The Effect of 6 Week Hamstring Exercise Programs on Hamstring Muscle Strength

Study Overview
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Brief Summary
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This study aims to compare the effect of two hamstring strengthening programs on hamstring muscle strength in university students. 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.

Detailed Description
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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 will be recorded before and after the exercise intervention. A 10 point visual analogue scale will be used to record the level of muscle soreness experienced after each training session.

Official Title
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The Effect of a 6 Week Nordic Hamstring Exercise and an Assisted Nordic Hamstring Program on Hamstring Muscle Strength

Conditions
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Hamstring Injury

Intervention / Treatment
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* Other: Nordic hamstring exercise program
* Other: Assisted nordic hamstring exercise program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: free from hamstring injury in the 6 months prior to the study currently competing in team sports at least three occasions per week Exclusion Criteria: history of a hip or knee injury in the 3 months prior to the study a history of anterior cruciate ligament rupture a history of involvement in a hamstring strengthening, injury prevention programme in the 3 months prior to the study.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Nordic hamstring exercise program<br>Participants are required to kneel on a gym mat keeping their hips in a slightly flexed position and to slowly lower themselves in a controlled manner as far as they could towards the ground. When they can no longer lower themselves as such, they are instructed to utilise their arms to buffer the fall and touch their chest off the ground, while maintaining tension in their hamstrings. Once their chest touches the ground they are instructed to immediately return to the starting position by pushing up with their hands | Other: Nordic hamstring exercise program<br>* 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.<br>|
| Experimental: Assisted nordic hamstring exercise program<br>Participants are required to kneel on a gym mat keeping their hips in a slightly flexed position and to slowly lower themselves in a controlled manner as far as they could towards the ground. During this exercise, participants are attached to a weighted pulley cable system via a chest attachment. A sufficient amount of assistance is given to allow the participant to lower to 30 degrees of knee flexion. When they can no longer lower themselves as such, they are instructed to utilise their arms to buffer the fall and touch their chest off the ground, while maintaining tension in their hamstrings. Once their chest touches the ground they are instructed to immediately return to the starting position by pushing up with their hands | Other: Assisted nordic hamstring exercise program<br>* 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.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| 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. | Change from baseline after 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 | Change from baseline after 6 weeks | 
| Hamstring strength endurance | This will be measured by assessing the number of repetitions of the single leg bridge exercise to failure | Change from baseline after 6 weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Muscle soreness ratings 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. | immediately following each session | 
| between limb asymmetries in hamstring strength, moment and endurance. | percentage between limb asymmetries will be calculated | Change from baseline after 6 weeks | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Eccentric hamstring strength, Nordic hamstring exercise