen elite male Malaysian badminton players were recorded performing forehand jump smashes with the fastest, most accurate jump smash from each player analysed. The fastest smash by each participant was on average 97 m/s with a peak of 105 m/s. A correlational analysis revealed that a faster smash speed was characterised by a more internally rotated shoulder, a less elevated shoulder, and less extended elbow at contact. The positioning of the arm at contact appears to be critical in developing greater shuttlecock smash speeds. Vertical ground reaction force and rate of force development were not correlated with shuttlecock speed, and further investigation is required as to their importance for performance of the jump smash e.g. greater jump height and shuttle angle. It is recommended that players / coaches focus on not over-extending the elbow or excessively elevating the upper arm at contact when trying to maximise smash speed.

Three-dimensional position data of nineteen elite male Malaysian badminton players performing a series of maximal jump smashes were collected using a motion capture system. A ‘resultant moments’ inverse dynamics analysis was performed on the racket arm joints (shoulder, elbow and wrist). Relationships between racket head speed and peak joint moments were quantified using correlational analyses, inclusive of a Benjamini–Hochberg correction for multiple-hypothesis testing. The racket head centre speed at racket–shuttlecock contact was, on average, 61.2 m/s with a peak of 68.5 m/s which equated to average shuttlecock speeds of 95.2 m/s with a peak of 105.0 m/s. The correlational analysis revealed that a larger shoulder internal rotation moment (r = 0.737), backwards shoulder plane of elevation moment (r = 0.614) and wrist extension moment (r = −0.564) were associated with greater racket head centre speed at racket–shuttlecock contact. Coaches should consider strengthening the musculature associated with shoulder internal rotation, plane of elevation and wrist extension. This work provides a unique analysis of the joint moments of the racket arm during the badminton jump smash performed by an elite population and highlights significant relationships between racket head speed and peak resultant joint moments.

The modified goniometric platform (MGP) is a novel instrument used to measure trunk rotation while sitting. A lack of reliable and valid evidence has been reported to measure trunk rotation using MGP. Therefore, this study was aimed to investigate the intra- and inter-rater reliabilities and validity of the MGP for measuring trunk rotation while sitting. Methods: Seventeen participants performed right trunk rotation followed by left trunk rotation (three repetitions for each trial) and two random measurements at 40-minute intervals. Inter-rater and intra-rater reliabilities were calculated using intraclass correlation coefficients (ICCs). Validity was assessed using the Pearson correlation coefficient (r). Results: The test and re-test inter-rater reliabilities for right trunk rotation were 0.990 and 0.986, respectively, and those for left trunk rotation were 0.989 and 0.978, respectively. The intra-rater reliabilities for right trunk rotation were 0.949 and 0.954, respectively, and those for left trunk rotation were 0.944 and 0.946, respectively. The right and left trunk rotation validities were 0.986 and 0.981, respectively. Conclusion: MGP is reliable and valid for measuring right and left trunk rotations while sitting.