Was it me ??
Flying solo circuits yesterday (beautiful day) in the club 172, I started my 3rd and was on climb out and pitching up for best rate of climb, trimmed back, and all of a sudden the elevator controls became very heavy, and I mean very heavy. I was pulling back with all my strength and with both hands just to maintain the required rate of assent. I asked for immediate return and the tower was excellent. As I still had a positive rate of climb I did a gentle 15 degree turn and managed to attain circuit hieght (1000ft), called down wind. In level flight there was no problem with the controls, and I was able to make a normal approach and landing.
On return to the club we crawled over the aircraft, elevators fine, full deflection on trim tabs etc. Trouble is I now find that I am trying to convince myself that it must have been me ! and that there wasn't a technical problem. The best I can come up with is that after my second landing the trim tab may have stuck temporarily.
I'd be grateful for any input, so I can stop beating myself up !