Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum
Introduction: Onset and offset activation of lower limb and trunk muscles may change the knee with genu varum during landing. These motor control strategies can be different from those in healthy subjects and contribute to more injuries in lower extremities. This study aimed to compare the delay tim...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Tehran University of Medical Sciences
2020-08-01
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| Series: | Journal of Modern Rehabilitation |
| Subjects: | |
| Online Access: | https://jmr.tums.ac.ir/index.php/jmr/article/view/298 |
| _version_ | 1828235149323534336 |
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| author | Mahboobeh Azizi Khosrow Khademi Mehri Ghasemi Alireza Akbarzadegan |
| author_facet | Mahboobeh Azizi Khosrow Khademi Mehri Ghasemi Alireza Akbarzadegan |
| author_sort | Mahboobeh Azizi |
| collection | DOAJ |
| description | Introduction: Onset and offset activation of lower limb and trunk muscles may change the knee with genu varum during landing. These motor control strategies can be different from those in healthy subjects and contribute to more injuries in lower extremities. This study aimed to compare the delay time of the onset activity of the abdominal and lower limb muscles in the specific landing task.
Materials and Methods: Ten females with genu varum deformity and ten females with normal knee participated in this case-control study. Genu varum deformity was measured by a camera capturing goniometer. The subjects were informed to land by preferred lower limb from a table (30 cm high) on a force plate. Vertical Ground Reaction Force (VGRF) was measured to clarify the onset of the landing task. Surface Electromyography (sEMG) of transverse abdominal/int. oblique (TA/IO), Vastus Medialis (VM), Vastus Lateralis (VL), Lateral Gastrocnemius (LG), and medial gastrocnemius (MG) muscles were recorded during landing. The difference between the onset activity of the above muscles and onset of VGRF was calculated as delay times and compared between muscles and between two groups. Also, the offset of activities and the intensity of muscle activation (normalized RMS) were compared between the two groups.
Results: Lower limb and trunk muscles showed significantly different onset of activities in the genu varum group (P<0.05), whereas there was no significant difference in the onset of muscle activities in the healthy group. Results indicated significant differences between two groups in TA/IO, LG, and MG muscles and the genu varum group had longer delay time for motor control strategy (especially ankle strategy) in the landing task. Offset time of all muscles in the genu varum and healthy subjects had a significant difference between muscles, especially in gastrocnemius muscles (P<0.05). Also, there were significant changes between the two groups in LG and MG muscles (P<0.05). Normalized muscle activities (nRMS) generally indicated an increase in muscle activation of genu varum subjects (TA/IO, LG, MG) compared with the normal subjects (P<0.05).
Conclusion: Motor control strategies in landing task is different in the genu varum group due to changes in biomechanics and properties of the knee joint. This variation may be due to changes in proprioception afferent pathways around the knee joint. An increase in muscle activation, delay, and offset time of muscle activities in these subjects, indicated that an increase in the degree of freedom may change motor control strategies. Internal anticipation and postural adjustment of the landing task in these subjects need more motor unit recruitment (an increase in nRMS). This deformity in the knee joint might affect some activities and possibly cause knee changes such as osteoarthritis. |
| first_indexed | 2024-04-12T20:07:47Z |
| format | Article |
| id | doaj.art-3a9bf03ca7374788b51c16e11455e6b7 |
| institution | Directory Open Access Journal |
| issn | 2538-385X 2538-3868 |
| language | English |
| last_indexed | 2024-04-12T20:07:47Z |
| publishDate | 2020-08-01 |
| publisher | Tehran University of Medical Sciences |
| record_format | Article |
| series | Journal of Modern Rehabilitation |
| spelling | doaj.art-3a9bf03ca7374788b51c16e11455e6b72022-12-22T03:18:19ZengTehran University of Medical SciencesJournal of Modern Rehabilitation2538-385X2538-38682020-08-01142Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu VarumMahboobeh Azizi0Khosrow Khademi1Mehri Ghasemi2Alireza Akbarzadegan3Department of Physiotherapy, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.Department of Physiotherapy, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.Department of Physiotherapy, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.Department of Physiotherapy, School of Rehabilitation, Shahid Beheshti University of Medical Sciences, Tehran, Iran.Introduction: Onset and offset activation of lower limb and trunk muscles may change the knee with genu varum during landing. These motor control strategies can be different from those in healthy subjects and contribute to more injuries in lower extremities. This study aimed to compare the delay time of the onset activity of the abdominal and lower limb muscles in the specific landing task. Materials and Methods: Ten females with genu varum deformity and ten females with normal knee participated in this case-control study. Genu varum deformity was measured by a camera capturing goniometer. The subjects were informed to land by preferred lower limb from a table (30 cm high) on a force plate. Vertical Ground Reaction Force (VGRF) was measured to clarify the onset of the landing task. Surface Electromyography (sEMG) of transverse abdominal/int. oblique (TA/IO), Vastus Medialis (VM), Vastus Lateralis (VL), Lateral Gastrocnemius (LG), and medial gastrocnemius (MG) muscles were recorded during landing. The difference between the onset activity of the above muscles and onset of VGRF was calculated as delay times and compared between muscles and between two groups. Also, the offset of activities and the intensity of muscle activation (normalized RMS) were compared between the two groups. Results: Lower limb and trunk muscles showed significantly different onset of activities in the genu varum group (P<0.05), whereas there was no significant difference in the onset of muscle activities in the healthy group. Results indicated significant differences between two groups in TA/IO, LG, and MG muscles and the genu varum group had longer delay time for motor control strategy (especially ankle strategy) in the landing task. Offset time of all muscles in the genu varum and healthy subjects had a significant difference between muscles, especially in gastrocnemius muscles (P<0.05). Also, there were significant changes between the two groups in LG and MG muscles (P<0.05). Normalized muscle activities (nRMS) generally indicated an increase in muscle activation of genu varum subjects (TA/IO, LG, MG) compared with the normal subjects (P<0.05). Conclusion: Motor control strategies in landing task is different in the genu varum group due to changes in biomechanics and properties of the knee joint. This variation may be due to changes in proprioception afferent pathways around the knee joint. An increase in muscle activation, delay, and offset time of muscle activities in these subjects, indicated that an increase in the degree of freedom may change motor control strategies. Internal anticipation and postural adjustment of the landing task in these subjects need more motor unit recruitment (an increase in nRMS). This deformity in the knee joint might affect some activities and possibly cause knee changes such as osteoarthritis.https://jmr.tums.ac.ir/index.php/jmr/article/view/298Surface electromyographyGenu varumLeg drop landingMotor control |
| spellingShingle | Mahboobeh Azizi Khosrow Khademi Mehri Ghasemi Alireza Akbarzadegan Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum Journal of Modern Rehabilitation Surface electromyography Genu varum Leg drop landing Motor control |
| title | Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum |
| title_full | Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum |
| title_fullStr | Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum |
| title_full_unstemmed | Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum |
| title_short | Changes in Muscle Strategies During Landing Task in Subjects With and Without Knee Genu Varum |
| title_sort | changes in muscle strategies during landing task in subjects with and without knee genu varum |
| topic | Surface electromyography Genu varum Leg drop landing Motor control |
| url | https://jmr.tums.ac.ir/index.php/jmr/article/view/298 |
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