The over/unders in the Sweet Spot Base plans are threshold workouts that build your muscular endurance and ability to clear lactate, so sprint workouts would not address the same goal. Depressingly, the only way to get better at over/unders is to keep doing over/unders.
Some possibilities for you going forward:
- Lots of the workouts have less intense variants, and there are lots of similar workouts in the catalog (search for ‘over-under’ and ‘criss-cross’). Find an over/under workout that looks more achievable – shorter intervals, fewer intervals, longer rests between intervals, lower power, etc. – so you can dial down whatever is making you struggle.
- Short backspins during “recovery” intervals can be life-saving, and it’s way better to take a 15-second backspin early than to completely bail later on.
- You can always drop the power during a workout using the “Intensity” controls. If you’re cracking at 100%, try 97%.
Remember that the power zones derived from FTP tests (of any kind, ramp or 8-minute or 20-minute or 40-minute or whatever) are an approximation. The training tools we use make everything seem precise and clinical, but really it’s a giant daisy chain of estimates. Maybe your FTP is spot on; maybe it’s set just too high enough that over/unders are unreasonable. Trust the process, but be flexible with the details.