پیش بینی انرژی نیروهای کارآمد پدال در دوچرخه سواری با استفاده از مدل های شبیه سازی عضلانی اسکلتی

A biomechanical simulation model was developed to analyze energy efficient pedal forces in cycling. With a genetic optimisation algorithm muscle activation has been optimized in order to minimize metabolic energy consumption. Results show that the established mechanical definition of the Index of Efficiency is not appropriate to quantify pedaling technique, because it is not in agreement with metabolic efficiency of the biomechanical system.

To improve the transfer of human power to cycling performance, technical solutions such as elliptic chain rings, pedal-crank systems with varying lengths or independent crank arms have been developed. Since the effects of these systems are small [6, 8, 11], the present mechanism with fixed crank length and circular chain rings are most commonly used in cycling. In addition to optimise the equipment it is also possible to improve the athlete’s pedalling technique. The task for athlete is hereby to maximize the motive efficiency, defined as the ratio between propulsive tangential force and the total force applied to the crank shown in Fig. 1.It has been shown that applying optimal oriented forces to the pedal during cycling enhances power output for comparable load magnitudes [4]. However, studies on groups on high performance and recreational cyclists did not show any correlation between power output and Index of Efficiency [3, 7]. Therefore, the purpose of this study was to demonstrate that the above mechanical definition of Index of Efficiency is not in agreement with the metabolic efficiency of the biomechanical system. In particular we want to show that radial forces, even though not being effective for propulsion are important to realize efficient transfer of muscle power to cycling performance.

Considerable radial pedal forces were obtained when muscle activation was optimized for minimal metabolic energy consumption. Consequently IE results in relatively low values in all sectors - except for sector II. It can be concluded that the traditional definition of efficiency of motion, which is based on the reduction of radial forces in all sectors, might not be appropriate to describe pedalling technique properly. Instead it is concluded that for optimal pedalling technique a certain amount of radial pedal force is needed. Further analysis of muscle mechanics contribution to sectors’ work distribution will follow to fully understand the biomechanical explanation of our findings.