Effects of transcutaneous electrical nerve stimulation on quadriceps function in individuals with experimental knee pain.
Knee joint pain (KJP) is a cardinal symptom in knee pathologies, and quadriceps inhibition is commonly observed among KJP patients. Previously, KJP independently reduced quadriceps strength and activation. However, it remains unknown how disinhibitory transcutaneous electrical nerve stimulation (TENS) will affect inhibited quadriceps motor function. This study aimed at examining changes in quadriceps maximum voluntary contraction (MVC) and central activation ratio (CAR) before and after sensory TENS following experimental knee pain. Thirty healthy participants were assigned to either the TENS or placebo groups. All participants underwent three separate data collection sessions consisting of two saline infusions and one no infusion control in a crossover design. TENS or placebo treatment was administered to each group for 20 min. Quadriceps MVC and CAR were measured at baseline, infusion, treatment, and post-treatment. Perceived knee pain intensity was measured on a 100-mm visual analogue scale. Post-hoc analysis revealed that hypertonic saline infusion significantly reduced the quadriceps MVC and CAR compared with control sessions (P < 0.05). Sensory TENS, however, significantly restored inhibited quadriceps motor function compared with placebo treatment (P < 0.05). There was a negative correlation between changes in MVC and knee pain (r = 0.33, P < 0.001), and CAR and knee pain (r = 0.62, P < 0.001), respectively.
Department of Exercise Sciences, Human Performance Research Center, Brigham Young University, Provo, Utah, USA.
S J
SJ
Son
Department of Kinesiology, West Chester University, West Chester, Pennsylvania, USA.
H
H
Kim
Department of Exercise Sciences, Human Performance Research Center, Brigham Young University, Provo, Utah, USA.
M K
MK
Seeley
Department of Exercise Sciences, Human Performance Research Center, Brigham Young University, Provo, Utah, USA.
J B
JB
Feland
Department of Exercise Sciences, Human Performance Research Center, Brigham Young University, Provo, Utah, USA.
J T
JT
Hopkins
D000328:Adult; D018771:Arthralgia / Q000139:chemically induced / Q000503:physiopathology* / Q000628:therapy*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D010147:Pain Measurement; D052097:Quadriceps Muscle / Q000503:physiopathology*; D012462:Saline Solution, Hypertonic; D019415:Torque; D004561:Transcutaneous Electric Nerve Stimulation; D055815:Young Adult
D012462:Saline Solution, Hypertonic
Pain receptor; arthrogenic muscle inhibition; articular cartilage; disinhibitory modality; electrotherapy; motor neuron; osteoarthritis; sterile hypertonic saline