Margaret, are you trying to improve flexion? You don't actually say, but I assume that's so.
The way to train to do something better, is to do it. Sorry to restate the obvious, but we lose track sometimes. The only way IMO to improve flexion is to do it; the skateboard stretch that I advocate, or any other kind of stretch that challenges and tries to extend flexion.
I, for instance, am much stronger than a month ago because of 500 miles on the bike, but flexion has slightly worsened due to my lazy neglect of the stretches needed.