Muscle preactivity of anterior cruciate ligament-deficient and -reconstructed females during functional activities.
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| Title: | Muscle preactivity of anterior cruciate ligament-deficient and -reconstructed females during functional activities. |
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| Authors: | DeMont RG (AUTHOR), Lephart SM (AUTHOR), Giraldo JL (AUTHOR), Swanik CB (AUTHOR), Fu FH (AUTHOR) |
| Source: | Journal of Athletic Training (National Athletic Trainers' Association). Apr-Jun99, Vol. 34 Issue 2, p115-120. 6p. |
| Abstract: | Objective: Underlying the ability of the hamstrings to decrease tibial anterior shear is the time of firing in comparison with the quadriceps. This timing may be aided by neural programming during a planned or expected activity. It is theorized that individuals who have better programming ability will suffer fewer anterior cruciate ligament (ACL) injuries due to joint protection through muscular stabilization. A component of this dynamic restraint is the development of muscular tension before the knee is loaded. The objective of our study was to compare the muscular activity before footstrike in ACL-deficient (ACL-D), ACL-reconstructed (ACL-R), and control (C) females during functional activities. Design and Setting: Active females were divided into groups based on their ACL status. The study was conducted in a neuromuscular research laboratory. Subjects: Twenty-four female subjects (ACL-D = 6, ACLR = 12, C = 6). Measurements: Integrated electromyographic (IEMG) activity from the thigh (vastus medialis obliquus [VMO], vastus lateralis [VL], medial hamstring, and lateral hamstring) and leg (medial gastrocnemius and lateral gastrocnemius [LG]) and footswitch signals were recorded during downhill walking (15 degrees at 0.92 m/s), running (2.08 m/s), hopping, and landing from a step (20.3 cm). IEMG activity was normalized to the mean amplitude of the sample and analyzed for area and mean amplitude for 150 milliseconds before heelstrike. Side-to-side differences were determined by t tests, and separate one-way analyses of variance (ANOVA) were used to detect differences among the 3 groups for each muscle of each activity. Results: IEMG area side-to-side differences for the ACL-D group appeared in the LG (involved [11 = 36.4 +/- 19.7, uninvolved [U] = 60.1 +/- 23.6) during landing, in the VMO (I = 11.4 -+/- 3.8, U = 7.2 +/- 3.1) and VL (I = 13.3 +/- 2.7, U = 8.9 1.9) during running, and in the VMO (I = 9.2 +/- 4.2, U = 19.5 7.3) during downhill walking. IEMG mean amplitude side-to-side differences for the ACL-D group appeared in the LG (I = 79.7 +/- 30.3, U = 122.3 +/- 34.9) during downhill walking and in the VMO (I = 78.6 +/- 23.2, U = 45.8 +/- 18.9) during the run; IEMG mean amplitude side-to-side differences for the ACL-R group appeared in the LG (I = 74.7 +/- 40.0, U = 52.8 +/- 14.3) during the hop. The ACL-D group had higher IEMG means than control in the VL (ACL-D = 12.9 +/- 5.8, C = 7.1 +/- 3.9), but lower in the VMO (ACL-D = 9.2 +/- 4.2, C = 15.7 -3.6). Conclusions: The side-to-side differences of the ACL-D and ACL-R groups, as well as the group differences between ACL-D and control, suggest that different muscle activation strategies are used by females when performing different dynamic activities. Therefore, muscle unit differentiation may be the cause of our results. These changes appear to be reversed through surgery or the associated postoperative rehabilitation. [ABSTRACT FROM AUTHOR] |
| Copyright of Journal of Athletic Training (National Athletic Trainers' Association) is the property of National Athletic Trainers' Association and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Teacher Reference Center |
| FullText | Text: Availability: 0 |
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| Header | DbId: trh DbLabel: Teacher Reference Center An: 107206634 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Muscle preactivity of anterior cruciate ligament-deficient and -reconstructed females during functional activities. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22DeMont+RG%22">DeMont RG</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Lephart+SM%22">Lephart SM</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Giraldo+JL%22">Giraldo JL</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Swanik+CB%22">Swanik CB</searchLink> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Fu+FH%22">Fu FH</searchLink> (AUTHOR) – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Journal+of+Athletic+Training+%28National+Athletic+Trainers'+Association%29%22">Journal of Athletic Training (National Athletic Trainers' Association)</searchLink>. Apr-Jun99, Vol. 34 Issue 2, p115-120. 6p. – Name: Abstract Label: Abstract Group: Ab Data: Objective: Underlying the ability of the hamstrings to decrease tibial anterior shear is the time of firing in comparison with the quadriceps. This timing may be aided by neural programming during a planned or expected activity. It is theorized that individuals who have better programming ability will suffer fewer anterior cruciate ligament (ACL) injuries due to joint protection through muscular stabilization. A component of this dynamic restraint is the development of muscular tension before the knee is loaded. The objective of our study was to compare the muscular activity before footstrike in ACL-deficient (ACL-D), ACL-reconstructed (ACL-R), and control (C) females during functional activities. Design and Setting: Active females were divided into groups based on their ACL status. The study was conducted in a neuromuscular research laboratory. Subjects: Twenty-four female subjects (ACL-D = 6, ACLR = 12, C = 6). Measurements: Integrated electromyographic (IEMG) activity from the thigh (vastus medialis obliquus [VMO], vastus lateralis [VL], medial hamstring, and lateral hamstring) and leg (medial gastrocnemius and lateral gastrocnemius [LG]) and footswitch signals were recorded during downhill walking (15 degrees at 0.92 m/s), running (2.08 m/s), hopping, and landing from a step (20.3 cm). IEMG activity was normalized to the mean amplitude of the sample and analyzed for area and mean amplitude for 150 milliseconds before heelstrike. Side-to-side differences were determined by t tests, and separate one-way analyses of variance (ANOVA) were used to detect differences among the 3 groups for each muscle of each activity. Results: IEMG area side-to-side differences for the ACL-D group appeared in the LG (involved [11 = 36.4 +/- 19.7, uninvolved [U] = 60.1 +/- 23.6) during landing, in the VMO (I = 11.4 -+/- 3.8, U = 7.2 +/- 3.1) and VL (I = 13.3 +/- 2.7, U = 8.9 1.9) during running, and in the VMO (I = 9.2 +/- 4.2, U = 19.5 7.3) during downhill walking. IEMG mean amplitude side-to-side differences for the ACL-D group appeared in the LG (I = 79.7 +/- 30.3, U = 122.3 +/- 34.9) during downhill walking and in the VMO (I = 78.6 +/- 23.2, U = 45.8 +/- 18.9) during the run; IEMG mean amplitude side-to-side differences for the ACL-R group appeared in the LG (I = 74.7 +/- 40.0, U = 52.8 +/- 14.3) during the hop. The ACL-D group had higher IEMG means than control in the VL (ACL-D = 12.9 +/- 5.8, C = 7.1 +/- 3.9), but lower in the VMO (ACL-D = 9.2 +/- 4.2, C = 15.7 -3.6). Conclusions: The side-to-side differences of the ACL-D and ACL-R groups, as well as the group differences between ACL-D and control, suggest that different muscle activation strategies are used by females when performing different dynamic activities. Therefore, muscle unit differentiation may be the cause of our results. These changes appear to be reversed through surgery or the associated postoperative rehabilitation. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Journal of Athletic Training (National Athletic Trainers' Association) is the property of National Athletic Trainers' Association and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 6 StartPage: 115 Titles: – TitleFull: Muscle preactivity of anterior cruciate ligament-deficient and -reconstructed females during functional activities. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: DeMont RG – PersonEntity: Name: NameFull: Lephart SM – PersonEntity: Name: NameFull: Giraldo JL – PersonEntity: Name: NameFull: Swanik CB – PersonEntity: Name: NameFull: Fu FH IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 04 Text: Apr-Jun99 Type: published Y: 1999 Identifiers: – Type: issn-print Value: 10626050 Numbering: – Type: volume Value: 34 – Type: issue Value: 2 Titles: – TitleFull: Journal of Athletic Training (National Athletic Trainers' Association) Type: main |
| ResultId | 1 |
