This study aims to compare the effect of two hamstring strengthening programs on hamstring muscle strength in female university athletes. 60 participants will be recruited for this study. They will be randomly assigned to one of two 6-week hamstring strengthening programs, namely the single leg bridge exercise and the Nordic hamstring exercise protocol, and one control group. Eccentric and isometric hamstring strength, gluteal strength and will sprint speed will be measured before and after the intervention.
Participants will be recruited from the local university sports clubs. Club chairpersons will be asked to send an email to club players. Players interested in participating in the study will be asked to attend a meeting where the study will be explained to them. Those who were interested will then be assessed for inclusion and exclusion criteria. Group allocation: A four block randomization method will be used to allocate participants to the Nordic hamstring exercise protocol or the single leg bridge protocol. Interventions: The Nordic hamstring exercise program or the single leg bridge program. Testing procedure: The eccentric strength of the participants' hamstrings and hip extensors will be recorded before and after the exercise intervention. 30 metre sprint performance will be recorded before and after the intervention. A 10 point visual analogue scale will be used to record the level of muscle soreness experienced after each training session.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
47
Week 1 - 1 session per week consisting of 2 sets of 5 reps of the exercise Week 2 - 2 sessions per week consisting of 2 sets of 6 reps of the exercise Week 3 -3 sessions per week consisting of 3 sets of 6 reps of the exercise Week 4 - 3 sessions per week consisting of 3 sets of 8 reps of the exercise Weeks 5 and 6 - 3 sessions per week consisting of 3 sets of the exercise. Set 1 with 12 reps, set 2 with 10 reps and set 3 with 8 reps
Week 1 - 1 session per week consisting of 2 sets of 5 reps of the exercise Week 2 - 2 sessions per week consisting of 2 sets of 6 reps of the exercise Week 3 -3 sessions per week consisting of 3 sets of 6 reps of the exercise Week 4 - 3 sessions per week consisting of 3 sets of 8 reps of the exercise Weeks 5 and 6 - 3 sessions per week consisting of 3 sets of the exercise. Set 1 with 12 reps, set 2 with 10 reps and set 3 with 8 reps
Dublin City University
Dublin, Ireland
eccentric hamstring strength
This will be measured using devices that measure the eccentric strength of the hamstrings during the Nordic hamstring exercise. The devices are called the Hamstring Solo device and the Nordbord device. Participants will kneel on the padded surface of the device with their lower limbs held in position just above the ankles. The ankle supports have load sensitive cells. The participants will be asked to complete the nordic hamstring exercise. This involves them folding their arms across their chest and slowly lowering themselves towards the ground by allowing their knees to slowly straighten. The load cells will record the force (newtons) during the exercise for each leg.
Time frame: Change from baseline 6 weeks
eccentric hamstring moment
This will be measured using devices that measure the eccentric strength of the hamstrings during the Nordic hamstring exercise. The devices are called the Hamstring Solo device and the Nordbord device. Participants will kneel on the padded surface of the device with their lower limbs held in position just above the ankles. The ankle supports have load sensitive cells. The participants will be asked to complete the nordic hamstring exercise. This involves them folding their arms across their chest and slowly lowering themselves towards the ground by allowing their knees to slowly straighten. The load cells will record the force (newtons) during the exercise for each leg. The distance from the load cells to the knee joint will be measured (meters) to calculate the moment in Newton meters for the exercise
Time frame: Change from baseline 6 weeks
isometric hamstring strength and moment
Isometric knee flexor strength will be assessed by placing the participant in prone with the hip in 0° extension and 30° in knee flexion. The investigator will hold the dynamometer 5cm above the lateral malleolus in the posterior midline. The participant will be asked to bend their knee by attempting to pull their heel towards their bottom
Time frame: Change from baseline 6 weeks
isometric hip extensor strength and moment
Hip extensor strength will be assessed by placing the participant in a prone position with their tested leg in 0° hip extension and 90° knee flexion. The handheld dynomometer will be held by the investigator against the heel of the participant. The participant will be instructed to raise their leg upwards against the resistance of the investigator. This will be repeated with the hip placed in 30 degrees flexion
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Week 1 - 1 session per week consisting of 2 sets of 5 reps of the exercise Week 2 - 2 sessions per week consisting of 2 sets of 6 reps of the exercise Week 3 -3 sessions per week consisting of 3 sets of 6 reps of the exercise Week 4 - 3 sessions per week consisting of 3 sets of 8 reps of the exercise Weeks 5 and 6 - 3 sessions per week consisting of 3 sets of the exercise. Set 1 with 12 reps, set 2 with 10 reps and set 3 with 8 reps
Time frame: Change from baseline 6 weeks
Sprint performance
Participants will perform three maximal 30 metre sprint tests with 4 minutes of recovery in between. Time elapsed will be recorded by timing gates placed at 0m, 5m, 15m, and 30m. Participants will start from a standing split position. The first timing gate will be triggered at initial toe off of the back leg. Times will be recorded and mechanical sprint variables (maximal horizontal force production, maximal horizontal power output and maximal theoretical velocity) will be calculated using an Excel spreadsheet (Samozio et al., 2016). The participants best time of the three attempts will be recorded.
Time frame: Change from baseline 6 weeks
Muscle soreness following exercise
Participants will use a ten point numerical rating scale to record the level of muscle soreness after training sessions. The scale will range from 0 to 10 where 0 is no pain and 10 is the most severe pain imaginable.
Time frame: Following each session