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Quadriceps EMG in Open and Closed Kinetic Chain Tasks in Women With Patellofemoral Pain.
Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.
Umeå University, Faculty of Medicine, Department of Radiation Sciences, Radiation Physics.ORCID iD: 0000-0003-3363-7414
Umeå University, Faculty of Medicine, Department of Community Medicine and Rehabilitation, Physiotherapy.ORCID iD: 0000-0002-0366-4609
2007 (English)In: Journal of motor behavior, ISSN 0022-2895, Vol. 39, no 3, 194-202 p.Article in journal (Refereed) Published
Abstract [en]

The authors investigated whether the discrepancy noted in the literature regarding delayed and decreased activity in vastus medialis obliquus (VMO) in people with patellofemoral pain (PFP) depends on the nature of the open kinetic chain (OKC) and the closed kinetic chain (CKC) in the experimental task. They hypothesized that activity in VMO would be more delayed and decreased in CKC tasks than in OKC tasks. Women with PFP (n = 17) and healthy controls (n = 17) performed isometric quadriceps contractions in CKC and OKC tasks. The authors manipulated only the application of resistance. Electromyographs (EMGs) showed that participants with PFP reacted later and activated the quadriceps more in the CKC task but had intramuscular quadriceps coordination similar to that of controls. The nature of the OKC task or the CKC task does not seem to explain contradictory findings regarding VMO activation.

Place, publisher, year, edition, pages
2007. Vol. 39, no 3, 194-202 p.
Keyword [en]
EMG, motor control, quadriceps, relative timing
Research subject
URN: urn:nbn:se:umu:diva-14596DOI: 10.3200/JMBR.39.3.194-202PubMedID: 17550871OAI: diva2:154268
Available from: 2008-01-09 Created: 2008-01-09 Last updated: 2015-11-30Bibliographically approved
In thesis
1. Motor control of the knee: kinematic and EMG studies of healthy individuals and people with patellofemoral pain
Open this publication in new window or tab >>Motor control of the knee: kinematic and EMG studies of healthy individuals and people with patellofemoral pain
2005 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Patellofemoral pain (PFP) is believed to be associated with deficits in coordination between the different heads of the quadriceps muscle; however, considerable debate exists in the literature regarding the presence of such a deficit. Discrepancies between studies may be explained by differences in experimental tasks, such as whether the task is performed with open (OKC) or closed kinetic chain (CKC), or whether the activity is voluntary or triggered. Particular interest has been directed toward the function of the vastus medialis obliquus (VMO), which is a short muscle with limited ability to exert torque across the knee joint, but probably has a particular role in controlling patellofemoral joint position. Another short muscle that may influence knee joint position control is popliteus (POP), which is located in the back of the knee.

This thesis investigates task specific activity of quadriceps in CKC versus OKC and studies the relative activity between the four heads of the quadriceps in PFP subjects compared to controls without knee pain in voluntary activity (CKC and OKC) and postural responses to balance perturbations. In addition, this thesis investigates the presumed function of POP for control of joint position in postural tasks in healthy individuals.

All subjects were of normal weight and height and between 18 and 40 years. Quadriceps activity was tested for isometric with identical joint configuration in CKC and OKC, and it was performed as a reaction time task. Balance perturbations were elicited by unpredictable anterior and posterior translations of the support surface. Function of POP was investigated in unpredictable support surface translations and in self induced provocations to balance by moving the arms. Muscle activity was recorded with electromyography (EMG). Optic kinematic analysis was used to obtain specific movement responses to perturbations of balance.

The quadriceps muscles were activated differently in CKC and OKC. VMO was activated earlier and to a greater degree in CKC. Rectus femoris was activated earlier and to a greater degree in OKC. PFP subjects reacted slower in both CKC and OKC, but there was no difference between groups in the relative activity between the different heads of the quadriceps. In the unpredictable support surface translation in the anterior direction, PFP subjects responded with earlier onset of VMO and with greater trunk and hip flexion in the anterior translation. POP activation in response to support surface translations in both directions occurred before all other muscles measured. In the self-initiated provocations of balance, POP was activated after the initiation of the balance provocation.

This thesis concludes that quadriceps activity was task specific. The lack of difference between groups in OKC and CKC, and the difference between groups in postural responses suggest that variations in motor behaviour may occur only in tasks habitually performed. Differences in muscle activation patterns may be related to compensatory strategies to unload the quadriceps muscles and the patellofemoral joint. Furthermore, this thesis suggests that POP muscle may have a particular role in active control of the knee joint.

Place, publisher, year, edition, pages
Umeå: Samhällsmedicin och rehabilitering, 2005. 90 p.
Umeå University medical dissertations, ISSN 0346-6612 ; 987
Kinematics; Kinetic chain tasks; Knee; Motor Control; Muscle activity; Patellofemoral pain; Unpredictable perturbations
National Category
urn:nbn:se:umu:diva-644 (URN)91-7305-951-X (ISBN)
Public defence
2005-12-16, Aulan, Vårdvetarhuset, Umeå Universitet, Umeå, 09:00 (English)
Available from: 2005-11-22 Created: 2005-11-22 Last updated: 2015-01-21Bibliographically approved

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