New index for evaluating pedaling techniques using the pedaling efficiency index with gradually increasing load

Purpose: Measuring the pedal force vector during bicycle pedaling has recently become easy, and research have been conducted using mechanical efficiency (the ratio of an effective driving force to total pedaling force); however, the relationships between these forces were not considered. This study aimed to show that the relationship between these forces can be linearly regressed under gradually increasing load conditions and propose that the slope parameter can serve as a new index for evaluating pedaling skills. Methods: Twenty-eight participants performed the experiment in which the load was increased every minute until the maximum load was exerted. Using sensors installed on both bicycle cranks, the pedaling force vector was divided into tangential and radial components to determine the total pedaling and effective driving forces per minute. The maximum load force and efficiency index were calculated. Results: Our results showed a strong linear relationship (coefficient of determination: 0.982, 95% CI 0.909-0.996) between the total pedaling and effective driving force. The slope parameters from this regression exhibited significant correlations (-0.560 and -0.674) with the maximum load force and efficiency index during maximum exertion, respectively. These correlations highlight the slope parameter potential for capturing pedaling characteristics. Conclusions: The slope parameter derived from the linear regression between the total pedaling force and effective driving force reflects individual pedaling characteristics. This parameter stands out as a promising new index for evaluating pedaling motion, offering insights into participant-specific pedaling behaviors. Consequently, this novel index could be instrumental in assessing and analyzing pedaling skills.