UMass Amherst KIN 460 - Motor Unit Recruitment 9.12.2014 (2 pages)

Lesson 2 EMG II Motor Unit Recruitment and Properties Introduction In 1957 power lifter Paul Anderson set the world record for the heaviest weight ever lifted by a human being at a total of 6 270 lbs According to the Guinness Book of World records no one has yet been able to best his record 1 How was Anderson able to lift such a massive weight In this lab we will learn about the different muscular properties and the mechanisms of motor recruitment which would allow such a feat to occur Setup 1 Set up each workstation accordingly Make sure you have a Computer with Biopac MP3X unit b Hand dynamometer c EMG electrode lead set d Three disposable vinyl electrodes e Conductive gel 2 Attach the electrodes to the forearm The black lead ground should be on radial styloid the red lead positive should be just proximal to the radial styloid and the white lead negative should be on the flexor carpi radialis muscle 3 Start the Biopac program and load the lesson L02 it is Lesson 2 titled EMG II 4 Type in your student ID number Calibration 5 Click calibrate set dynamometer down and click OK 6 After baseline calibration has been completed you will need to get a calibration for the maximum force you can produce When prompted grip the dynamometer as hard as you can for at least two seconds Data Recording We are going to look at your EMG activity during different levels of muscular contraction The levels of contraction are 50 and 100 of maximal grip force 7 Click record and perform clench release cycles as listed below for 2 seconds each Release 25 of max release 50 of max release 75 of max release 100 of max Relase then clench as hard as possible 100 of max and try to hold this as long as possible 8 When finished click suspend 9 Review the data on the screen by using the various tools available Data Extraction 10 Click on Analyze Data 11 Click on the I Beam cursor button and highlight your entire data set 12 Click on Edit then Data Window then Copy Wave 13 Go to the bottom section and paste the data use Control V 14 Click on the Save icon and save the data to the KIN 460 folder labeled as your student ID Data Analysis and Writeup 1 For this writeup you will be turning in two graphs Both graphs should be scatterplots with lines and no dots and should report both the table and moodle data a Graph 1 Integrated EMG activity volts vs Time s b Graph 2 Clench Force n vs Time s c Both graphs should have Time on the x axis and Emg Force on the y axis with labels listing which line was table vs moodle data 2 How did your table data compare to the moodle data for the EMG and Force data times If the results differ give a couple reasons why these differences may have occurred 3 What is the Henneman size principle Name 2 other neural factors which contribute to muscular force production 1 June 12 1957 Weightlifter Paul Anderson Sets World Backlift Record Archives 1957 https 1957timecapsule wordpress com tag guiness book