Normalization of EMG Signals: Optimal MVC Positions for the Lower Limb Muscle Groups in Healthy Subjects

• Published in: Journal of medical and biological engineering Vol. 43; no. 2; pp. 195 - 202
• Main Authors: Avdan, Goksu, Onal, Sinan, Smith, Bryan K.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.04.2023; Springer Nature B.V
• Subjects: Ankle; Biological Techniques; Biomedical and Life Sciences; Biomedical Engineering and Bioengineering; Biomedical Engineering/Biotechnology; Biomedicine; Electromyography; Knee; Original Article; Prone position; Regenerative Medicine/Tissue Engineering; Sitting position; Variance analysis; Maximum voluntary contraction; Electromyography; Normalization; Lower limb muscles
• ISSN: 1609-0985; 2199-4757
• DOI: 10.1007/s40846-023-00782-3

Purpose A comprehensive investigation of various maximum voluntary contraction (MVC) positions to determine the optimal positions for vastus lateralis (VL), biceps femoris (BF), gastrocnemius lateralis (GL), and tibialis anterior (TA). Methods Twelve participants performed total of seventeen MVC positions for major lower limb muscle groups (VL, BF, GL, and TA). Neuromuscular activities were recorded by surface electromyography. Signals were smoothed by root mean square (RMS). Each MVC level were expressed as a percentage of MVC (% MVC). Statistical differences were measured with a one-way repeated measures analysis of variance and a Tukey’s HSD ( p  < 0.05). Results Optimal MVC positions were found as follows: (i) VL: the combination of knee extension at 70° and 90° flexed knee in sitting position; (ii) BF: the combination of knee flexion at 30°, 45°, and 60° flexed knee in prone position; (iii) GL: unipedal standing position; (iv) TA: the combination of dorsiflexion in sitting position and ankle neutral, in standing position and ankle 110°, and in standing position and ankle 70°. Conclusion This study confirms that multiple positions were needed to elicit the maximal MVC values for VL, BF, and TA. For GL, single MVC position should be performed to elicit the maximal MVC.