The Effects of Bicycle Geometry on Sprint Triathlon Cycling and Running Performance.

Abstract

The purpose of this study was to investigate the effect different bicycle seat tube angles (STA) have on subsequent sprint triathlon cycling and running performance. Ten trained male triathletes (34.8 ± 10.9 years), completed two 20 km time trials on a cycle ergometer, one with an STA of 73° and one with a STA of 81°. This was followed immediately by a 5 km treadmill run. Both were completed as fast as possible. Run time (mm:ss), velocity (m.s^-1), heart rate (Beats.min^-1), oxygen consumption (ml.kg.min^-1), rate of perceived exertion (RPE), power output (W), cadence (Revs.min^-1), cycling velocity and stride length (SL) and stride frequency (SF) were recorded. 5 km run time improved significantly following cycling with the 81° STA compared to 73° STA (27:10 ± 3:09 vs. 27:59 ± 3:18 min respectively; p=.006), along with running velocity (3.13 ± 0.37 vs. 3.04 ± 0.37 m.s^-1 for 81° and 73° respectively; p=.007). Stride length also increased significantly following the cycle time trial with the 81° STA (2.20 ± 0.26 vs. 2.12 ± 0.27 m for 81° and 73° respectively; p=.007). There were no other significant differences found. These results suggest that cycling on a bicycle with a steeper STA improves subsequent running performance during a simulated sprint triathlon, possibly due to increased running economy.