It may not be cold outside, but if you're planning to hit the slopes to ski or engage in a winter sport for your next holiday, then it's vital to start training now. The fitter and better prepared you are means more time on the slopes and less chance of injury. "You want to achieve structural balance in the body," says Jeremy Meyer of Raw Personal Training in Central. "Many people find that one leg is stronger than the other, which may affect their turns, or that certain muscles around the knee joint are weak, which may lead to injury." Common ski injuries include torn anterior cruciate ligament muscles in the knee and hamstring strains. "The aim of training before skiing is to increase the strength of the muscles around the knee, like the vastus medialis [tear drop muscle] and the hamstring, [which flexes the knee], and improve mobility in the ankle and hip joint," says Meyer. Dumbbell split squat (above) Why: to improve mobility in the ankle and hip joint; address muscle weaknesses. Muscles activated: adductor and muscles within the quadriceps. How to: with an upright torso, step forward into a lunge. Lunge through the full range of motion, bending the knee over the ankle, improving mobility. If you have tight ankles and hips, start with front foot elevated. Go down for three seconds, one second on way up. Start with low weight, high repetition and slowly increase weight as strength builds. Single leg lying leg curl (above) Why: develops the knee flexors and hamstrings, also a major knee stabiliser, which tend to be very weak in most people. Muscles activated: the three muscles of the hamstring. How to: lie on front over a leg curl machine and slowly curl single legs. Start with one leg at a time to achieve equal strength before doing two legs at once. Vary the foot position from pointing foot, turning out foot and flexing the ankle. Start with 10 to 12 repetitions per leg, increasing the weight and decreasing repetition range to eight to 10 repetitions after three to four weeks. Front squat (above) Why: this advanced exercise, to be performed once mobility is achieved, is one of the best "core" exercises as you need to keep the spine stable throughout the movement. Muscles activated: all the major muscles of the lower leg, back and core. How to: using a bar (with or without weight), squat through the full range of motion keeping back upright and chest forward. No more than six repetitions on front squats. Variation: heels elevated back squat or cyclist squat. Performing a back squat on a small step helps activate quads. 45-degree back extension (above) Why: to handle the G-forces and eccentric forces of skiing, you need a strong posterior chain, a major part of core strength. Muscles activated: the "posterior chain": hamstring, glutes, erector spinae (lower back). How to: bend from the waist holding weight and raise until torso is parallel to legs. Heel elevated step up (above) Why: helps isolate the vastus medialis, especially the vastus medialis oblique fibres. Muscles activated: vastus medial. How to: with one foot slightly turned out on a step (so that it is at a 45-degree angle), bend the knee to touch the opposite foot to the ground. Stay upright and avoid bending from the hips. Try between 12 to 20 reps. A different type of snow business Downhill skiing increases your cardio-vascular fitness, tones your muscles and can burn up to 3,000 calories a day (about 400 calories per hour). But of all the winter activities, skiing is among the least cardio intensive. If you want to supercharge your next winter holiday, here are six calorie-crunching alternatives. Cross country/Nordic skiing What is it: touring across flat or undulating terrain on thin skis using poles to propel yourself. Calories burned: about 550 calories per hour for moderate cross-country skiing up to a whopping 775 calories per hour for intensive. Benefits: works the upper and lower body through the simultaneous pulling and pushing motion of the arms and legs. As far as workouts go, it's as tough as they come. Every major muscle group is involved. Requiring balance and coordination, it also activates the smaller "stabilising" muscles. Where to do it: unless you're able to journey to a Nordic country, where cross-country skiing began, try skiing the Olympic cross-country course from the 1998 Nagano Winter Olympics in Hakuba, Japan. evergreen-hakuba.com Powder skiing What is it: skiing on fresh powder snow, otherwise known as off-piste skiing, using wider and longer skis. Powder skiing can be done after heavy snowfall or by heli-skiing. Calories burned: about 600 calories per hour, depending on the number of runs and the depth of the snow. Benefits: if you thought regular skiing sizzled your quads, powder skiing sets them on fire. The muscles of the lower body are heavily relied on, mainly the gluteal muscles, as are your core muscles. Requiring a jump and swivel motion to "surf" above the powder, powder skiing requires more cardiovascular fitness than regular, on-piste skiing. Where to do it: for guaranteed powder skiing, try heli-skiing with the inventors of the sport, CMH Heli-Ski in Canada. canadianmountainholidays.com Snowshoeing What is it: hiking in the snow with specially designed shoes. These have a wide metal frame around a net to stop you from sinking through the snow. Poles can also be used for extra stability. Calories burned: around 500 calories per hour. Benefits: snowshoeing is a low-impact cardio workout, requiring strength, agility, balance and endurance. Because you are battling the sinking effect of the snow, each movement is more strenuous and you burn twice as many calories an hour than simply walking. Where to do it: head into the mighty Himalayas in Gulmarg, Kashmir - if you're feeling brave. K-Line Himalayan Adventure Sports offer back country ski tours which can also incorporate snowshoeing on request. klinehimalaya.com Tobogganing What is it: a toboggan is a simple plastic sled. Sit on it, slide down a slope and have a good giggle along the way. Calories burned: up to 468 per hour. Benefits: it might seem easy, but lugging a sled up a hill, holding on for your life as you rocket downhill and repeating a few times is harder work than it sounds. Besides, all that laughing is bound to burn a few extra calories. Where to do it: South Korea's Ttukseom Hangang Park has a theme park that operates a swimming pool in summer, an amusement park in spring and autumn, and a snow sledding hill from December through February. hangang.seoul.go.kr Snowmobiling What is it: much like a jet-ski that rides over snow, not water. Many ski resorts offer snowmobiling tours to see the countryside at high speed. Calories burned: least calorie intensive of them all, snowmobiling burns upwards of 234 calories per hour. Benefits: unless you've ridden a snowmobile, you may not realise the effort required to tame a 300kg machine. Snowmobiles are heavy and require considerable effort and strength to manoeuvre. The abdominals and back muscles get a workout while you move from side to side around a course, and the arms and legs - especially the inner thighs, or adductors - are utilised by merely hanging on as you hurtle across the snow. Where to do it: some of the best snowmobiling courses in the world can be found in Whistler on the west coast of Canada. whistlersnowmobile.com Ice skating What is it: the timeless Olympic sport of moving over ice using ice skates, although you don't have to be as graceful as the pros to reap the benefits. Calories burned (per hour): 350 calories of moderate ice skating and up to 500 calories during a more intense session. Benefits: easy on the joints, calorie-burning cardio while still being fun. Skating burns double the amount of calories compared to walking. Try a pirouette for some extra burn. Where to do it: Hong Kong is home to several ice rinks. One of the most popular is at Festival Walk, Kowloon Tong. *All calories are based on an average person weighing 68kg Correction: A previous version of this article misstated the name of K-Line.