Just under two years ago I bought a modern battery-powered self-propelled lawnmower, that's as powerful as any petrol mower of comparable size. for the last 18 months my back and knee conditions meant it was unusable, as I'd only lurch unsteadily to the left while the mower trundled along in a straight line.
Yesterday I forced myself to try it again and despite back and knee pain I was able to use it effectively.