Effects of Seat Tube Angle Manipulation on Cardiorespiratory Response and Frontal Area in Female Cyclists

Abstract

Anecdotal and photographic evidence suggests that female cyclists and triathletes exhibit markedly more upright body positions than their male counterparts when riding in an aerodynamic position, which may, in turn, lead to a decreased performance outcome. Manipulating seat tube angle is a potential mechanism for improving the aerodynamic position in competitive cyclists. PURPOSE: Therefore, the purpose of this study was to investigate the cardiorespiratory and metabolic responses and frontal area when the position on the aerodynamic bicycle was manipulated in trained female cyclists and triathletes. METHODS: The study sample (n = 25) consisted of eight cyclists and 17 triathletes (age = 41.8±10.8 yrs; ht = 167.5±6.4 cm; body mass = 62.3±7.5 kg; body fat = 17.7±3.9%; VO2max = 51.7±9.3 ml·kg-1·min-1). Subjects performed three, 15-minute trials at seat tube angles of 73°, 82°, and self-selected (mean = 76°) at a workload corresponding to 65% of VO2 max and a pedaling rate of 90 rpms. The tests were performed on an adjustable stationary ergometer equipped with forward facing aerodynamic handlebars, and the position for each subject was adjusted to maintain the hip angle across all positions. Oxygen uptake (VO2), minute ventilation (VE), heart rate (HR), blood lactate (LA), rating of perceived exertion (RPE), and frontal area were recorded for each position. RESULTS: VO2 and %VO2max were significantly lower in the 82° position compared to the 73° and self-selected positions (32.9, 34.5 and 33.9 ml·kg-1·min-1; 64.2%, 67.3%, and 65.9%, respectively; p < 0.05). VE was significantly lower at 82° compared to 73° (55.1 and 57.3 L·min-1; p < 0.05). There were no significant differences for HR, RPE, or LA between positions. Frontal area was significantly lower at 82° compared to the 73° and self-selected positions (2424, 2532, 2526 cm2, respectively; p < 0.05). CONCLUSION: In this group of women, the 82° position (i.e., steepest seat tube angle) was the most economical position for oxygen uptake and ventilation, suggesting that during steady state cycling a steep seat tube angle may be the most beneficial position for cardiorespiratory responses and reduced frontal area. This study demonstrated that female cyclists can achieve aggressive aerodynamic positions without compromising cardiorespiratory performance.