Where am I supposed to be sore?

[gvcormac]

I've never been sore anywhere from rowing. If I sprint (e.g. 100m) I can get a burn in my arms, but never legs.

My guess is your problem is grip strength. You might want to try bar hangs, or pull-ups, or those springy wrist exerciser thingies. Ease into pull-ups if you're not used to them. You can get golfer's (climber's) elbow and that takes months to abate.

In the meantime, just row slower. Play with damper setting and stroke rate. Straighten and flex your fingers occasionally during recovery to avoid death grip on handle.

I typically row at about 30 spm. Many people advocate slower, but I'm comfortable at 30. I can do 20 or even 15 at about the same rowing pace, but I prefer 30. Maybe up to 35 in an all-out 10km.