performance determinants of fixed gear cycling during criteriums nowadays fixed gear competitions on outdoor circuits such as criteriums are regularly organized worldwide to date no study has investigated this alternative form of cycling the purpose of the present study was to examine fixed gear performance indexes and to characterize physiological determinants of fixed gear cyclists this study was carried out in two parts part 1 n36 examined correlations between performance indexes obtained during a real fixed gear criterium time trial fastest laps averaged lap time during races fatigue indexes and during a sprint track time trial part 2 n9 examined correlations between the recorded performance indexes and some aerobic and anaerobic performance outputs vo2max maximal aerobic power knee extensor and knee flexor maximal voluntary torque vertical jump height and performance during a modified wingate test results from part 1 indicated significant correlations between fixed gear final performance ie average lap time during the finals and single lap time time trial fastest lap during races and sprint track time trial in addition results from part 2 revealed significant correlations between fixed gear performance and aerobic indicators vo2max and maximal aerobic power however no significant relationship was obtained between fixed gear cycling and anaerobic qualities such as strength similarly to traditional cycling disciplines we concluded that fixed gear cycling is mainly limited by aerobic capacity particularly criteriums final performance however specific skills including technical competency should be considered