Let them straighten the leg while pushing against you (gradually) and then beging to let them move. Hopefully, that’s explanatory. You can see it on the GPP download reasonably well I think. I know it’s hard to get an idea of the pressure I use but it isn’t really that much.
At the end of a workout, would you do PNF and static stretching too or would that not be necessary? Thanks.
Depends on the situation. If there is a serious lack of flexibility, you might use static but if there is avarage flexibility, you might consider PNF as I show it. If hamstrings are sore after a session you might use PNF elsewhere and then go with gentle static on that group only.