Cooling Induces Motor Facilitation With Sympathetic Activation

Study Overview
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Brief Summary
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Cryotherapy has beneficial effects such as motor facilitation, increase isometric force generation, and reduce spasticity. It is known that the muscle spindle has sympathetic innervation. Muscle spindle sensitivity increase with sympathetic activity. This research has three hypotheses: First, short-term cold application to the skin increases sympathetic activity. Second, there is an increase in muscle spindle sensitivity with increased sympathetic activity. Third, the effect of short-term cold on muscle spindle sensitivity continues until the skin temperature returns to normal. The purpose of this research is to test these hypotheses.

Detailed Description
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Cryotherapy is a frequently used treatment method in sports medicine and rehabilitation due to its beneficial neuromuscular effects. Its main beneficial effects are motor facilitation, increase isometric force generation, and reduce spasticity. The motor effects of cryotherapy may differ depending on the duration of application, the coolant used agent (ice, ice water, coolant spray, etc.), and the thickness of the subcutaneous adipose tissue. The short-term cold application increases the force of contraction with motor facilitation. As the cold application period gets longer, the effects of the cold that inhibit motor functions such as gamma motor neuron inhibition, muscle spindle inhibition, and muscle conduction block come to the fore. It is known that the muscle spindle has sympathetic innervation. It has been reported in recent studies that mental arithmetic, cold application to the skin, isometric contraction of remote muscles, and ischemia increase muscle spindle sensitivity through increased sympathetic activity. However, there are very limited studies showing that cold application increases muscle spindle sensitivity through increased sympathetic activity. On the other hand, in terms of determining treatment and rehabilitation strategies, it is important to know how long the effect of the cold application on muscle spindle sensitivity continues. However, it is not clear how long the effect of the cold application on muscle spindle sensitivity lasts after the cold application ends. There is a widespread belief that the motor facilitation effect of cryotherapy can occur with the stimulation of cutaneous cold receptors. Considering this view, it can be thought that the effect of the short-term cold application on muscle spindle sensitivity continues until the skin temperature returns to normal. This research has three hypotheses: First, short-term cold application to the skin increases sympathetic activity. Second, there is an increase in muscle spindle sensitivity with increased sympathetic activity. Third, the effect of short-term cold on muscle spindle sensitivity continues until the skin temperature returns to normal. The purpose of this research is to test these hypotheses.

Official Title
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Brief Skin Cooling Induces Muscle Spindle Sensitivity With Heightened Sympathetic Outflow

Conditions
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Cryotherapy Effect

Intervention / Treatment
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* Other: Brief skin cooling


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Being healthy Being a young adult (20-45 years old) Volunteer Exclusion Criteria: Scar, dermatitis, etc. in the skin tissue where the superficial electromyography electrode will be placed Upper extremity bone and joint disease, history of neuromuscular disease Heart disease, Hypertension Cold intolerance

Ages Eligible for Study
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Minimum Age: 20 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Male

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: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Hand cooling<br>Records will be taken for Baseline electromyography, Heart rate, H-reflex, and T-reflex measurements before, during, and at 0, 3, 6, 9, 12, and 15. minutes before applying 2-4 degrees Celsius cold to the back of the hand in this group. | Other: Brief skin cooling<br>* Brief skin cooling will be applied to the hand using the cold-bath immersion<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change from baseline in Heart rate | Heart rate will be monitored with DII derivation electrocardiographic recording.Heart rate will be reported as beats per minute. | Baseline (pre-cold pressor test) and 0, 3, 6, 9, 12, 15 minutes post-cold pressor test | 
| Change from baseline in Soleus H-reflex | By stimulating the tibial nerve with an electrical current, the Soleus H-reflex will be obtained. Its peak to peak amplitude will be measured in microvolts. | Baseline (pre-cold pressor test) and 0, 3, 6, 9, 12, 15 minutes post-cold pressor test | 
| Change from baseline in T-reflex | Soleus T-reflex will be obtained by hitting the Achilles tendon with the electronic reflex hammer. Its peak to peak amplitude will be measured in microvolts. | Baseline (pre-cold pressor test) and 0, 3, 6, 9, 12, 15 minutes post-cold pressor test | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Skin temperature | The skin temperature of the back of the hand exposed to the cold application will be measured with an infrared thermometer and the results will be reported in degrees Celsius. | Baseline (pre-cold pressor test) and 0, 3, 6, 9, 12, 15 minutes post-cold pressor test | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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muscle spindle, sympathetic outflow, motor facilitation