Brian Pietrosimone1, Adam S Lepley2, Amanda M Murray2, Abbey C Thomas2, Nael O Bahhur3, Todd A Schwartz4. 1. Department of Exercise and Sport Science, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States. Electronic address: brian@unc.edu. 2. Department of Kinesiology, University of Toledo, Toledo, OH, United States. 3. Department of Family Medicine, University of Toledo, Toledo, OH, United States. 4. Department of Biostatistics, Gillings School of Global Public Health, University of North Carolina at Chapel Hill, Chapel Hill, NC, United States.
Abstract
BACKGROUND: It has been hypothesized that arthrogenic muscle inhibition is responsible for altering physical function following knee injury. The association between the onset of arthrogenic muscle inhibition, measured using voluntary quadriceps activation, and changes in muscle strength and gait biomechanics are unknown. METHODS: Outcomes were collected before and following a 60 ml experimental knee effusion in eighteen healthy participants. Voluntary quadriceps activation was the predictor variable, while the criterion variable included, maximal voluntary isometric strength, peak knee flexion angle, peak internal knee extension moment, and peak vertical ground reaction forces during the first half of stance phase upon stair descent. Percent change scores (Δ) were imputed into linear regression equations to determine associations between predictor and criterion variables. FINDINGS: The variance in Δ voluntary quadriceps activation significantly predicted 87% the variance in the Δ strength (R(2)=0.87, P<0.001; Δ strength=-2.15+1.77Δ voluntary quadriceps activation) and 25% of the Δ vertical ground reaction force following effusion (R(2)=0.25, P=0.04; Δ vertical ground reaction force=-6.1+0.57 Δ voluntary quadriceps activation). After accounting for Δ knee flexion angle, Δ voluntary quadriceps activation predicted an additional 29% (Δ R(2)=0.29, P=0.007) of the variance in the Δ knee extension moment (R(2)=0.54, P=0.003, Δ knee extension moment=-10.79+0.74Δ knee flexion angle+1.64Δ voluntary quadriceps activation) following knee effusion. INTERPRETATION: Immediate quadriceps activation deficits following joint effusion result in immediate alterations in muscle strength, knee extensor moment and vertical ground reaction force during gait. Published by Elsevier Ltd.
BACKGROUND: It has been hypothesized that arthrogenic muscle inhibition is responsible for altering physical function following knee injury. The association between the onset of arthrogenic muscle inhibition, measured using voluntary quadriceps activation, and changes in muscle strength and gait biomechanics are unknown. METHODS: Outcomes were collected before and following a 60 ml experimental knee effusion in eighteen healthy participants. Voluntary quadriceps activation was the predictor variable, while the criterion variable included, maximal voluntary isometric strength, peak knee flexion angle, peak internal knee extension moment, and peak vertical ground reaction forces during the first half of stance phase upon stair descent. Percent change scores (Δ) were imputed into linear regression equations to determine associations between predictor and criterion variables. FINDINGS: The variance in Δ voluntary quadriceps activation significantly predicted 87% the variance in the Δ strength (R(2)=0.87, P<0.001; Δ strength=-2.15+1.77Δ voluntary quadriceps activation) and 25% of the Δ vertical ground reaction force following effusion (R(2)=0.25, P=0.04; Δ vertical ground reaction force=-6.1+0.57 Δ voluntary quadriceps activation). After accounting for Δ knee flexion angle, Δ voluntary quadriceps activation predicted an additional 29% (Δ R(2)=0.29, P=0.007) of the variance in the Δ knee extension moment (R(2)=0.54, P=0.003, Δ knee extension moment=-10.79+0.74Δ knee flexion angle+1.64Δ voluntary quadriceps activation) following knee effusion. INTERPRETATION: Immediate quadriceps activation deficits following joint effusion result in immediate alterations in muscle strength, knee extensor moment and vertical ground reaction force during gait. Published by Elsevier Ltd.
Authors: Brittney A Luc-Harkey; Matthew S Harkey; Derek N Pamukoff; Rebecca H Kim; Troy K Royal; J Troy Blackburn; Jeffery T Spang; Brian Pietrosimone Journal: Exp Brain Res Date: 2017-01-31 Impact factor: 1.972
Authors: Sarah H Ward; J Troy Blackburn; Darin A Padua; Laura E Stanley; Matthew S Harkey; Brittney A Luc-Harkey; Brian Pietrosimone Journal: J Athl Train Date: 2018-01-19 Impact factor: 2.860
Authors: A Evans-Pickett; L Longobardi; J T Spang; R A Creighton; G Kamath; H C Davis-Wilson; R Loeser; J T Blackburn; B Pietrosimone Journal: Osteoarthritis Cartilage Date: 2021-03-27 Impact factor: 7.507