| 摘要 |
<p>A ball (1) for practicing a sport or game comprises a shell (3) containing inertia means, for example a fluid (9) and a core (7) freely rotatable within the shell. The inertia means exagerates or amplifies the effect of an impact or stroke. Preferably, the core is in the form of an inner ball with a central spindle (11) with a weighted portion (15) at one end. One or more smaller solids loose within the shell can also be used instead of the core.</p> |
