Hamstring strains are among the most common injuries in field sports, accounting for 10% of all team sports injuries and often leading to long-term absence from activities. Risk factors include older age, previous injuries, reduced flexibility, and strength deficits. The hamstrings play a critical role in dynamic stability and joint preservation, particularly for the hip and knee. While stretching is crucial for injury prevention, there is debate over optimal techniques. The neurodynamic sliding technique (NST) and eccentric training (ET) are two methods that can improve flexibility and reduce injury risk. This study uniquely combines ET with NST to address hamstring tightness in athletes, aiming to evaluate their effects individually and in combination on knee muscle strength, range of motion, proprioception, and lower limb function compared to a control group. The hypotheses examine whether these interventions differ in their impact on eccentric and concentric knee strength, the knee flexor/extensor strength ratio, range of motion, proprioception, and dynamic balance (measured via the Y Balance Test). The null hypothesis (H0) proposes no differences, while the alternative hypothesis (H1) suggests significant differences among the intervention methods.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
NONE
Enrollment
54
Following Castellote-Caballero et al., the neurodynamic sliding technique (NST) was applied to the dominant leg's sciatic nerve in the NST and ETNST groups. The technique involves alternating stress proximally and distally to promote nerve sliding. Participants performed two sets of movements-cervical flexion with knee and ankle flexion, and cervical extension with knee and ankle extension-repeated actively for 60 seconds, five times per session. Over six weeks, both groups underwent three supervised sessions per week led by an experienced researcher.
The Nordic exercise served as the foundation for the intervention, focusing on eccentric loading as participants resisted falling forward. To minimize DOMS and ensure adherence, a two-week preparatory phase of mixed concentric/eccentric leg curls using a stability ball was implemented. Following this, the gradual progression outlined by Mjolsnes et al. led to a four-week Nordic hamstring curl regimen. Weekly supervision ensured proper technique and compliance throughout the program.
Yeditepe university
Istanbul, Ataşehir, Turkey (Türkiye)
Passive Straight Leg Raise (SLR) test
To measure passive hamstring flexibility, participants will lie supine on a bed with their pelvis and opposite thigh secured using straps to prevent compensatory movements. A goniometer will be positioned with its axis at the greater trochanter of the femur, the fixed arm aligned with the midaxillary line, and the moving arm along the lateral malleolus. With the knee extended and the ankle in a neutral position to avoid calf muscle stiffness, the thigh is gently flexed until hamstring tightness is felt. The straight leg's elevation angle will be measured three times, and the average will determine hamstring flexibility. Individuals with an angle less than 75° are classified as having short hamstring muscles.
Time frame: 1-2 minutes
Knee muscle strength
Quadriceps and hamstring strength will be measured using the Biodex Pro 3 isokinetic device. Participants will sit comfortably with their trunk, pelvis, and thigh secured by straps, and the dynamometer axis aligned with the knee joint's center of rotation. After adjustments for proper positioning, the test leg will be attached to the device. Following familiarization and warm-up contractions, participants will perform maximum effort tests. Strength will be evaluated at angular speeds of 60°/s and 120°/s in both concentric and eccentric modes, with knee joint movement controlled between 0° and 90°.
Time frame: 10 minutes
Knee joint proprioception
Knee joint proprioception was assessed using the Biodex dynamometer in continuous passive motion mode at a constant speed of 5°/s. Participants sat with knees and hips bent at 90°, aligned with the dynamometer's axis, while wearing a blindfold and pneumatic boot to block visual and tactile cues. The test involved 90° of knee movement, from full extension (0°) to full flexion (90°). After practice trials, participants aimed to identify a target position (60°) during knee flexion and hit an abort button when they believed they reached it. The deviation from the target position was recorded based on three repetitions.
Time frame: 10 minutes
Y balance test
YBT test performance was assessed with a Y Balance Test Kit. Before assessment, participants were acquainted with the Y-Balance Test (YBT) by practicing on their injured limb. The YBT was performed on a platform. Throughout the task, the standing leg remained on the platform, while the other leg executed error-free maximum reach in three directions: anterior, posteromedial, and posterolateral. Maximum distances in each direction, relative to the stance leg, were measured. During the test, participants kept their hands on their waists, and each direction was repeated three times with a 10-second rest between trials.
Time frame: 15 minutes
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.