QUANTIFICATION OF MUSCLE WORKLOAD BASED ON ELECTROMYOGRAPHIC SIGNALS IN THE USE OF A SUSPENDED BACKPACK SYSTEM

• Main Author: Kurnia, Megasari
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/52003
• Institution: Institut Teknologi Bandung

The use of backpacks is very commonly utilized by various groups, from children to adults. Backpacks are used as containers to ease us in carrying the equipment needed in our daily activities. Activities such as walking or running while carrying a backpack with a load will cause an impact force which results in a greater loading force. The greater the load of the backpack that is imposed on the muscles, the greater the chance of fatigue caused by the muscles withstand the load given by the backpack. Thus, it is necessary to design and develop a backpack with a suspension with the aim of minimizing the user's muscle fatigue. The effect of fatigue is seen based on quantitative measurements. The quantitative value of fatigue is known based on electromyography (EMG) measurements. Electromyography (EMG) measurements are conducted to evaluate muscle function from the use of a suspension backpack, by recording the electrical activity generated by skeletal muscles. The aim is to determine the difference in muscle response from using a backpack with suspension and a backpack without suspension and to evaluate the muscle function that causes fatigue from the loading aspect of the backpack. Thus, it proves that the test of using a backpack with a suspension can minimize the user's muscle fatigue. Subjects involved in this study were limited to the age of 20-30 years men provided the subjects were in good health. Measurement of the EMG signal was carried out on the trapezius and erector spinae muscles. This research scheme was conducted by giving instructions to the subjects to walk and carry a suspension backpack and a backpack without suspension with a load of 0 kg, 5 kg, and 10 kg respectively at a treadmill speed of 3 km / h and 5 km / h. The signal was measured using an electromyogram measuring instrument with a count frequency of 2000 Hz. The measured EMG signal was conditioned through the preprocessing stage and eliminates noise and artifacts. The decomposition of the EMG signal contaminated with noise and artifacts was carried out using the discrete wavelet transform (DWT) method. The analysis of the two muscles involved in the load-bearing process was performed to obtain quantitative parameters in evaluating muscle fatigue. Quantitative parameters are obtained from feature extraction to obtain a smoothing data base for the time-frequency spectrogram to obtain the mean spectral power and median frequency values. Feature extraction was done using computational engineering. Based on the EMG signal feature in subjects using a backpack with suspension and a backpack without a suspension, it was compared to determine the significant difference of backpack stiffness with the load factor and its effect on the muscles generated from each backpack based on muscle contraction. Muscle contraction is represented based on the time-frequency spectrogram of the movement pattern while walking with the backpack on the EMG signal in the trapezius and erector spinae muscles. Feature extraction in the time-frequency domain was conducted by analyzing the EMG signal pattern and comparing the EMG signal in the use of a suspended backpack and a backpack without a suspension. EMG signal parameters used in identifying muscle contraction, namely: average spectral power and median frequency. The analysis of the muscle fatigue level evaluation based on the average spectral power of the backpack use with suspension and a backpack without a suspension shows a significant difference at the speed of 3 km / h with a load of 10 kg for the two muscle points. However, for a walking speed of 5 km / hour the average spectral power values are significant at 5 kg and 10 kg loads for the trapezius muscles, and for the erector spinae muscles it is significant for all load variables of 0 kg, 5 kg, and 10 kg. The analysis for the evaluation of muscle function that causes fatigue based on the median frequency of using a suspended backpack and a backpack without a suspension shows that the median frequency in a suspension backpack and a backpack without a suspension tends to be the same for the trapezius muscles for all load variables at speeds of 3km / hr or 5km / hr. However, in the erector spinae muscle the median frequency value shows a significant difference in the load of 10 kg for a speed of 3 km / hour. Whereas at a speed of 5 km / hour, the median frequency value of the erector spinae muscle shows a significant difference at 5 kg and 10 kg loads. The difference in walking speed and the load applied to the backpack will greatly affect the performance of the backpack with a suspension and the effect of fatigue on the muscles. In addition, the measured muscle point can affect the analysis of the level of significance depending on the characteristics of the muscle. Based on the results of this identification, it can be used as feedback for backpack manufacturers who use suspension technology to minimize the effect of fatigue on muscles after using a suspended backpack.