Earticle

초록

영어

This study compared neuromuscular characteristics, force steadiness (FS), and ultrasound-derived muscle texture features of the calf muscles between competitive bodybuilders (BB, n = 15) and non-trained controls (CON, n = 14) during plantarflexion across multiple contraction intensities. Maximal voluntary isometric contraction (MVC) torque and FS were assessed using a torque sensor, while high-density surface electromyography was used to analyze motor unit (MU) firing rate, recruitment threshold, and derecruitment threshold in the medial gastrocnemius (GM), lateral gastrocnemius (GL), and soleus (SOL). Intermuscular coherence among MU spike trains was quantified across multiple frequency bands. Ultrasound imaging was employed to assess muscle thickness, echo intensity (EI), and gray-level co-occurrence matrix (GLCM)-derived texture features. The BB group demonstrated significantly higher normalized MVC compared with the CON group (p < 0.01). FS was significantly lower in the CON group at 30% MVC (p < 0.05), whereas the BB group exhibited reduced FS at 70% MVC (p < 0.01). Ultrasound analysis revealed lower EI and distinct GLCM-derived texture features in GM and GL in the BB group (p < 0.01), with no significant differences observed in SOL. MUAP amplitude was lower in the BB group in GM at 30% and 50% MVC and in GL at 50% MVC (p < 0.05). Derecruitment thresholds were also lower in the BB group in GM at 70% MVC and in SOL at 50% and 70% MVC (p < 0.05). Although overall muscular synchronization did not differ between groups, the BB group exhibited significantly higher intermuscular coherence in the β-band for GM/SOL at 50% MVC, and in the α- and β-bands for GL/SOL as well as the δ-band for GM/GL at 70% MVC (p < 0.05). These findings indicate that long-term weight training is associated with intensity-dependent neuromuscular adaptations characterized by altered motor unit behavior and intermuscular coordination during plantarflexion.

저자

• Jae-Sung Lee [ Sports Medicine Lab., Department of Physical Education, Kyungpook National University, Daegu, Korea ]
• Maeng-Kyu Kim [ Sports Medicine Lab., Department of Physical Education, Kyungpook National University, Daegu, Korea ] Corresponding Author

참고문헌

발행기관

간행물

표지보기 관심저널 등록

• 간행물명

  한국운동재활학회 학술대회

• 간기

  부정기

• 수록기간

  2011~2026

• 십진분류

  KDC 517 DDC 613