I am a 48-year-old woman about to go skiing for the first time in 20 years. I jog a bit, for 40 minutes two to three times a week, and am not overweight, but I doubt that's enough and my knees creak. Any suggestions for a quick fix in five weeks?

Increase your cardio sessions to four times a week by keeping up your jogging regime and complementing it with lap swimming or, preferably, brisk hill-walking.

Three times a week after your jog, follow my home ski circuit programme, too. To boost cardiovascular stamina, do two minutes' stepping up and down on a low stair, followed by 30 seconds' skipping: repeat four times. For leg stamina, do 16 pole squats: wrap a towel round a fixed stair banister, firmly grip both ends and step a foot away from the pole, so the towel is taut; keeping your back straight, lower to a squat, hold for three seconds, check you can see your toes, then slowly return to upright.

To improve knee stability, try 12 one-leg wall presses: stand with your back to a wall and place a large resistance ball (from proactive.com) between the wall and the small of your back. Lift one foot off the floor, slowly bending your knees to lower yourself into a squat position; keep pressing the ball into the wall as you squat up and down. For torso tone and stability, do side oblique curls: lie on your back, knees bent, press your knees together and lower them to one side while keeping your upper body facing upwards. Support your head with your hands and slowly lift from the breastbone. Perform eight on one side and then switch legs. Enjoy the slopes.

· Joanna Hall is a fitness expert (joannahall.com). Send your exercise questions to Weekend, 119 Farringdon Road, London EC1R 3ER (weekend@theguardian.com).