Question

EMg is not a good tool for measuring?

-when a muscle turns on and off

-the amount if load lifted in pounds

-the number of active motor units

-muscle fatigue

Answer 1

ELECTROMYOGRAPHY IS THE STUDY OF ELECTRICAL ACTIVITY OF A MUSCLE AND ELECTROMYOGRAM IS THE GRAPHICAL REPRESENTATION OF THE ELECTRICAL ACTIVITY OF THE MUSCLE.

FROM THE ABOVE OPTIONS:

1. ELECTROMYOGRAPHY CAN BE USED TO CHECK THE ACTIVATION OF A MUSCLE.IT RECORDS BOTH, THE VOLUNTARY ACTIVITY AND RESTING ACTIVITY OF THE MUSCLE.

2. MUSCLE FORCE CAN BE MEASURED AND IS IN CORELATION WITH THE MAXIMUM VOLUNTARY CONTRACTION(MVC). BUT IT SHOULD BE NOTED THAT THIS MCV CAN BE RECORDED ONLY FROM THE MUSCLE FIBRES WHO ARE IN CLOSE PROXIMITY TO THE SURFACE. SO, THE MEASUREMENT OF THE AMOUNT OFMUSCLE FORCE APPLIED IS STILL A TOPIC OF DEBATE.

3. ONE MOTOR UNIT CONSIST OF ONE MOTOR NEURON AND THE MUSCLE FIBRES ASSOCIATED WITH IT. WHEN THE ACTION POTENTIAL IS GENERATED, IT IS CARIED DOWN TO THE NEUROMUSCULAR JUNCTION. FROM THE NEUROMUSCULAR JUNCTION IT IS DISTRIBUTED/ TRANSMITTED IN ALL THE MUSCLE FIBRES ASSOCIATED WITH THAT PARTICULAR MOTOR NEURON. THE SUM OF THIS ELECTRICAL ACTIVITY IS KNOWN AS MOTOR UNIT ACTION POTENTIAL. THE ELECTRICAL ACTIVITY OF ALL THE ACTIVATED MOTOR UNITS ( WHETHER SINGLE OR MULTIPLE MOTOR UNITS) IS RECORDED IN THE ELECTROMYOGRAPHY.

4. THE EMG IS A GOOD TOOL FOR MEASURING THE AMOUNT OF MUSCLE FATIGUE. THE CHANGES IN THE ELECTROMYOGRAM ( INCREASE IN AMPLITUDE AND DURATION OF MUSCLE ACTION POTENTIAL) INDICATES THE AMOUNT OF MUSCLE FATIGUE.

SO, OPTION NO.2 IS CORRECT FOR THIS QUESTION.