In the last week, my right knee has had some issues. When I am pushing fairly hard on the pedals, there will be a twinge of discomfort and a moment of weakness.

The discomfort is a quick, small "ouch" sensation that, if I can describe it this way, feels like it comes from deep inside the knee. It lasts for a fraction of the pedal stroke, like 1/4 second. The weakness is my leg suddenly not pushing for just an instant, almost like a momentary "stagger"; it comes at about 3 o'clock in the pedal revolution. The result is to interrupt the power of the pedal stroke, I complete the stroke but without the peak force that I intended. I'm not sure if I would have the same issue on the next pedal stroke, as when this happens I always back off and stop pushing hard. I think it is usually the right knee, actually I can't recall noticing it ever happen to the left knee.

It happens only when I'm pedaling seated. I'll typically be in 53/17 or 53/21, something like that, about 70 rpm, trying to accelerate (like through an intersection, etc). There is no discomfort or stiffness otherwise, on or off the bike. I have no history of knee issues, other than maybe once or twice a year my knees will get mildly sore for one or two days, which always goes away with a rest, meaning I take it easy on the next few days' rides, spinning a lower gear. That soreness is a different sensation than the momentary twinges I'm noticing now.

I usually ride every day (bike commuter) but didn't hardly ride for about two weeks (snow and ice storm in Portland, then I went to NYC and was stuck there by another snowstorm). Last week was my first back on the bike. I'm just doing my usual quite short commute, but I guess I am re-acclimating to daily riding and maybe that is related to these twinges.

What I am doing about it is, I've changed to riding in lower gears (about two cogs higher) and slowing down a bit - basically, taking it a bit easy. I'm going to be mostly off the bike for most of the next two weeks (business travel - although I guess there are stationary bikes in the hotel gyms). When I get back to daily riding, I will also take it easy for the first week. Then I plan to gradually go back to my usual gearing and pedaling ways.

Make sense? Do you ever get this? What is my knee telling me? When I get the twinge/weakness, should I keep pushing and see if it recurs or stops on the next pedal strokes?

50 y/o. Reasonably fit. No knee injuries. Ride about 2500 miles/yr. Daily short commute plus some weekend rides plus a couple centuries. Typical cadence 70-90 rpm.