<![CDATA[ The aim of this study was to investigate the effect of preventive exercises using a flywheel on improving eccentric muscle strength and flexibility of the hamstrings in football players. The researcher employed an experimental approach with a two-group design—an experimental group and a control group—using pre- and post-tests, as this was appropriate to the nature of the research problem and its objectives. The study sample consisted of 20 advanced footballers, who were randomly divided into two equal groups: 10 players in the experimental group and 10 in the control group. The experimental group undertook a preventive programme using a flywheel device for 12 weeks, comprising three training sessions per week, totalling 36 training sessions, with each session lasting 20 minutes. The loads were progressively increased from the structural adaptation and safety phase, through the eccentric strength development phase, to the phase of eccentric overload and speed. The researcher used the Nordic Drop test to assess eccentric strength of the hamstrings and the active straight leg raise (ASLR) test to assess flexibility of the hamstrings. The results presented in the study showed an improvement in eccentric strength in the experimental group from (42.30 ± 2.15) to (61.80 ± 1.90), representing an improvement of (46.10 per cent), whilst the improvement in the control group was (5.48 per cent). Flexibility of the hamstrings in the experimental group also improved from (64.50 ± 3.10) to (78.90 ± 2.20), representing an improvement of (22.32 per cent), compared with (3.37 per cent) for the control group. The results indicate that the proposed preventive programme using the flywheel device was more effective in developing eccentric strength and flexibility of the hamstrings compared with the conventional programme, within the limits of the study design and the data used.]]>
