One exercise that I'm going to go on record at this point as saying has potential to be more harmful than helpful is the Nordic or Bodyweight Hamstring Curl. Yes, this exercise is hugely popular, but what's the potential negative return for your investment?
We should be asking about the potential for stress placed on the patella during the movement? Is this pathological in some cases? How about forced placed directly down on the Achilles to stabilize the tibia and fibula to correctly perform? Should we not be examining this before implementing?
Personally, I would say there are better exercises. One of my favorite pairs is the TRX Hamstring Curl and Hip Press. I like to alternate these within training sessions and they are powerfully engaging. If you've not yet tried these two movements, you'll quickly see what I mean if you give them a go. I feel more joint-friendly alternatives to the Nordic Hamstring Curl.