UMass Amherst KIN 460 - Lab 3 MU recruitment (3 pages)

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Lab 3 MU recruitment



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Lab 3 MU recruitment

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Pages:
3
School:
University of Massachusetts Amherst
Course:
Kin 460 - Motor Control

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Motor unit recruitment KIN 460 Motor Control Lab Section 1 Lab 3 Principles of Motor Unit Recruitment and Muscular Force Production Motor unit recruitment and force production with and without fatigue Introduction Over the last week in class you have learned about how electrical signals lead to the contraction of muscular tissue excitation contraction coupling cycle The cells responsible for sending the descending signals to the muscle fibers are known as motor neurons Motor neurons have different properties that influence how muscle is activated They can be classified as slow fast fatigue resistant and fast fatigable the size of the cells in each class get progressively larger Because each cell type has different force producing capabilities larger cells produce more force than the smaller ones larger cells are progressively recruited as they are needed see the left panel in the figure above Because there are multiple ways to perform a movement movement poses a problem for the nervous system Control of movement is primarily organized hierarchically movement goals are formulated by higher brain areas while the activation of specific muscle fibers is determined by neural processes in the spinal cord Purpose To study the recruitment of motor units for force production To understand the changes in force production over time under different degrees of effort To understand how these force changes are related to the properties of the motor neurons that innervate the musculature involved To understand what electromyography EMG is and what the signal being recorded represents BEFORE BEGINNING THE LAB BUT AFTER READING THE INSTRUCTIONS AND GAINING A BETTER UNDERSTANDING OF THE NATURE OF THE EXPERIMENT DEVELOP A HYPOTHESIS FOR THIS EXPERIMENT AND WRITE IT DOWN THIS WILL BE INCLUDED IN YOUR LAB REPORT 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 Motor unit recruitment KIN 460 Motor Control Lab Section 1 2 Plug the electrode lead set for the forearm into channel 1 and the hand grip dynamometer into channel Attach the electrodes to the forearm The black lead ground should be on radial styloid the white lead negative should be on the flexor carpi radialis muscle and the red lead positive should be 3 inches from the white lead towards the radial styloid a To find the flexor carpi radialis of your dominant arm hold your arm down to your side and clinch your fist and curl your wrist towards your face flexing your wrist while clinching Your flexor carpi radialis and the ulnaris are the muscles of your forearm on the medial side about three fingers away from the crevice of your elbow When you clinch and curl the muscles should be firm 3 Start the Biopac program and load the lesson 2 titled EMG II 4 Type your name Calibration 1 Click calibrate set dynamometer down and click OK 2 After baseline calibration has been completed you will need



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