The article titled “Localized muscle fatigue: review of three experiments,” retrieved from the Brazilian Journal of Physical Therapy gives an account of the measurement of localized muscle fatigue. Since fatigue plays a significant role in the human performance both physically as well as cognitively, it is essential to understand muscle fatigue in the scientific domain. As the author explains, fatigue refers to the reduction of energy or the rate of expenditure of muscle tissues (Kumar, 2006). An individual’s tissues experience mechanical fatigue as a result of repetitive or prolonged exertion. Similarly, muscles also experience fatigue, which might be contractile and physiological in nature. The journal article employs various methods, both objective and subjective in order to calculate the duration and magnitude of fatigue. The article explains various factors that are responsible for muscle fatigue as blood perfusion and level of oxygenation of the muscles (Kumar, 2006). Although there is no reliable measure of muscle fatigue, various indicators, such as electromyography, heart rate, visual analog scale and many others are possible choices to measure muscle fatigue.
In order to explain localized muscle fatigue, the article makes use of various equipment, such as EMG devices, heart rate monitor, infrared spectroscope, force monitor and load cell (Kumar, 2006). The author also includes various subjective measures, such as visual analog scale, RPE (Rate of Perceived Exertion) and BRDR (Body Part Discomfort Rating). The study conducted in the article makes use of healthy male and female subjects who do not have any kind of disorders. After measuring various indicators of the subjects in the resting state, the study requires them to perform certain activities, such as trunk extension, knee extension and elbow flexion (Kumar, 2006). The results obtained from these three experiments therefore aid to measure the magnitude of the muscle fatigue. The statistical methods used for the measurement of localized muscle fatigue are trend analysis, correlation analysis and linear mixed effects to study the forecast of oxygen intake, blood volume and EMG.
The overall result of the experiment is that there was a progression in muscle fatigue with the progression of time. The results obtained from the research also suggest muscle discomfort and force magnitude with the progression of muscle fatigue (Kumar, 2006). Simultaneously, it is also evident that there is a minimization in the amplitude of EMG post which follows an increment of dissipation with the cease of physical activity. Furthermore, the experiment also indicates the phenomenon for muscle contraction’s electrophysiological mechanism to remain intact until the end. Gender is a strong determinant for explaining the impact of muscle contraction (Kumar, 2006). It is understandable from the experiments that females generate less force when compared to men in terms of muscle contraction. Moreover, a larger muscle mass likely requires a greater amount of ATP and blood circulation for contraction.
The results obtained from the experiments conclude that it is better not to forecast the fatigue on the basis of a single variable as it is essential to consider a combination of a set of variable to obtain reliable information with regards to a specific muscle to measure the fatigue. The three experiments show that biceps brachii and erector spinae display similar results in a majority of the aspects (Kumar, 2006). Although visual analog score is a better variable in the case of lower contractions, it does not account for most of the variance. Furthermore, indexing a single variable with regards to localized muscle fatigue allows for various future implications. It also demands for reliable information with respect to muscle fatigue. The results attained in the experiment do not exhibit any strong correlation in terms of force though the amplitude of EMG following certain patterns of changes (Kumar, 2006).
Kumar, S. (2006). Localized muscle fatigue: review of three experiments. Brazilian Journal of Physical Therapy, 10(1), 9-28.