Reliability of surface electromyographic recordings during walking in individuals with knee osteoarthritis.
To determine test-retest reliability of a surface electromyographic protocol designed to measure knee joint muscle activation during walking in individuals with knee osteoarthritis (OA). Twenty-one individuals with moderate medial compartment knee OA completed two gait data collections separated by approximately 1month. Using a standardized protocol, surface electromyograms from rectus femoris plus lateral and medial sites for the gastrocnemii, vastii and hamstring muscles were recorded during walking. After full-wave rectification and low pass filtering, time and amplitude normalized (percent of maximum) waveforms were calculated. Principal component analysis (PP-scores) and co-contraction indices (CCI) were calculated from the waveforms. Intraclass correlation coefficients (ICC2,k) were calculated for PP-scores and CCI's. No differences in walking speed, knee muscle strength and symptoms were found between visits (p>0.05). The majority of PP-scores (17 of 21) and two of four CCIs demonstrated ICC2,k values greater than 0.81. Remaining PP-scores and CCIs had ICC2,k values between 0.61 and 0.80. The results support that reliable EMG characteristics can be captured from a moderate knee OA patient population using a standardized protocol.
School of Physiotherapy, Dalhousie University, Halifax, NS, Canada. cheryl.kozey@dal.ca
Cheryl L
CL
Hubley-Kozey
Shawn M
SM
Robbins
Derek J
DJ
Rutherford
William D
WD
Stanish
D000200:Action Potentials; D004576:Electromyography / Q000379:methods*; D005260:Female; D005684:Gait; D020233:Gait Disorders, Neurologic / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000503:physiopathology*; D020370:Osteoarthritis, Knee / Q000150:complications / Q000503:physiopathology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D016138:Walking