Effects of transcutaneous electrical nerve stimulation on quadriceps function in individuals with experimental knee pain

Abstract

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.

Prolonged Reduction in Shoulder Strength after Transcutaneous Electrical Nerve Stimulation Treatment of Exercise‐Induced Acute Muscle Pain

“…For the control group, our findings are also consistent with previous literature indicating that the negative effects of exercise‐induced injury are short term . However, our results do not support the theory that TENS restores function via analgesic mechanisms and diverge from previous studies suggesting excitatory effects of TENS on motor output …”

“…32,33 However, our results do not support the theory that TENS restores function via analgesic mechanisms 3 and diverge from previous studies suggesting excitatory effects of TENS on motor output. 22,73 We propose that a sensorimotor interaction following an acute episode of pain may have caused the prolonged inhibition of strength for the TENS treatment group. This is based on prior research suggesting that gross stimulation of afferent inputs may lead to changes at cortical sites and subsequently modulate motor output.…”

Decreased grip strength, muscle pain, and atrophy occur in rats following long‐term exposure to excessive repetitive motion

“…It is further worth noting that generally, pain reduces muscle strength . However, studies showed strong correlations between muscle force and either muscle volume or cross‐sectional area (CSA) .…”

Comparison of transcutaneous electrical nerve stimulation and lidocaine on episiotomy complication in primiparous women: A randomized clinical trial

“…[22] Therefore, several studies have recommended TENS to be a safe and viable nonpharmacological analgesic resource for episiotomy pain relief[2223] as well as other pains. [242526]…”