the weight i need to lose is generally fat (stored on my abs), mainly to take some of the pressure off of my joints. I'm not obese or massively overweight but would be in much better shape if i could lose another stone maybe.

Have been training in the gym but have reached the stage where my joints, in particular my right hip joint starts to ache and throb before i have a chance to have a good workout. hence wanting to make my workouts as efficient as possible?

maybe i am doing the wrong sort of workout? are cross trainers, bikes and treadmills the right things to do, if so is one better than the other or should i do weights as well?

also doing some swimming, is this gonna help lose weight, or build muscle?