The goal of this paper is a biomechanical analysis of correct and incorrect techniques of the roundhouse kick in taekwondo in order to determine the risks of injuries for the purpose of their prevention. The roundhouse kick was chosen because it is the most commonly executed kick in this martial art. The analysis was performed using the Perception Neuron 2.0 motion capture system and the Biomechanics of Bodies software for data processing. Firstly, an overview of the correct technique and knee injuries that can occur if it is not consistently performed is provided. The movement defined as correct is based on the proper technique of the roundhouse kick, while in the case of incorrect movement, the element of turning the standing leg is omitted. The movement was performed twice incorrectly and then twice correctly, first with the right leg and then with the left leg. The obtained results indicate that correct execution involves rotation of the standing leg, rotation of the pelvis and rotation of the hips, correct trajectory of the kicking leg, activation of the internal abdominal oblique muscle, and a change in the position of the body's center of gravity. Incorrect execution, on the other hand, leads to limited mobility of the kicking leg and pelvis and reduced activation of the internal abdominal oblique muscle. Additionally, the conditions of balance and stability of the body are altered. Errors in execution create mechanisms of injury, whether it's repetitive microtrauma over a longer period of time or short-term overload. The analysis highlights the importance of proper technique in preventing injuries, especially of the knee ligaments. The results are in line with the learning guidelines and can confirm the interdependence between all the elements of the movement. This analysis can provide useful information to coaches and athletes as a part of the training and learning process.