Figure 1.
The polar moment of inertia of a tennis racket.
Figure 2.
Convention for dynamic measurements.
Figure 3.
Principal Component 1 (PC1)/Principal Component 2 (PC2) axis system diagram of the peak shoulder extension (E_)/flexion (F_) normalized moments (black markers) during the cocking (C), forward swing (FS) and follow-through (FT) phases.
PC1 explains 54% of the dataset variance and PC2 17%. The individuals are represented by grey markers with PX_IL and PX_IH (X ranged from 1 to 8 according to each player), and the supplementary individuals, summarizing the behavior of IL and IH, are represented by white markers, IL being the racket with a low polar moment of inertia and IH the racket with a high polar moment of inertia. The arrow indicates the main orientation from IL to IH.
Table 1.
Mean (± Standard Error) peak shoulder, elbow and wrist normalized moments (Nm) for rackets with low (IL) and high (IH) polar moment of inertia during the three phases of the tennis serve, with * for significant difference at p≤0.05, and ** for significant difference at p≤0.01.
Table 2.
Mean (± Standard Error) shoulder, elbow and wrist normalized positive and negative powers (W) for rackets with low (IL) and high (IH) polar moment of inertia during the three phases of the tennis serve, with * for significant difference at p≤0.05, and ** for significant difference at p≤0.01.