Stretching
I found this sports medicine journal article about stretching. My right hamstring is a bit tight — I seem to have about the same range of motion in terms of reaching my toes, but at the cost of a bit more discomfort at the beginning of the stretch — so I probably have to pay greater attention to it before jujitsu.
In any case, the main points of the article are that:
PNF stretching is a two-man stretching technique; a stretching partner may be hard to find at the gym. We do two-man stretches in the dojo once in a while, but not in the PNF sense of having the partner (tori) applying pressure to cause the stretch while the stretcher (uke) is “resisting”. Next time we do two-man stretches, I’ll try to resist first, then relax into it. I can try this with the locks, also, but these tend to put much more stress on the joints than would be comfortable while resisting.