Both sprinters race on a modern synthetic track surface, calibrated to World Athletics specifications. The track is the standard polyurethane composite used at championship venues since the late 1970s, designed for elastic energy return and consistent surface friction across temperature ranges.

Track surface matters less in sprint than many fans assume. The IAAF's biomechanical research on Berlin 2009 found that surface contribution to a 100m time at the elite level is small compared to athlete-specific factors like reaction time, stride length, and top-end velocity. Within the modern synthetic range, surface effects are measured in hundredths of a second.

The track does not favor either runner. Bolt set his world records on this surface. Lewis set his on functionally identical predecessors. The decision to equalize both runners on a modern synthetic track removes surface variability as a confound. What remains is biomechanics, race execution, and the conditions the user selects.

Both runners wear spikes appropriate to their era's design and to their documented preferences.

Usain Bolt raced in Puma spikes throughout his career. By 2009 these incorporated lightweight synthetic materials, embedded pin plates, and ankle support designed around his stride. His shoes were specifically tuned to his 1.95 m frame and his unusually long stride length.

Carl Lewis raced in Nike spikes through most of his career. The Nike Track Spike of his era was lighter than the cleated trainers of the previous generation but did not yet incorporate the carbon-plate technology that would emerge in the 2010s. His shoes were tuned to his 1.88 m frame and his shorter, faster stride frequency.

Modern carbon-plated super-spike technology (introduced in 2020) is excluded from this matchup. Neither runner raced in such shoes during their competitive careers, and including them would distort both profiles. The simulation pairs each runner with the equipment they actually used.

Electronic timing accurate to the thousandth of a second, calibrated to World Athletics standards. Reaction times are measured from the starter's pistol via pressure sensors in the starting blocks. Finishing times are recorded by photo-finish camera systems standard since the late 1980s.

Both runners benefit from the modern timing system. Lewis's earliest world-class races were timed to the hundredth of a second; later in his career, thousandths became standard. Bolt's entire elite career was timed to the thousandth. The simulation harmonises both runners to thousandth-precision timing.

Within this fixed equipment framework, the user controls four variables:

• Distance: 60m or 100m, the two events both runners competed in seriously
• Wind: continuous from strong headwind to strong tailwind, with race-legal and record-legal flags surfaced separately
• Altitude: sea level, Mexico City (2,240 m), or La Paz (3,640 m)
• Athlete form era: four documented career points per runner, allowing users to pit peak Bolt against peak Lewis or compare across eras

The track, the shoes, and the timing system are constants. What changes is the conditions of the race and the form of each runner.