I ran a 10K on sat. (11:31 min miles) I've been running in vff for about 3 months following a 4 month bout with tendonitis in my foot. Around mile 5 my right knee started hurting. I injured it 30 years ago (I'm 53) and it has been weak ever since. This is the second time since running in the vff that the knee has hurt. It recovers quickly, about a week. I've decide to transition into bfr. Any suggestions on avoiding knee problems? Should I wear a knee brace while running?