Action Mechanisms of Shock Waves on Pain

Study Overview
=================
Brief Summary
-----------------
The aim of this study is to evaluate whether the intensity of pain perceived during the application of extracorporeal shockwave therapy (ESWT) is determinant for producing changes in pressure pain threshold (PPT) in asymptomatic subjects. The investigators will perform a single controlled random trial to three groups. Two of them will receive ESWT whereas the third group will get a cold pressure test (CPT).

Official Title
-----------------
Action Mechanisms Responsibles for the Effects of Shock Waves on the Pressure Pain Thresholds

Conditions
-----------------
Asymptomatic Condition

Intervention / Treatment
-----------------
* Other: Sham Comparator
* Other: Experimental Intervention
* Other: Control Group


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Absence of pain or illness No changes in cognitive ability Good command of Spanish, both spoken and written Exclusion Criteria: People with systemic diseases, tumors, infections, pacemakers, clotting disorders, skeletally immature, fibromyalgia, whiplash history, dizziness or in physiotherapeutic or pharmacological treatment Pregnant women

Ages Eligible for Study
-----------------
Minimum Age: 18 Years
Maximum Age: 40 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
Accepts Healthy Volunteers

Study Plan
=================
How is the study designed?
-----------------

Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Shockwave Light Pain Group<br>Sham Comparator. It will received a light intensity shockwave in the lateral epicondyle regulated until reach a 3/10 in the Visual Analog Scale (VAS) scale. | Other: Sham Comparator<br>* The investigators will apply a light intensity shockwave in the lateral epicondyle with the portable SHOCKMASTER 300 at a 8Hz frequency and 2000 impulses. The intensity will be regulated to reach a 3/10 in the VAS scale, depending on the tolerance of the subject. Each patient will receive between 5 and 10 impulses starting with the lower intensity of the device (middle energy: 1 bar) and will go up towards the target (3/10 in VAS).<br>|
| Experimental: Shockwave Moderate Pain Group<br>Experimental Intervention. It will received a moderate intensity shockwave in the lateral epicondyle regulated until reach a 6/10 in the Visual Analog Scale (VAS) scale. | Other: Experimental Intervention<br>* The investigators will apply a moderate intensity shockwave in the lateral epicondyle with the portable SHOCKMASTER 300 at a 8Hz frequency and 2000 impulses. The intensity will be regulated to reach a 6/10 in the VAS scale, depending on the tolerance of the subject. Each patient will receive between 5 and 10 impulses starting with the lower intensity of the device (middle energy: 1 bar) and will go up towards the target (6/10 in VAS).<br>|
| Other: Cold Pressure Group<br>Control Group. The cold pressure test will be apply to this group. The investigators will use a container with an outer part filled with ice and an inner part filled with water, both separated by a screen that prevents direct contact between the ice and the hand. The water will be regularly stirred to maintain the temperature near to 0.7ºC. | Other: Control Group<br>* Patients will place their hand, wide open and up to the wrist, into the inner part of the container and will keep it under water for a maximum time of 2 minutes. If pain is unbearable before the time ends, the participant will be able to withdraw the hand.<br>|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pressure pain threshold | The investigators will use a digital algometer (Force Ten FDX Wagner) to measure when pressure becomes pain. | through study completion, an average of 1 month |