The aim of this study was to predict the risk of hamstring (posterior quadriceps) muscle injury associated with weakness in eccentric muscle strength. The Prone ISO and Nordic tests were performed using the NordBord system from VALD to compare isometric and eccentric contractions of the same muscle group, namely the hamstring muscles, in professional soccer players competing in the Iraqi Stars League. The mean value of the Prone ISO test, which represents maximal isometric contraction, was 353.8 N, whereas the mean value of the Nordic test, which represents maximal eccentric contraction, was 288.6 N. This difference indicates a potential risk factor related to insufficient eccentric contraction capacity of the hamstring muscles. The findings demonstrated weakness in the eccentric contraction phase of the hamstring muscles. This weakness may be explained by several factors, including insufficient eccentric training of these muscles using specific exercises such as the Nordic exercise, Romanian deadlift (RDL), or other exercises designed to develop eccentric contraction capacity. If the players already perform these exercises, it is possible that they do not perform them with maximal effort against body-weight resistance, or that they require additional external loads to increase eccentric contraction capacity. The researcher recommends the use of modern testing methods, including those used in the present study, to identify optimal muscular performance and contraction capacity. Emphasis should also be placed on exercises that develop eccentric contraction of the hamstring muscles to protect them from potential injury during high-speed running and to improve their functional performance