Bicycle seat interface pressure: reliability, validity, and influence of hand position and workload

Bicycle seat pressure is often examined by researchers exploring solutions for reducing seat injuries as it is thought a critical determinant; however, a reliable and valid methodology for this undertaking has not been reported. The current study was designed to address this shortcoming and to establish baseline interface pressure measurements for females and males. Participants completed two separate identical bicycle ergometer trials at 118 W in the tops and drops and at 300±82.4 W in top handlebar positions. Seat pressures were quantified from a pressure-sensing mat and the validity of the pressure system was examined through the relationship between known seat weights and the sum of seat pressures. Within trial intraclass correlation coefficients (ICCs) ranged between 0.90 and 0.99 and the between trial ICC values ranged between 0.02 and 0.96. The relationship (Pearson correlation coefficient) between seat weight and the sum of pressures was 0.97. Significant peak pressures were 39% greater in the 118 W top than 300 W top handlebar condition and 29% greater than the 118 W drop handlebar condition (p<0.05). The gender comparison revealed that significant male peak pressure values were greater (24%) and that female values were less influenced by the hand position factor. Select within trial pressure measurements were found to be reliable during pedaling and valid statically. Additionally, the results indicated that workrate and hand position were factors influencing seat pressure and that males and females responded differently to adjustments of these factors.