Modern Tennis Biomechanics
Most of dynamics in contemporary human biomechanics is autonomous (see [II06a, II06b, II06c, II07e, II07a, II08c, II08b]). This approach works fine for most individual movement simulations and predictions, in which the total human energy dissipations are insignificant. However, if we analyze a 100 m-dash sprinting motion, which is in case of top athletes finished under 10 s, we can recognize a significant slow-down after about 70m in all athletes - despite of their strong intention to finish and win the race, which is an obvious sign of the total energy dissipation. This can be seen, for example, in a current record-braking speed-distance curve of Usain Bolt, the world-record holder with 9.69 s, or in a former record-braking speed-distance curve of Carl Lewis, the former worldrecord holder (and 9 time Olympic gold medalist) with 9.86 s (see Figure 22.1). In other words, the total mechanical energy of a sprinter cannot be conserved even for 10 s. So, if we want to develop a realistic model of intensive human motion that is longer than 7-8 s, we necessarily need to use the more advanced formalism of time-dependent mechanics.
KeywordsTangent Bundle Humanoid Robot Cotangent Bundle Contraction Dynamic Cotangent Space
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