Changes in Muscle Activation When Carrying Backpacks

Study Overview
=================
Brief Summary
-----------------
To investigate change of shoulder muscles by measuring muscle activity according to the position of the backpack.

Detailed Description
-----------------
Most of modern people, including students and office workers, wear backpacks for a considerable amount of time. There have been prior studies on the change in muscle activity around the spine and shoulders muscles according to the weight of the backpack, but studies on the change in muscle activity according to the direction of the bag are insufficient. So this study is to evaluate the effect on the musculoskeletal system by comparing the activity of the muscles around the shoulder according to the anterior or posterior wearing of the backpack. Muscles around the shoulder are composed of: Serratus anterior, trapezius(upper and lower) which control scapular movement and deltoid muscles which activate shoulder abduction directly. We would like to focus change of these muscles's activities when carrying a backpack according to the anterior or posterior direction and bilateral or unilateral. To measure muscle activity, eight-channel electromyography (EMG) Using Nicolet EDX (Natus Medical Inc., San Carolos, CA, USA), surface EMG (sEMG) signal were used.

Official Title
-----------------
Changes in Muscle Activation of Serratus Anterior, Deltoid (Anterior) and Trapezius (Upper and Lower) According to the Methods of Carrying Backpacks

Conditions
-----------------
Shoulder Muscle Activation, Surface Emg

Intervention / Treatment
-----------------
* Diagnostic Test: surface EMG


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Healthy adults from 20s to 50s Exclusion Criteria: Restriction of joint motion range of shoulder and elbow Hisory of upper limb surgery in the past 6 months If there is an external wire such as a temporary external pacemaker or central line guide wire

Ages Eligible for Study
-----------------
Minimum Age: 20 Years
Maximum Age: 59 Years

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

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

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

Design Details

Primary Purpose: Diagnostic
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Experimental group<br>Group measuring shoulder muscle activities by surface EMG with carrying backpacks forward | Diagnostic Test: surface EMG<br>* Carrying backpacks forward or backward<br>|

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

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Root mean square of each muscle activation | Quantification of muscle activity | through study completion, an average of 1 year | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
backpack, shoulder muscle activation, surface emg, deltoid, serratus anterior, trapezius