Carole Jackson: I am a keen rower but have had some problems with my knees recently that I have been addressing by doing exercises recommended by my osteopath. However, if there is any modification kit available for my Indoor Rower, or if there is anything I could do to modify it myself, I would be pleased to hear about it.Terry O'Neill: There are no modifications as such. There are two things that can be done in the case of rowers with existing knee problems. If you are still receiving treatment you can discuss them with your osteopath as you don't mention what your problem is.The areas of risk for people with knee problems are over compression at the front and pulling the knee joint apart at the finish. The finish position is easier to deal with, especially if it is your own machine. You simply take a small piece of wood and a G clamp. You clamp the wood onto the slide, positioning it at a point so that when your legs are flat the seat wheels touch the wood, stopping its travel. When you row you then lock your knees out against this back stop and you cannot overextend the joint. To address the issue of over compression, you could mount a similar arrangement at the front but you would need to be careful that it did not foul your legs going down. First, although, I would try raising the flexi-foot so that the shin cannot go beyond the vertical.