Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction
This study investigated the effects of knee joint angle on muscle activation, exerted torque, and whether the knee angle affects the muscle activation–torque ratio. Nine healthy adult male participants participated in the study. They performed maximal voluntary isometric contraction (MVIC) at six (8...
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| Format: | Article |
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MDPI AG
2022-10-01
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| Series: | Biology |
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| Online Access: | https://www.mdpi.com/2079-7737/11/10/1490 |
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| author | Filip Kukić Vladimir Mrdaković Aleksandar Stanković Duško Ilić |
| author_facet | Filip Kukić Vladimir Mrdaković Aleksandar Stanković Duško Ilić |
| author_sort | Filip Kukić |
| collection | DOAJ |
| description | This study investigated the effects of knee joint angle on muscle activation, exerted torque, and whether the knee angle affects the muscle activation–torque ratio. Nine healthy adult male participants participated in the study. They performed maximal voluntary isometric contraction (MVIC) at six (80°, 90°, 100°, 110°, 120°, and 130°) different knee joint angles (i.e., angles between the thigh and shin bones). Their maximal torque was assessed utilizing an isokinetic chair, while their muscle activation (root mean square [RMS]) was assessed using an eight-channel single differential surface EMG sensor. For the purposes of the torque–knee angle relationship and muscle activation–knee angle relationship, the torque and RMS were normalized relative to the maximal value obtained by each participant. To evaluate the muscle activation–torque ratio in function of knee angle, RMS was normalized relative to the corresponding torque obtained at each knee angle. Repeated measure analysis of variance was used to investigate the effects of knee angle on muscle activation, torque, and muscle activation–torque ratio. There was a significant effect of knee joint angle on normalized torque (F = 27.521, <i>p</i> < 0.001), while the activation of vastus lateralis and vastus medialis remained unchanged. The changes in knee angle affected the muscle activation–torque ratio of vastus lateralis (Chi-square = 16.246, <i>p</i> = 0.006) but not the vastus medialis. These results suggest that knee joint angles from 80° to 130° provide a stable milieu for muscle electrification, while mechanical factor such as knee joint angle (i.e., lever arm length) affect the torque output when one needs to contract quadriceps maximally during the isometric contraction. |
| first_indexed | 2024-03-09T20:39:34Z |
| format | Article |
| id | doaj.art-1986ff1d073e4924a2e1a603b1f3fe75 |
| institution | Directory Open Access Journal |
| issn | 2079-7737 |
| language | English |
| last_indexed | 2024-03-09T20:39:34Z |
| publishDate | 2022-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Biology |
| spelling | doaj.art-1986ff1d073e4924a2e1a603b1f3fe752023-11-23T23:00:26ZengMDPI AGBiology2079-77372022-10-011110149010.3390/biology11101490Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric ContractionFilip Kukić0Vladimir Mrdaković1Aleksandar Stanković2Duško Ilić3Police Sports Education Center, Abu Dhabi Police, Abu Dhabi 253, United Arab EmiratesFaculty of Sport and Physical Education, University of Belgrade, 11030 Belgrade, SerbiaFaculty of Sport and Physical Education, University of Belgrade, 11030 Belgrade, SerbiaFaculty of Sport and Physical Education, University of Belgrade, 11030 Belgrade, SerbiaThis study investigated the effects of knee joint angle on muscle activation, exerted torque, and whether the knee angle affects the muscle activation–torque ratio. Nine healthy adult male participants participated in the study. They performed maximal voluntary isometric contraction (MVIC) at six (80°, 90°, 100°, 110°, 120°, and 130°) different knee joint angles (i.e., angles between the thigh and shin bones). Their maximal torque was assessed utilizing an isokinetic chair, while their muscle activation (root mean square [RMS]) was assessed using an eight-channel single differential surface EMG sensor. For the purposes of the torque–knee angle relationship and muscle activation–knee angle relationship, the torque and RMS were normalized relative to the maximal value obtained by each participant. To evaluate the muscle activation–torque ratio in function of knee angle, RMS was normalized relative to the corresponding torque obtained at each knee angle. Repeated measure analysis of variance was used to investigate the effects of knee angle on muscle activation, torque, and muscle activation–torque ratio. There was a significant effect of knee joint angle on normalized torque (F = 27.521, <i>p</i> < 0.001), while the activation of vastus lateralis and vastus medialis remained unchanged. The changes in knee angle affected the muscle activation–torque ratio of vastus lateralis (Chi-square = 16.246, <i>p</i> = 0.006) but not the vastus medialis. These results suggest that knee joint angles from 80° to 130° provide a stable milieu for muscle electrification, while mechanical factor such as knee joint angle (i.e., lever arm length) affect the torque output when one needs to contract quadriceps maximally during the isometric contraction.https://www.mdpi.com/2079-7737/11/10/1490electromyographymotor controlF–L relationshipRMS–F relationshiprelative muscle force |
| spellingShingle | Filip Kukić Vladimir Mrdaković Aleksandar Stanković Duško Ilić Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction Biology electromyography motor control F–L relationship RMS–F relationship relative muscle force |
| title | Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction |
| title_full | Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction |
| title_fullStr | Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction |
| title_full_unstemmed | Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction |
| title_short | Effects of Knee Extension Joint Angle on Quadriceps Femoris Muscle Activation and Exerted Torque in Maximal Voluntary Isometric Contraction |
| title_sort | effects of knee extension joint angle on quadriceps femoris muscle activation and exerted torque in maximal voluntary isometric contraction |
| topic | electromyography motor control F–L relationship RMS–F relationship relative muscle force |
| url | https://www.mdpi.com/2079-7737/11/10/1490 |
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