Published: Dec. 5, 2006

Planning a ski vacation this winter but worried you are running out of time to get into decent shape before you hit the slopes?

A University of Colorado at Boulder expert says it can be done and all it takes is one hour of exercise per day, three to four days a week.

"If somebody could commit three to four hours a week doing specific exercises they'll be in good enough shape for the Christmas break," said Daniel Weinberger, CU-Boulder's assistant Nordic ski and fitness coach. "They'll be able to ski around the cross-country course or ski down the hill and enjoy their vacation."

Weinberger's first advice is for people to find an exercise that they enjoy such as mountain biking, jogging, swimming or brisk walking.

"Do the exercises that you enjoy doing and keep it fun, that way it is easier to stay motivated and to stay in shape," he said.

He recommends that people alternate their workout sessions between moderate aerobic exercise, resistance work and anaerobic interval training.

For aerobic exercise:

o Warm up at least 15 minutes.

o Keep your heart rate low and steady throughout the exercise.

Interval training can be done inside on different exercise machines such as a StairMaster, stationary bicycle, treadmill, rowing machine or outside on roller blades, skate skis or a bicycle, said Weinberger.

For interval training, he advises people to:

o Warm up for 15 minutes.

o After warming up, increase the resistance if you are on an indoor machine or, if you are outside, pedal, walk or run faster until it is difficult to continue.

o Stay at this level for four minutes and keep a steady pace throughout.

o After four minutes, slow down and lower the resistance until you are fully recovered.

o Repeat these steps three more times for each interval training session.

According to Weinberger, interval workouts increase stamina and help your body recover quickly from heavy exertion.

For resistance training, he recommends lifting weights. But if you don't have weights or access to a health club there are some exercises you can do at your home or office.

"We utilize the large rubber exercise balls and we do a tremendous amount of core work on those," said Weinberger. "You can do any variety of exercises such as sit-ups, back raisers or push-ups that will help you gain strength."

Another home resistance training exercise Weinberger recommends is the triceps dip.

"What you want to do is get two chairs and, with your back to one chair, put your hands on the front edge of that chair with your arms close to your body, stretch your legs out, put your feet on the other chair and then lower yourself down until your arms are bent at a 90-degree angle and then push back up," said Weinberger.

He recommends doing three to four sets of dips -- 25 to 30 repetitions for each set. And after each hourlong exercise session, take some time to stretch to increase your flexibility.

This combination of training techniques will allow people to Nordic and alpine ski harder, longer with less effort and less chance of injury, Weinberger said.