Knee Extension Lag: Difference between revisions
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functional relevance for patients during knee rehabilitation. <br> | functional relevance for patients during knee rehabilitation. <br> | ||
== Technique<br> == | == Technique<ref>Sebastian D, Chovvath R, Malladi R. The sitting active and prone passive lag test: an inter-rater reliability study.J Bodyw Mov Ther. 2014 Apr;18(2):204-9.</ref><br> == | ||
Muscle lag is an inability to actively move a joint to its passive limit. In more detail, the passive limit should be the passive limit that can be achieved without producing significant discomfort, and without exerting more than mild force against resistance from joint stiffness or other soft tissue tightness. The active limit should be determined with the patient positioned so that the moving segment is resisted by gravity but no other external load. | |||
=== Active Lag Test === | |||
An active lag was determined by the inability of the erectly seated subject to actively extend the involved knee in maximal dorsiflexion of the ankle to the same level as the normal knee held in maximal extension and ankle in maximal dorsiflexion, as seen by the levels of the toes. | An active lag was determined by the inability of the erectly seated subject to actively extend the involved knee in maximal dorsiflexion of the ankle to the same level as the normal knee held in maximal extension and ankle in maximal dorsiflexion, as seen by the levels of the toes. | ||
A passive lag was determined by placing the subject prone with the knees just past the edge of the table and determining the high position of the heel in a fully resting extension position compared to the heel on the normal side. | |||
=== Passive Lag Test === | |||
A passive lag was determined by placing the subject prone with the knees just past the edge of the table and determining the high position of the heel in a fully resting extension position compared to the heel on the normal side. | |||
It appears there is a widespread belief that lag is always abnormal.<br> | |||
=== Physiological quadriceps lag === | |||
A study done on physiological quadriceps lag has shown that most healthy young adults, when assessed in the manner described, manifest a quadriceps lag. At the instant of maximum voluntary active extension, 48% of the 64 subjects had a quadriceps lag of between 2.0 and 10.5 degrees. Since these subjects had no pain, and further passive extension was possible without substantial passive resistance, this lag at 0 sec can only be readily explained as a manifestation of normal quadriceps femoris active insufficiency, perhaps augmented in some subjects by a less than maximum voluntary effort. The apparent absence of any reference in the literature to quadriceps lag in normal knees is most likely because quadriceps lag does not appear to have been examined systematically in healthy subjects. | |||
== Evidence == | == Evidence == | ||
Revision as of 06:38, 10 June 2014
Original Editor - Ajay Upadhyay
Top Contributors - Laura Ritchie, Kim Jackson, Ajay Upadhyay, Nehal Shah, Admin, Evan Thomas, WikiSysop, Wanda van Niekerk and Lauren Lopez
Purpose
[edit | edit source]
The term ‘muscle lag’ or ‘extensor lag’ or ‘quadriceps lag’ is a clinical sign with often profound
functional relevance for patients during knee rehabilitation.
Technique[1]
[edit | edit source]
Muscle lag is an inability to actively move a joint to its passive limit. In more detail, the passive limit should be the passive limit that can be achieved without producing significant discomfort, and without exerting more than mild force against resistance from joint stiffness or other soft tissue tightness. The active limit should be determined with the patient positioned so that the moving segment is resisted by gravity but no other external load.
Active Lag Test[edit | edit source]
An active lag was determined by the inability of the erectly seated subject to actively extend the involved knee in maximal dorsiflexion of the ankle to the same level as the normal knee held in maximal extension and ankle in maximal dorsiflexion, as seen by the levels of the toes.
Passive Lag Test[edit | edit source]
A passive lag was determined by placing the subject prone with the knees just past the edge of the table and determining the high position of the heel in a fully resting extension position compared to the heel on the normal side.
It appears there is a widespread belief that lag is always abnormal.
Physiological quadriceps lag[edit | edit source]
A study done on physiological quadriceps lag has shown that most healthy young adults, when assessed in the manner described, manifest a quadriceps lag. At the instant of maximum voluntary active extension, 48% of the 64 subjects had a quadriceps lag of between 2.0 and 10.5 degrees. Since these subjects had no pain, and further passive extension was possible without substantial passive resistance, this lag at 0 sec can only be readily explained as a manifestation of normal quadriceps femoris active insufficiency, perhaps augmented in some subjects by a less than maximum voluntary effort. The apparent absence of any reference in the literature to quadriceps lag in normal knees is most likely because quadriceps lag does not appear to have been examined systematically in healthy subjects.
Evidence[edit | edit source]
For the sitting active lag test, the inter-rater reliability was 'good' (Kappa 0.792, SE of kappa 0.115, 95% confidence interval). For the prone passive lag test, the inter-rater reliability was 'good' (Kappa 0.636, SE of kappa 0.136, 95% confidence interval).
Resources[edit | edit source]
Sebastian D, Chovvath R, Malladi R. The sitting active and prone passive lag test: an inter-rater reliability study.J Bodyw Mov Ther. 2014 Apr;18(2):204-9.
Recent Related Research (from Pubmed)[edit | edit source]
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References[edit | edit source]
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- ↑ Sebastian D, Chovvath R, Malladi R. The sitting active and prone passive lag test: an inter-rater reliability study.J Bodyw Mov Ther. 2014 Apr;18(2):204-9.
