After increasing resistance to moderately heavy during sprints on a flat, what is the first step?

When engaging in sprints on a flat surface after increasing the bike's resistance to a moderately heavy level, the natural progression is to lift out of the saddle. This position allows for greater force exertion during the sprinting phase. By standing up, the instructor can recruit larger muscle groups, particularly the quadriceps and glutes, which can generate more power compared to pedaling while seated.

Lifting out of the saddle also helps to maintain balance and control of the bike while the increased resistance is applied. This technique is essential during high-intensity efforts because it allows for a more aggressive and powerful sprint, utilizing the rider's body weight efficiently.

Other options may not provide the same level of power or effectiveness needed during this phase of spinning. For example, lowering into the saddle would restrict movement and reduce the ability to generate maximum force. Pushing down hard while remaining seated can lead to fatigue and ineffective energy transfer, while simply increasing cadence without the forward-leaning body position and upward lift wouldn't harness the full potential of the increased resistance. Thus, lifting out of the saddle is the most appropriate immediate action.