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Quadriceps activation following knee injuries: a systematic review

PainSci » bibliography » Hart et al 2010
Tags: patellar pain, knee, arthritis, etiology, aging, pain problems, leg, limbs, overuse injury, injury, running, exercise, self-treatment, treatment, pro

Two articles on PainSci cite Hart 2010: 1. The Complete Guide to Patellofemoral Pain Syndrome2. What Can a Runner With Knee Pain Do at the Gym?

PainSci notes on Hart 2010:

This study reviewed the existing research on "arthrogenic muscle inhibition" — defined as an inability to fully activate your muscle voluntarily due to joint problems as opposed to muscle or nerve problems. Specifically, it investigated AMI as a factor in persistent quadriceps weakness after knee injury or surgery.

The results of this study indicate that many different knee issues indeed cause a 10 to 20% decrease in voluntary quadriceps activation. This includes people who have had ACL ruptures (which remains even after surgical repair), osteoarthritis, and anterior knee pain syndromes.

Interestingly, it also seems that this quadriceps inhibition exists in both legs — even for one sided injury or pain!

original abstract Abstracts here may not perfectly match originals, for a variety of technical and practical reasons. Some abstacts are truncated for my purposes here, if they are particularly long-winded and unhelpful. I occasionally add clarifying notes. And I make some minor corrections.

CONTEXT: Arthrogenic muscle inhibition is an important underlying factor in persistent quadriceps muscle weakness after knee injury or surgery.

OBJECTIVE: To determine the magnitude and prevalence of volitional quadriceps activation deficits after knee injury.

DATA SOURCES: Web of Science database.

STUDY SELECTION: Eligible studies involved human participants and measured quadriceps activation using either twitch interpolation or burst superimposition on patients with knee injuries or surgeries such as anterior cruciate ligament deficiency (ACLd), anterior cruciate ligament reconstruction (ACLr), and anterior knee pain (AKP).

DATA EXTRACTION: Means, measures of variability, and prevalence of quadriceps activation (QA) failure (<95%) were recorded for experiments involving ACLd (10), ACLr (5), and AKP (3).

DATA SYNTHESIS: A total of 21 data sets from 18 studies were initially identified. Data from 3 studies (1 paper reporting data for both ACLd and ACLr, 1 on AKP, and the postarthroscopy paper) were excluded from the primary analyses because only graphical data were reported. Of the remaining 17 data sets (from 15 studies), weighted mean QA in 352 ACLd patients was 87.3% on the involved side, 89.1% on the uninvolved side, and 91% in control participants. The QA failure prevalence ranged from 0% to 100%. Weighted mean QA in 99 total ACLr patients was 89.2% on the involved side, 84% on the uninvolved side, and 98.5% for the control group, with prevalence ranging from 0% to 71%. Thirty-eight patients with AKP averaged 78.6% on the involved side and 77.7% on the contralateral side. Bilateral QA failure was commonly reported in patients.

CONCLUSIONS: Quadriceps activation failure is common in patients with ACLd, ACLr, and AKP and is often observed bilaterally.

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