Lab 13/14 EMG and Biofeedback

Electrode Preparation and Equipment Setup

• Electrode Requirements

  • Necessary equipment includes electrodes, a computer, and a data collection device.

Understanding Electrical Activity in the Heart

• Experimental Setup

  • When teaching anatomy, a common practice involved having subjects remain in semi-darkness for around one minute before shining a flashlight into their eyes.

  • This demonstration emphasizes the eyes' response: pupils dilate in darkness and constrict with light.

• Electrical Activity of the Heart

  • The heart's electrical waves are transmitted through body fluids, which contain salts.

  • Common terminology includes:

  • Electrolytes: salts in body fluids (similar to those found in drinks like Gatorade).

ECG Electrode Types and Connections

• Biopack ECG Electrode Specifications

  • Electrodes consist of three connections:

  • White: negative lead

  • Red: positive lead

  • Black (sometimes brown): ground lead

  • Correct placement:

  • White electrode is placed on the right wrist.

• Project Overview

  • Conducting a test with heavyweight boxers to compare the effectiveness of a custom mouthpiece versus a general mouthpiece made by dentists.

  • Example participant:

  • A heavyweight boxer, ranking tenth globally, weighing 220 pounds and measuring 6'8”.

  • Body fat percentage measured at 2.2%.

EKG Terminology and Data Collection

• Electrode and Lead Definitions

  • "Leads": the wires used to collect data from electrodes.

  • The output from these wires is also referred to as leads.

  • In a 12-lead EKG, 10 wires must be connected.

  • 12 lead does not imply 12 wires but specific measurements achieved from 10 connections.

• Visualization of Heart Activity

  • The number of leads affects the views of the heart captured.

Measuring Sweat Rate with ED

• Introduction to EVA Measurement

  • Set up involves attaching two electrodes to measure the electrical difference, referred to as ED.

  • The primary measurement: sweat rate, which consists of water and electrolytes.

  • Increased sweating changes the measured electricity due to variations in electrolyte composition.

Set Up for EMG Measurements

• Electrode Positioning for EMG

  • A setup requires three electrodes: typically red, green, and white.

  • The red electrode should be placed at a higher position compared to the others.

  • Proper positioning increases muscle activity detection:

  • Incorrect positioning yields low activity readings.

• Setting Up the Experiment

  • Using different subjects for the EMG setup compared to previous experiments for accuracy.

  • Electrode placements mirrored on both arms to ensure a balanced comparison of muscle activity.

  • Warning on reversing electrodes: correct placement is crucial for accurate readings.

• Data Collection Procedure

  • The procedure emulates a timer system, similar to a drive-through timer at a fast food restaurant.

  • Clear instructions are provided to subjects before reading begins:

  • Participants instructed to contract and relax arm muscles while data is collected.

• Evaluating Data Validity

  • Expected data pattern includes progressive growth in readings from $25$, $50$, $75$, to $100$.

  • If data does not meet expectations, a redo should be implemented to ensure reliable measurements.

Additional Considerations and Equipment

• Nondominant Arm Characteristics

  • Observations regarding the nondominant arm typically demonstrate less coordination, affecting EMG data quality.

• Equipment Configuration

  • Biopack or similar machines should be equipped with a power cord and necessary connections to operate effectively.

  • Need for accurate login credentials: username and password to access equipment and software.

  • Setup should be immediate to maximize efficiency of simultaneous measurements on two subjects.

• Final Steps

  • Once equipment is powered and logged in properly, the data collection interface will activate for use.