Hi Debi L Thanks for the question. I use 2 heavy springs for Knee Stretches on the Gratz reformer. However, it can be a really fun one to play with springs to further challenge your athlete. They'll generally be used to pushing against heavy force, so by reducing the resistance we can increase mindfulness and core connections. If they're doing well with it and have the control element down, I'll even have fun by challenging them to a few reps on a super light spring, or even none at all (brutally tough 😁).
Have a play and let me know if you have further questions, or need an answer more specific to your reformer of choice. 🤙