Quadriceps Surface Research Articles

Acute Neuromuscular Response to Team Sports-Specific Running, Resistance, and Concurrent Training: A Crossover Study.

This study aimed to examine the changes in muscle contractile function, voluntary activation, and muscle damage after lower limb resistance training (RT), intermittent sprint exercise, and concurrent training (CT). Ten male, recreational team sport athletes with a history of RT participated in a randomized crossover study involving an intermittent sprint protocol (ISP), lower limb RT, and CT (ISP and RT separated by 1 h). Before (PRE), immediately after (POST), 24 h and 48 h after each exercise condition, quadriceps muscle activation, voluntary activation, muscle contractile function (evoked twitch responses), creatine kinase, muscle soreness, and Profile of Mood States (POMS)-fatigue were recorded. Quadriceps contractile function was hampered in all conditions, with a significantly greater decline observed POST RT (58.4% ± 18.0%) and CT (54.8% ± 8.6%) compared with ISP (35.9% ± 10.7%, P < 0.05), recovering at 48 h after all exercise conditions. POMS-fatigue ratings increased at POST in all conditions with CT and ISP eliciting the greatest increase, returning to baseline 48 h after all exercise conditions. Quadriceps muscle soreness remained elevated from PRE at 48 h after all exercise conditions. No changes across time were observed for voluntary activation and quadriceps surface EMG amplitude after any exercise condition. The volume and load lifted in the RT session was unaffected by previous intermittent exercise (ISP) in CT. RT impairs contractile function, which is not exacerbated when performed 1 h after the ISP. Contractile function after all exercise conditions displayed the same recovery profile (48 h) despite the postexercise decrement being smaller after the ISP compared with RT and CT. Previous intermittent sprint exercise does not negatively affect the volume of exercise performed in a lower limb RT session.

Explosive strength: effect of knee-joint angle on functional, neural, and intrinsic\xa0contractile properties

PurposeThe present study compared knee extension explosive isometric torque, neuromuscular activation, and intrinsic contractile properties at five different knee-joint angles (35°, 50°, 65°, 80°, and 95°; 0° = full knee extension).MethodsTwenty-eight young healthy males performed two experimental sessions each involving: 2 maximum, and 6–8 explosive voluntary contractions at each angle; to measure maximum voluntary torque (MVT), explosive voluntary torque (EVT; 50–150 ms after contraction onset) and quadriceps surface EMG (QEMG, 0–50, 0–100, and 0–150 ms after EMG onset during the explosive contractions). Maximum twitch and M-wave (MMAX) responses as well as octet contractions were evoked with femoral nerve stimulation at each angle.ResultsAbsolute MVT and EVT showed an inverted ‘U’ relationship with higher torque at intermediate angles. There were no differences between knee-joint angles for relative EVT (%MVT) during the early phase (≤ 75 ms) of contraction and only subtle differences during the late phase (≥ 75 ms) of contraction (≤ 11%). Neuromuscular activation during explosive contractions was greater at more flexed than extended positions, and this was also the case during MVT. Whilst relative twitch torque (%MVT) was higher at knee flexed positions (P ≤ 0.001), relative octet torque (%MVT) was higher at knee extended positions (P ≤ 0.001).ConclusionRelative EVT was broadly similar between joint angles, likely because neuromuscular activation during both explosive and plateau (maximum) phases of contraction changed proportionally, and due to the opposing changes in twitch and octet evoked responses with joint angle.

Adductor Canal Nerve Versus Femoral Nerve Blockade for Pain Control and Quadriceps Function Following Anterior Cruciate Ligament Reconstruction With Patellar Tendon Autograft: A Prospective Randomized Trial

To compare femoral nerve blockade (FNB) versus adductor canal nerve blockade (ACB) for postoperative pain control and quadriceps muscle function in patients undergoing anterior cruciate ligament (ACL) reconstruction with patellar tendon autograft. A randomized therapeutic trial of 90 patients undergoing ACL reconstruction with patellar tendon autograft was conducted comparing ACB versus FNB at 24hours, 2 and 4 weeks, and 6months postsurgery. Early outcome measures included average pain score and morphine equivalent units (milligrams) consumed, quadriceps surface electromyography, straight leg raise, and ability to ambulate without assistive devices. The 6-month outcome measures included knee range of motion (ROM), isokinetic knee extension peak torque, single-leg squat, and single-leg hop performance. Complications were recorded throughout the study for the development of anterior knee pain, knee extension ROM loss, deep vein thrombosis, and graft failure. Mixed-model analysis of variance and Mann-Whitney U tests were performed using an alpha of .05. Quadriceps surface electromyography deficits were higher for FNB at 24hours (P < .001) and 2weeks (P < .001) when compared with the ACB group. There were no between-groups difference for subjective pain (P= .793) or morphine consumption (P= .358) within the first 24hours of surgery. A higher percentage of patients in the ACB group met the full ambulation criteria at 4weeks compared with the FNB group (100% vs 84.2%, P < .001). No between-group differences were observed at 6months; however, the rate of knee extension ROM loss was higher for the FNB group versus the ACB group (21.1% vs 5.0%, P= .026), respectively. ACB was as effective as FNB at providing pain control while eliciting fewer quadriceps muscle activation deficits and fewer postoperative complications. Based on previous evidence and the results of this study, we recommend the use of ACB over FNB for theanalgesic management of patients undergoing ACL reconstruction with patellar tendon autograft. Level I, prospective randomized controlled trial.

Reliability of quadriceps surface electromyography measurements is improved by two vs. single site recordings

PurposeThe reliability of surface electromyography (sEMG) is typically modest even with rigorous methods, and therefore further improvements in sEMG reliability are desirable. This study compared the between-session reliability (both within participant absolute reliability and between-participant relative reliability) of sEMG amplitude from single vs. average of two distinct recording sites, for individual muscle (IM) and whole quadriceps (WQ) measures during voluntary and evoked contractions.MethodsHealthy males (n = 20) performed unilateral isometric knee extension contractions: voluntary maximum and submaximum (60%), as well as evoked twitch contractions on two separate days. sEMG was recorded from two distinct sites on each superficial quadriceps muscle.ResultsAveraging two recording sites vs. using single site measures improved reliability for IM and WQ measurements during voluntary (16–26% reduction in within-participant coefficient of variation, CVW) and evoked contractions (40–56% reduction in CVW).ConclusionsFor sEMG measurements from large muscles, averaging the recording of two distinct sites is recommended as it improves within-participant reliability. This improved sensitivity has application to clinical and research measurement of sEMG amplitude.

Lumbar Radiculopathy Confounded: Total Knee Arthroplasty Diminishes the Patellar Tendon Reflex.

Patellar tendon reflexes were elicited among patients who had had a unilateral total knee replacement, those planned for unilateral total knee replacement, and a cohort of controlled patients. Patellar tendon reflex (PTR) response was measured with surface electromyography. The aim of this study was to determine if total knee arthroplasty significantly alters the PTR. As part of the clinical evaluation of the spine, extremity reflexes are provoked. Reflex variation between right and left extremities can be a pathological finding in disease of the spine. It has been noted that in patients who have undergone total knee arthroplasty (TKA), the PTR is diminished on the operative side compared with the contralateral nonoperative side. PTR is part of the clinical exam when evaluating a patient for lumbar radiculopathy. The right and left patellar tendon reflex intensities were measured by quadriceps surface electromyography in 3 groups of patients. Group 1 consisted of 21 patients with unilateral TKA who were at least 6 months postoperative. Group 2 consisted of 18 patients with unilateral severe knee arthritis indicated for TKA. Group 3, serving as the control group, included 20 patients with no evidence of knee arthritis in either knee. The average reflex response for each group was recorded and comparisons were then made between each group. Patients who have undergone unilateral TKA have a PTR on average of 55.1% of their contralateral uninvolved side. This is statistically significant when compared with reflexes in patients who are planned for unilateral total knee arthroplasty, 96.03% (P = 0.001) and when compared with patients without evidence for knee arthritis, 102.2% (P < 0.001). The results of this case control study show that TKAs do significantly diminish PTRs when compared with a contralateral uninvolved knee in the same patient. 3.

Longitudinal Decline of Neuromuscular Activation and Power in Healthy Older Adults

Weakness contributes to the decline of physical function that occurs with aging. Contradictory findings have been reported as to whether neuromuscular activation is impaired with aging, and the extent to which it contributes to weakness. The present study uses a longitudinal design to assess how potential age-related change of neuromuscular activation affects strength, power, and mobility function. Participants included 16 healthy older adults who were healthy and high functioning at baseline. Strength was measured by leg press one repetition maximum. Power production was measured during a maximal effort rapid leg press movement with resistance set to 70% of the one repetition maximum. During the same movement, neuromuscular activation was quantified as the rate of rise of the quadriceps surface electromyogram (rate of electromyogram rise). Thigh muscle cross-sectional area was measured by computed tomography. Mobility function was assessed by the Short Physical Performance Battery. The time between baseline and follow-up testing was almost 3 years. Between these time points, rate of electromyogram rise decreased 28% (p = .004) and power decreased 16.5% (p = .01). There was a trend for reduced anterior thigh muscle cross-sectional area (3%, p = .05), but no change in posterior thigh muscle cross-sectional area (p = .84), one repetition maximum strength (p = .72), or Short Physical Performance Battery score (p = .17). Loss of power was strongly associated with reduction in the rate of electromyogram rise (R (2) = .61, p < .001), but not with reduction of anterior thigh muscle cross-sectional area (p = .83). The present findings suggest that voluntary neuromuscular activation declines with advancing age, contributes to a reduction in power production, and precedes the decline of mobility function.

Effects of early application of Tuina treatment on quadriceps surface myoelectricity in patients after total knee arthroplasty: a randomized controlled trial

Total knee replacement surgery is commonly used in end-stage diseases of the knee. It is important for improving surgical efficacy and patient satisfaction by promoting early rehabilitation of patients and improving knee function. To observe the effects of early application of Tuina treatment on quadriceps surface electromyography (EMG) in patients with rheumatoid arthritis having undergone total knee arthroplasty. The study was performed at the Orthopedic Department of Huashan Hospital, Fudan University, and the Shanghai Guanghua Hospital of Integrated Traditional Chinese and Western Medicine from June 2010 to September 2011. A total of 66 patients with rheumatoid arthritis who had undergone total knee replacement surgery were randomly divided into control group and observation group, 33 cases in each. The patients in the control group were administered with continuous passive training (CPM), and the patients in the observation group were treated with CPM combined with Tuina, from prior surgery to four weeks post-surgery. The knee function was evaluated using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire at baseline and 4 weeks after the surgery. Quadriceps surface EMG was also detected at the same time points. After 4 weeks of Tuina and comprehensive rehabilitation intervention, the WOMAC questionnaire score of the observation group was decreased compared with the control group (P<0.01); median frequency and integrated electromyography of the rectus femoris and vastus medialis muscles, which were recorded by EMG, in the observation group were higher than those in the control group (P<0.01). Tuina can improve the recovery of patients who have undergone total knee replacement by increasing quadriceps EMG.