Rate of Leg Curl to Leg Press During Isokinetic Testing

Study Overview
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Brief Summary
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The functional condition of the leg muscles is not only relevant to performance in sports, but is also of great importance in health, prevention and rehabilitation, where not only the general strength level is decisive but also the relationship between individual muscle groups. Among other things the H-Q-ratio (strength ratio of hamstring muscles to quadriceps muscles) is often used to diagnose possible imbalances. Isokinetic force measurements have established themselves as the gold standard in competitive football. In this context, however, force tests in the open kinetic chain (OKC) have almost exclusively been used so far. Especially force measurements in the closed kinetic chain (CKC) could have a higher relevance regarding functionality. The H-Q-ratio should better be called the flex-ext-ratio in the CKC due to the involvement of the hip muscles. There is little data in the literature on leg force or flex-ext-ratio in CKC. In particular, there is hardly any comparative data for isokinetic measurement systems in the CKC. Using a cross over design and randomly allocating 28 competitive football players into two groups (n=14 each) that either started tests with the leg press or legcurl device, the investigators assumed (1) a significantly lower flex-ext-ratio in the CKC compared to the OKC, (2) a correlation between the isokinetic measurement systems in the OKC and the CKC, and (3) a significant superiority of the leg press to predict functional performance of the lower limbs.

Official Title
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Maximum Strength and Ratio of Leg Extension and Leg Flexion in Elite Soccer Players. A Comparison of an Open Versus Closed Isokinetic System

Conditions
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Muscle Strain

Intervention / Treatment
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* Device: Isokinetic leg extension/-flexion on a legpress device
* Device: Isokinetic leg extension/-flexion on a legcurl device


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: male elite soccer players (5th-6th German soccer division) Exclusion Criteria: no acute injuries

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

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Diagnostic
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: leg curl device starters<br>Group A randomly assigned to start with legcurl device | Device: Isokinetic leg extension/-flexion on a legpress device<br>* Maximum strength and rate of leg-flexion /-extension during legpress exercise<br>Device: Isokinetic leg extension/-flexion on a legcurl device<br>* Maximum strength and rate of leg-flexion /-extension during legcurl exercise<br>|
| Experimental: legpress device starters<br>Group A randomly assigned to start with legpress device | Device: Isokinetic leg extension/-flexion on a legpress device<br>* Maximum strength and rate of leg-flexion /-extension during legpress exercise<br>Device: Isokinetic leg extension/-flexion on a legcurl device<br>* Maximum strength and rate of leg-flexion /-extension during legcurl exercise<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Leg extension/leg-flexion rate | Rate of leg extension to leg-flexion | at baseline | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Isokinetic leg extensors strength | Maximum isokinetic strength of the leg extensors as determined by an isokinetic legpress device (Physiomed, Laipersdorf, Germany) | at baseline | 
| Isokinetic leg flexors strength | Maximum isokinetic strength of the leg flexors as determined by an isokinetic legpress device (Physiomed, Laipersdorf, Germany) | at baseline | 
| Y-Balance Test | Dynamic motor-control as determined by the Y-Balance test | at baseline | 
| Maximum jumping height | Maximum jumping height as determined by the counter movement jump | at baseline |