Electrical Activity in Triceps and Biceps Brachii

Topic: Healthcare Research
Words: 1122 Pages: 4

Physiological Background

Analysis of muscle response using EMG can contribute to the development of rehabilitation programs for diseases associated with impaired muscle activity and to proceed the complex of exercises for sportsmen. To create a rehabilitation program, which usually includes exercises to restore muscles after illness or surgery, it is necessary to analyze the involvement of muscles in a particular movement, maximum activity, and its essential level for adequate recovery.

The level of increase in load can be analyzed to understand the appropriate threshold for muscle activity. A study of the biceps brachii muscle carried out by Kuthe et al. indicates a level of muscle fatigue for groups of trained and untrained patients by 5% (2018). According to Hussain et al. research, the triceps brachii can distribute the workload between the heads during times of fatigue, despite working independently during exercise at a normal pace (2020). The three TB heads act independently before fatigue and appear to work together after exhaustion (Hussain et al., 2019). The exercise performed in the later phase, the concentric contraction for endurance, indicates that fatigue in the muscles is 85% (Kumar et al., 2018). The nerves produce a high-frequency signal to achieve maximum contraction but cannot sustain the high-frequency signal for long periods, resulting in reduced muscle strength.

Surface electromyography is the primary method for detecting muscle fatigue because EMG signals provide more information about muscle activity.

The thesis of the study is that a sharply increasing load on the muscle involved in physical activity significantly increases the muscle response. The purpose of the experiment is to identify the relationship between the biceps and triceps brachii and the difference in response during the performance of different types of exercises.


During the first experiment, the activity of the triceps and biceps brachii muscles was analyzed during weight lifting of 1, 2, and 5 kg while performing elbow flexion by electromyogram. The greater the weight, the greater the response from both muscles was observed on EMG. The activity of the triceps muscle was higher than that of the biceps. In addition, there is a much more dramatic increase in triceps than biceps activity during weight gain. The second experiment was to measure the activity of the triceps and biceps muscles while lifting and holding a weight of 5 kg overhead. During this experiment, a much stronger response was obtained from the biceps brachii. Similarly, there was a sharp increase in biceps muscle activity as we approached the 110-second hold mark.

Table 1. Triceps Brachii concentric phase

Weight lifted Rep 1 (mV) Rep 2 (mV) Rep 3 (mV) Rep 4 (mV) Average
1 kg 0.51 0.46 0.57 0.34 0.47
2 kg 0.69 0.67 0.78 0.69 0.70
5kg 1.1 1.23 0.99 1.07 1.09

Table 2. Biceps brachii concentric phase

Weight lifted Rep 1 (mV) Rep 2 (mV) Rep 3 (mV) Rep 4 (mV) Average
1 kg 0.07 0.11 0.09 0.07 0.08
2 kg 0.18 0.14 0.16 0.13 0.15
5kg 0.26 0.34 0.38 0.37 0.33

Table 3. Triceps Brachii – isometric

Weight lifted – 5 kg EMG amplitude (mV)
5 seconds 0.04
10 seconds 0.04
15 seconds 0.05
110 seconds 0.09

Table 4. Biceps Brachii – isometric

Weight lifted – 5 kg EMG amplitude (mV)
5 seconds 0.23
10 seconds 0.24
15 seconds 0.27
110 seconds 0.44


During the first exercise, the fatigue of the triceps muscle, which is more involved during this action, to increase the load to 5 kg is about 50-70 percent. For the biceps muscle, which is less engaged in the exercise, fatigue is observed by 2-5 percent. During the second exercise, the triceps muscle was less involved; its fatigue was less than 1 percent. For a more involved biceps muscle, fatigue was 10-12%. Physiologically, the explanation for such early indicators can be found in the distribution of the joint load between the human body muscles.

The variety may occur since the load increased sharply in the first exercise; there were no noticeable changes in switching between 1 and 2 kg, but the impact of 5 kg was more than doubled. Less involved muscles in both experiments amounted to a negligible 1-2%. The difference in the second experiment – 12-70% – can be considered significant. This is explained by the difference between a sharply increasing load level and a prolonged exposure to the same load level. It can be concluded that the load on both muscles is less with prolonged exposure to a strong impact than with a single volume of this increase.

The data obtained are correlated with the results of previous studies. With similar exercises, fatigue scores correlate with the results obtained during the experiment – 5 percent agree, 50-70 percent are slightly lower than those obtained by other researchers 80. Perhaps the small difference is due to the longer rest period during the current experiment. Of particular interest is the study of the load distribution of the triceps muscle during muscle fatigue. The variable data comes from an underexplored mechanism for distributing the load between the heads, which normally operate independently. In general, the study of muscle response and muscle fatigue can significantly contribute to the development of rehabilitation and sports programs. Thus, the study shows that for a better result, the impact of the load should be quantitative, not qualitative.

Both experiments have significant limitations that can affect the objective result. First of all, for the study of the average muscle response, several participants are required of different levels of physical fitness. The study’s limitations are generally related to the EMG method’s limits. Only superficially located muscles are subject to examination, directly those on which the electrode can be placed. It is impossible to evaluate in isolation the contraction of the muscles of the second layer or small muscles included in the general muscle mass and provide a complete picture. The level of initial physical fitness also affects the conduct of the study. Perhaps, for the purity of the experiment and greater inductiveness of muscle load and response, the subject should be able to lift and hold the weight, not at 5 kg but 10. The weights in the first experiment could also be increased to achieve greater demonstrativeness.

Thus, the study revealed a relationship between increasing quantitative and qualitative workload. The load on the involved muscle turned out to be much stronger, and the muscle response increased with increasing load. Muscle fatigue was much higher when the load was increased to 5 kg, while fatigue was much lower during the long-term holding of this weight. The greatest research interest may be the load distribution of the triceps muscle of the shoulder in a state of fatigue. EMG research can contribute to the development of rehabilitation programs and training models for athletes.


Hussain, J., Sundaraj, K., Subramaniam, I.D. and Lam, C.K., 2019. Analysis of fatigue in the three heads of the triceps brachii during isometric contractions at various effort levels. Journal of musculoskeletal & neuronal interactions, 19(3), p.276-285. Web.

Hussain, J., Sundaraj, K., Subramaniam, I.D. and Lam, C.K., 2020. Muscle fatigue in the three heads of triceps brachii during intensity and speed variations of triceps push-down exercise. Frontiers in physiology, 11, p.112-125. Web.

Kumar, A., Pahuja, S.K. and Singh, A., 2018, December. Real time monitoring of muscle fatigue and muscle disorder of biceps brachii using Surface Electromyography (sEMG). In 2018 First International Conference on Secure Cyber Computing and Communication pp. 401-405). IEEE. Web.

Kuthe, C.D., Uddanwadiker, R.V. and Ramteke, A.A., 2018. Surface electromyography based method for computing muscle strength and fatigue of biceps brachii muscle and its clinical implementation. Informatics in Medicine Unlocked, 12, pp.34-43. Web.

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