TY - JOUR AU - Samanta, Abir AU - Mukherjee, Sabyasachi PY - 2021/03/25 Y2 - 2024/03/29 TI - Assessment of Myoelectric Manifestations of Muscle Fatigue During Repetitive Isometric Voluntary Contraction in Boys Aged 12-14 JF - Physical Education Theory and Methodology JA - Teor. metod. fiz. vihov. VL - 21 IS - 1 SE - Original Scientific Articles DO - 10.17309/tmfv.2021.1.07 UR - https://tmfv.com.ua/journal/article/view/1450 SP - 50-60 AB - <p><strong>Aim: </strong>To study the peculiarity of electromyography signal characteristics alternation using different sEMG parameters during repetitive voluntary isometric fatiguing contraction in adolescent boys.<span class="Apple-converted-space">&nbsp;</span></p><p><strong>Materials and methods.</strong> 12 subjects with height 148.75 ± 10 cm; Mass 38.9 ± 7.9 kg; age – 12 to 14 years were recruited. The sEMG signal alteration of external oblique, rectus abdominis, erector spinae muscles during a fatiguing plank were analyzed. A separate one-way repeated measures ANOVA was used to test the statistical significance of task time and electromyography parameters of the global core muscle in the pre-, during- and post-fatigue plank test. One-way Friedman ANOVA was applied for Shapiro-Wilk p &lt; 0.05. The Pearson product-moment correlation coefficient with bivariate linear regressions analysis was performed between the pre-pre fatigue and post-post fatigue amplitude mean and standard deviation values. The Spearman correlation coefficient between amplitude and endurance time both in the pre- and post-fatigue state was conducted.<span class="Apple-converted-space">&nbsp;</span></p><p><strong>Results.</strong> The mean value of rectified amplitude increased (p &lt; 0.05) for all muscles, the standard deviation of amplitude and total spectral power increased significantly (p &lt; 0.05) for all muscles except the erector spinae muscle (p &gt; 0.05). The power at normalized low frequency significantly changed (p = 0.05) in the erector spinae muscle. A significant change in normalized low frequency for agonist/synergist (p = 0.02) and agonist/antagonist muscles (p = 0.05) was observed. The average amplitude value had a significant positive and linear relationship with the amplitude variability both in the pre- to post-fatigue state, except the erector spinae muscle. The time to task failure was not correlated (p &gt; 0.05) with the sEMG amplitude.<span class="Apple-converted-space">&nbsp;</span></p><p><strong>Conclusions.</strong> Increased sEMG amplitude resulted mainly from rapid additional motor unit recruitment and rate coding during muscle fatigue. The reduction of conduction velocity might affect the spectral power with a spectral shift towards low-frequency. Increased variability, agonist/antagonist co-activity during fatiguing contraction might extend the holding time. The postural fatiguing task/plank increases multiarticular joint function by involving several joints and muscles, increases variability in the contribution of synergist muscles. This factor provides an intuitive explanation about the absence of a relationship between endurance time and sEMG amplitude changes.</p> ER -