The Winter Paralympics officially start on Friday, with the opening ceremony in Verona, Italy.With more than 600 Paralympic athletes and 79 sets of medals to be awarded, Milan Cortina will feature a record number of athletes and medals.They will compete across six sports: Para alpine skiing, Para biathlon, Para cross-country skiing, Para ice hockey, Para snowboard and wheelchair curling.In the skiing sports — Para alpine skiing, Para biathlon, Para cross-country skiing — athletes compete in one of three categories: standing, sitting (on a sit-ski or monoski) or vision impaired (who race following a guide connected via radio).Guides also receive medals.Within each of these three categories, skiers compete in different divisions depending on their functional ability. A results calculation system determines the factored time of each athlete, which allows athletes from different divisions to race against each other.Here's a look at the sports:Para alpine skiingIntroduced at the first Winter Paralympics in 1976, it includes five events: slalom, giant slalom, super-G, downhill and super combined.There are 30 medal events – 15 for men and 15 for women.In the sitting category, athletes use a specialized monoski, a seat mounted on a single ski with a shock absorber that helps with riding on uneven terrain and making turns.In Para biathlon and Para cross-country, the sit-ski is a sitting device mounted on a pair of cross-country skis.Para alpine skiing will take place on the Olympia delle Tofane course in Cortina d'Ampezzo, the same iconic course that held the women's alpine skiing at the recently concluded Winter Olympics.Para biathlonCombines the strength and endurance of cross-country skiing with the precision and composure of target shooting.There are three events in each class – 7.5-kilometer sprint, 12.5-kilometer individual and sprint pursuit – and men and women compete in separate races, for a total of 18 medal events.The ski course is tackled several times, and between each lap, athletes shoot at five metal targets placed 10 meters away. For each missed shot, they get a time penalty or have to ski a penalty loop, depending on the event.Athletes with disabilities in the upper limbs can be assisted by their coaches in positioning the rifle and pulling the trigger at their direction. In the vision impairment category, athletes are aided by acoustic targets that indicate how close they are to the target before shooting.The sport was introduced for athletes with physical disabilities at the 1988 Innsbruck Paralympic Games and for athletes with visual disabilities in 1992 at Albertville.At Milan Cortina, Para biathlon will take place at the Tesero Cross-Country Skiing Stadium.Para cross-country skiingThis will also take place in Tesero and has a total of 20 medal events.There are three events for men and women (across the three categories): sprint, 10-kilometer interval start classic, 20-kilometer interval start free. There is also the mixed 4x2.5-kilometer relay, and open 4x2.5-kilometer relay.For each competition, there are separate courses for athletes in the sitting category and for athletes in the standing and vision impaired categories. The courses for the athletes in the sitting category have lower gradients as the athletes rely on the upper body for pushing/pulling themselves forward while on a sit-ski.A relay team can be made up of two, three or four athletes (plus guides as appropriate) with athletes able to ski more than one leg.Para ice hockeyPara ice hockey was invented at a rehabilitation center in Stockholm, Sweden, during the early 1960s by a group of Swedes who, despite their physical impairment, wanted to continue playing hockey.It debuted in the Winter Paralympics at Lillehammer in 1994 and involves athletes with a physical disability in their lower limbs. Matches consist of three 15-minute periods.Rather than skates, players use double-bladed sledges that allow the puck to slide underneath and have two sticks, which have a spike-end for propulsion and a blade-end for handling the puck.Para ice hockey is a mixed gender sport, although only two teams at Milan Cortina have a female in their squads — Japan and Slovakia.Moreover, only three female ice hockey players have ever participated at the Paralympic Games: Norwegians Brit Mjaasund Oeyen in 1994 and Lena Schroeder at PyeongChang in 2018, and Yu Jing of China at Beijing in 2022.The United States will be looking to complete a three-peat, having won both the men's and women's tournaments at the recent Winter Olympics. The U.S. has also won the Para ice hockey at five of the past six editions of the Winter Paralympics, with only Canada interrupting that streak in 2006.The competition will take place at the new Santagiulia arena in Milan. There are eight teams, split into two groups. The teams play each other team in their group once in a round-robin format, with the top two from each group advancing to the semifinals.Para snowboardDebuted in Sochi in 2014 as part of the alpine skiing program, although there have been a varied number of events at subsequent Olympics.At the Milan Cortina Games, there are two events across three categories for men, depending on the disability and one category for women.There are two categories for men with lower-limb impairments and one for those with upper-limb impairments, while there is one category for women with lower-limb impairments.Para snowboarders with a disability affecting one or both legs can use prosthetics or modified equipment to compete.The two events are banked slalom and snowboard cross and will take place in Cortina. In banked slalom, athletes get two individual runs down the course with their best time counting toward the final ranking.The heats and the finals of the snowboard cross will see four athletes racing at the same time. The top two advance from the heats and then the first across the finish line in the final wins.Wheelchair curlingThe mixed-team event for athletes with physical disabilities in their legs is celebrating its 20th anniversary after being introduced, the last time the Paralympics were held in Italy, in 2006.Players can choose whether to throw the stone alone or with a teammate who holds the wheelchair steady. Athletes can use an extender to add speed and direction.There are eight ends per game, two fewer than in games at the Olympics, and there is no sweeping.Competition will take place at the Cortina Curling Olympic Stadium, and the program will feature a mixed doubles competition for the first time as well as the regular mixed team event.