The individual pursuit is a 4km cycling time trial performed on a velodrome. The cyclist must choose a pacing strategy to produce the fastest time given his/her physiological constraints. PURPOSE: To improve an energy flow model (de Koning, et. al., 1999, J Sci Med Sport) to account for torque decay and to improve a mechanical model involving forward time integration (Martin, et. al., 2006, Med Sci Sports Exerc.) to better account for track geometry. Combine the two models and determine the optimal pacing strategy for an individual cyclist. METHODS: One cyclist (75 kg, 1.83m, and 32 y/o) was tested to determine mean torque and cadence during 5 sec, and 1, 5, and 20 minute time periods. Subsequently, a power function was fit to the data to relate decay of torque and cadence over time. The second derivative of the torque/time curve was used as the torque decay function (TDF). The cyclist performed a 1 min all-out time trial to quantify the amount of usable anaerobic energy. The cyclist also performed four 2 km intervals at 30, 34, 38, and 41 km/hr on an outdoor, concrete velodrome. A Powertap hub was used to calculate the cyclist's drag coefficient and rolling resistance using multiple linear regression. The cyclist performed a 2km pursuit to calibrate the mechanical model. The energy flow model was modified to include the TDF. The updated model allows anaerobic energy to be used during the acceleration phase with an arbitrary distribution of the rest over time. Peak power (PP, W/kg) and time to constant output (TCO, sec) determined the shape of the power output curve. Power output was then adjusted with the TDF. Combinations of PP (11, 13, 15, 16.6 W/kg) and TCO (0, 7.5, 15, 30, 60, 120) were combined with the mechanical model to calculate 4km times. RESULTS: The combined model predicted pursuit times within 4 seconds (1.1%) of competition times. The optimal pacing strategy involved an acceleration phase with a PP of 11 W/kg and a TCO of 30 sec. The torque decay penalty associated with high initial output (16.6 W/kg and TCA of 120 sec) increased finish time by 23.7 seconds. Results from de Koning (1999) suggested a higher PP and a shorter TCO but they did not take into account torque decay or track geometry. CONCLUSIONS: This research improves upon previous models and accurately demonstrates the effect of different pacing strategies on performance.