As a traditional water sport, water-skiing is a high-risk sport, like alpine skiing or soccer. In the introductory part of this thesis, the anatomy of the knee will be defined. Then the functional properties of the knee and its ligaments will be explained, including knee movements, the stability of the knee and the biomechanics of the knees ligaments. This knowledge will help the reader understand the content of the scientific part of this paper. Considering the ligamentous injuries, we focus on ACL and PCL injuries. Water-skiing is a 3-event sport and every discipline involves different movement patterns that may lead to variable injury patterns due to the diverse cutting, pivoting and deceleration movements. As our study will reveal, the most dangerous discipline is Jumping. Here, the high speed of the boat and the skier himself aggravate the impact onto the water during a crash. Knee injuries caused by water-skiing show a high association with a prolonged season on the water, possibly due to overuse or fatigue of the ligaments and muscles supporting the joint. After treating a ligamentous injury, either conservatively or surgically, the knees ROM can be limited and pain may still be present. Those two restrictions will influence the skiers’ performance. It may even force him or her to quit the sport, which, fortunately, rarely happens. For the injured skier it is essential to undergo proper treatment and rehabilitation, so that the knees strength returns to its pre-injury level. If the joint does not manage to reach full strength, it can be due to structural changes of the implanted graft, wrong placement of the graft, or falsely executed rehabilitation program. The former two will cause weakness of the ligament itself, and the latter will result in weaker muscles. The aim of this study was to identify and obtain as much information from professional water skiers as needed to point out any possible preventative measures, as well as any association between a specific factor or training pattern and injury occurrence.