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Knee joint angle affects EMG-force relationship in the vastus intermedius muscle.
J Electromyogr Kinesiol. 2013 Dec; 23(6):1406-12.JE

Abstract

It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P < 0.05). Comparing the normalized EMG among the four QF synergists, a significantly lower normalized EMG was observed in the VI at 150° as compared with the other three QF muscles (P < 0.05). These results suggest that the EMG-force relationship of the four QF synergists shifted downward at an extended knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles.

Authors+Show Affiliations

Graduate School of Education and Human Development, Nagoya University, Japan; Japan Society for the Promotion of Science, Japan. Electronic address: a-saito@nagoya-u.jp.No affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

24075525

Citation

Saito, Akira, and Hiroshi Akima. "Knee Joint Angle Affects EMG-force Relationship in the Vastus Intermedius Muscle." Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology, vol. 23, no. 6, 2013, pp. 1406-12.
Saito A, Akima H. Knee joint angle affects EMG-force relationship in the vastus intermedius muscle. J Electromyogr Kinesiol. 2013;23(6):1406-12.
Saito, A., & Akima, H. (2013). Knee joint angle affects EMG-force relationship in the vastus intermedius muscle. Journal of Electromyography and Kinesiology : Official Journal of the International Society of Electrophysiological Kinesiology, 23(6), 1406-12. https://doi.org/10.1016/j.jelekin.2013.08.009
Saito A, Akima H. Knee Joint Angle Affects EMG-force Relationship in the Vastus Intermedius Muscle. J Electromyogr Kinesiol. 2013;23(6):1406-12. PubMed PMID: 24075525.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Knee joint angle affects EMG-force relationship in the vastus intermedius muscle. AU - Saito,Akira, AU - Akima,Hiroshi, Y1 - 2013/09/04/ PY - 2013/04/09/received PY - 2013/07/31/revised PY - 2013/08/28/accepted PY - 2013/10/1/entrez PY - 2013/10/1/pubmed PY - 2014/7/6/medline KW - Isometric contraction KW - Knee extension KW - Knee joint angle KW - Muscle length KW - Quadriceps femoris SP - 1406 EP - 12 JF - Journal of electromyography and kinesiology : official journal of the International Society of Electrophysiological Kinesiology JO - J Electromyogr Kinesiol VL - 23 IS - 6 N2 - It is not understood how the knee joint angle affects the relationship between electromyography (EMG) and force of four individual quadriceps femoris (QF) muscles. The purpose of this study was to examine the effect of the knee joint angle on the EMG-force relationship of the four individual QF muscles, particularly the vastus intermedius (VI), during isometric knee extensions. Eleven healthy men performed 20-100% of maximal voluntary contraction (MVC) at knee joint angles of 90°, 120° and 150°. Surface EMG of the four QF synergists was recorded and normalized by the root mean square during MVC. The normalized EMG of the four QF synergists at a knee joint angle of 150° was significantly lower than that at 90° and 120° (P < 0.05). Comparing the normalized EMG among the four QF synergists, a significantly lower normalized EMG was observed in the VI at 150° as compared with the other three QF muscles (P < 0.05). These results suggest that the EMG-force relationship of the four QF synergists shifted downward at an extended knee joint angle of 150°. Furthermore, the neuromuscular activation of the VI was the most sensitive to change in muscle length among the four QF synergistic muscles. SN - 1873-5711 UR - https://www.unboundmedicine.com/medline/citation/24075525/Knee_joint_angle_affects_EMG_force_relationship_in_the_vastus_intermedius_muscle_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S1050-6411(13)00216-2 DB - PRIME DP - Unbound Medicine ER -