Integration of a Knee Flexor Bias or Hip Hinge Bias Resistance Training Program With Combined High-Speed Running in Academy Soccer Players.

Hamstring strains remain one of the most common injuries in soccer, and strength training aimed at the hamstring muscles is often used to try to reduce that risk while also supporting sprint and jump performance. This trial looked at whether the specific type of exercise used matters when strength training is combined with high-speed running drills, comparing a hip-hinge style exercise, the Romanian deadlift, against a knee-flexor focused exercise, the Nordic hamstring exercise, alongside a control group that did neither. Over six weeks, both exercise groups gained knee flexor strength compared with control, so either approach appeared to build strength in that muscle group. However, improvements in sprinting and jumping were larger in the group doing the Nordic hamstring exercise than in the Romanian deadlift or control groups.

This is a single, fairly small trial in young academy players, so how well the results generalize to older or more experienced athletes, or hold up over longer training periods, is not established.

If you play or coach soccer, you have probably heard that hamstring injuries are common and that certain strength exercises are meant to help prevent them. This study tested two different strength exercises, done alongside sprint training, in a group of young academy soccer players over six weeks: one that hinges at the hip, the Romanian deadlift, and one that specifically works the back of the thigh through knee bending, the Nordic hamstring exercise.

A third group did neither exercise. Both exercises made the hamstring muscles stronger compared with doing no extra exercise. But when it came to sprinting speed and jumping ability, the group doing the Nordic hamstring exercise showed bigger improvements than the other two groups. This was a modest-sized study involving 37 young male players over a short six-week period, so it cannot tell us whether these benefits last longer, apply to other age groups, or actually translate into fewer hamstring injuries on the field.

It only measured strength, sprint, and jump performance, not injury outcomes.

This is a summary of research, not medical advice. Talk to your own healthcare provider about anything affecting your care.

This randomised controlled trial assigned 37 male academy soccer players (mean age 17.1 years) to a Romanian deadlift group, a Nordic hamstring exercise group, or a control group, each undertaking six weeks of training combined with curvilinear high-speed running. Both intervention groups showed statistically significant improvements in knee flexor strength relative to control (p ≤ 0.05, Hedges' g = 0.85–1.62), indicating that either exercise modality, when paired with sprint work, can enhance hamstring strength over this short timeframe. For sprint (g = 1.14–1.44) and jump performance (g = 1.08–1.57), effect sizes favoured the Nordic hamstring exercise group over both the Romanian deadlift and control groups, suggesting a knee-flexor-biased stimulus may transfer more effectively to these performance measures within this protocol.

The abstract does not report whether the Nordic and Romanian deadlift groups were statistically compared directly against each other for sprint and jump outcomes beyond the effect size ranges given, so caution is warranted in claiming definitive superiority. Limitations include the small sample size, short six-week duration, single population (academy-level youth players), and the absence of any hamstring injury incidence data, meaning strength and performance gains cannot be assumed to translate into reduced injury risk.