Method and apparatus for measuring muscle fatigue
First Claim
1. A method for measuring muscle fatigue, in which electromyographic (EMG) signals measured from a muscle are used to determine the fatigue level of the muscle, the method comprising the steps of:
- receiving an EMG input signal x(t) from electrodes attached to the muscle to be analyzed;
sampling said input signal to form a sequence of discrete signal values xi ;
calculating the difference Δ
xi between several pairs of successive sample values xi and xi·
i ;
depending on the signal of the calculated difference Δ
xi, adding cumulatively the sampled values xi in a first accumulator means (A1) if said difference is positive, and in a second accumulator means (B1) if said difference is negative, and said difference values Δ
xi in a third accumulator means (C);
obtaining separate sequences of quotients between the values representative of the output from said third accumulator means and values representative of the outputs from said first and second accumulator means, respectively;
obtaining for each of said sequences a single quotient having a weighted value representative of a number of said quotients; and
multiplying the obtained weighted values with each other in order to obtain an index indicative of fatigue in said muscle.
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Abstract
A method and an apparatus for measuring muscle fatigue is disclosed, in which electromyographic (EMG) signals are measured from a muscle in order to determine the fatigue level of the muscle. The invention comprises the steps of: receiving an EMG input signal from electrodes attached to the muscle to be analyzed; sampling said input signal to a sequence of discrete signal values; calculating the difference between several pairs of successive sample values; depending on the sign of the calculated difference, adding cumulatively the sampled values in a first or second accumulator means, and said difference values in a third accumulator means; obtaining separate sequences of quotients between the values representative of the output from said third accumulator means and values representative of the outputs from said first and second accumulator means, respectively; obtaining for each of said sequences a single quotient having a weighted value representative of a number of said quotients; multiplying the obtained weighted values with each other in order to obtain an index indicative of fatigue during said time period in said muscle.
16 Citations
14 Claims
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1. A method for measuring muscle fatigue, in which electromyographic (EMG) signals measured from a muscle are used to determine the fatigue level of the muscle, the method comprising the steps of:
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receiving an EMG input signal x(t) from electrodes attached to the muscle to be analyzed; sampling said input signal to form a sequence of discrete signal values xi ; calculating the difference Δ
xi between several pairs of successive sample values xi and xi·
i ;depending on the signal of the calculated difference Δ
xi, adding cumulatively the sampled values xi in a first accumulator means (A1) if said difference is positive, and in a second accumulator means (B1) if said difference is negative, and said difference values Δ
xi in a third accumulator means (C);obtaining separate sequences of quotients between the values representative of the output from said third accumulator means and values representative of the outputs from said first and second accumulator means, respectively; obtaining for each of said sequences a single quotient having a weighted value representative of a number of said quotients; and multiplying the obtained weighted values with each other in order to obtain an index indicative of fatigue in said muscle. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. Apparatus for measuring muscle fatigue, in which electromyographic (EMG) signals from a muscle are measured to determine the fatigue level of the muscle, the apparatus comprising:
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input means (1) adapted to receive an EMG input signal x(t) from electrodes attached to the muscle to be analyzed and to sample said input signal to form a sequence of discrete signal values xi ; difference calculating means (S) for computing the difference Δ
xi between several pairs of successive sample values xi and xi·
1 ;control logic means (3) for determining the sign of said difference Δ
xi and for providing the signals necessary for controlling the EMG measuring apparatus;first, second and third accumulator means (A1, B1, C) for selectively receiving, depending on the sign of the calculated difference Δ
xi, sampled values xi and said difference values Δ
xi ;dividing means (D1, E1) for computing separate sequences of quotients between values representative of the output from said third accumulator means and values representative of the output from one of said first and second accumulator means, respectively; statistical analyzing means (F,G) for obtaining for each of said sequences a single weighted quotient value representative of a number of said quotients; and multiplying means (H) for multiplying the obtained weighted values with each other in order to obtain an index indicative of fatigue during said time period in said muscle. - View Dependent Claims (9, 10, 11, 12, 13, 14)
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Specification