Central Activation Ratio Is a Reliable Measure for Gluteal Neuromuscular Function

2020 ◽  
Vol 29 (7) ◽  
pp. 956-962
Author(s):  
Daniel Gilfeather ◽  
Grant Norte ◽  
Christopher D. Ingersoll ◽  
Neal R. Glaviano
Keyword(s):  
Isometric Contraction ◽  
Outcome Measure ◽  
Intraclass Correlation ◽  
Neuromuscular Function ◽  
Healthy Population ◽  
Maximal Voluntary Isometric Contraction ◽  
Central Activation ◽  
Central Activation Ratio ◽  
Hip Abduction ◽  
Activation Ratio

Context: Central activation ratio (CAR) is a common outcome measure used to quantify gross neuromuscular function of the quadriceps using the superimposed burst technique, yet this outcome measure has not been validated in the gluteal musculature. Objective: To quantify gluteus medius (GMed) and gluteus maximus (GMax) CAR in a healthy population and evaluate its validity and reliability over a 1-week period. Design: Descriptive. Setting: Laboratory. Patients or Other Participants: A total of 20 healthy participants (9 males and 11 females; age 22.2 [1.4] y, height 173.4 [11.1] cm, mass 84.8 [25.8] kg) were enrolled in this study. Interventions: Participants were assessed at 2 sessions, separated by 1 week. Progressive electrical stimuli (25%, 50%, 75%, and 100%) were delivered to the GMed and GMax at rest, and 100% stimuli were delivered during progressive hip abduction and extension contractions (25%, 50%, 75%, and 100% maximal voluntary isometric contraction). Main Outcome Measures: GMed and GMax CAR, and hip abduction and hip extension maximal voluntary isometric contraction torque. Line of best fit and coefficient of determination (r2) were used to assess the relationship between torque output and CAR at varying levels of stimuli. Intraclass correlation coefficients, ICCs(3,k), were used to assess the between-session reliability. Results: GMed CAR was 96.1% (3.4%) and 96.6% (3.2%), on visits 1 and 2, respectively, whereas GMax CAR was 86.5% (7.5%) and 87.2% (10.7%) over the 2 sessions. A third-order polynomial demonstrated the best line of fit between varying superimposed burst intensities at rest for both GMed (r2 = .156) and GMax (r2 = .602). Linear relationships were observed in the CAR during progressive contractions with a maximal superimposed burst, GMed (r2 = .409) and GMax (r2 = .639). Between-session reliability was excellent for GMed CAR, ICC(3,k) = .911, and moderate for GMax CAR, ICC(3,k) = .704. Conclusion: CAR appears to be an acceptable measure of GMed and GMax neuromuscular function in healthy individuals. Gluteal CAR measurements are reliable measures over a 1-week test period.

scholarly journals Reliability of the Superimposed-Burst Technique in Patients With Patellofemoral Pain: A Technical Report

2015 ◽  
Vol 50 (11) ◽  
pp. 1207-1211 ◽  
Author(s):  
Grant E. Norte ◽  
Jamie L. Frye ◽  
Joseph M. Hart
Keyword(s):  
Intraclass Correlation ◽  
Correlation Coefficients ◽  
Knee Extension ◽  
Patellofemoral Pain ◽  
Maximal Voluntary Isometric Contraction ◽  
Joint Injury ◽  
Central Activation ◽  
Central Activation Ratio ◽  
Healthy Control ◽  
Activation Ratio

Context  The superimposed-burst (SIB) technique is commonly used to quantify central activation failure after knee-joint injury, but its reliability has not been established in pathologic cohorts. Objective  To assess within-session and between-sessions reliability of the SIB technique in patients with patellofemoral pain. Design  Descriptive laboratory study. Setting  University laboratory. Patients or Other Participants  A total of 10 patients with self-reported patellofemoral pain (1 man, 9 women; age = 24.1 ± 3.8 years, height = 167.8 ± 15.2 cm, mass = 71.6 ± 17.5 kg) and 10 healthy control participants (3 men, 7 women; age = 27.4 ± 5.0 years, height = 173.5 ± 9.9 cm, mass = 78.2 ± 16.5 kg) volunteered. Intervention(s)  Participants were assessed at 6 intervals spanning 21 days. Intraclass correlation coefficients (ICCs [3,3]) were used to assess reliability. Main Outcome Measure(s)  Quadriceps central activation ratio, knee-extension maximal voluntary isometric contraction force, and SIB force. Results  The quadriceps central activation ratio was highly reliable within session (ICC [3,3] = 0.97) and between sessions through day 21 (ICC [3,3] = 0.90–0.95). Acceptable reliability of knee extension (ICC [3,3] = 0.75–0.91) and SIB force (ICC [3,3] = 0.77–0.89) was observed through day 21. Conclusions  The SIB technique was reliable for clinical research up to 21 days in patients with patellofemoral pain.

Quadriceps function in anterior cruciate ligament-deficient knees exercising with transcutaneous electrical nerve stimulation and cryotherapy: a randomized controlled study

2012 ◽  
Vol 26 (11) ◽  
pp. 974-981 ◽  
Author(s):  
Joseph M Hart ◽  
Christopher M Kuenze ◽  
Brian G Pietrosimone ◽  
Christopher D Ingersoll
Keyword(s):  
Anterior Cruciate Ligament ◽  
Cruciate Ligament ◽  
Knee Extension ◽  
Exercise Session ◽  
Central Activation ◽  
Central Activation Ratio ◽  
Extension Force ◽  
Activation Ratio ◽  
Anterior Cruciate ◽  
Anterior Cruciate Ligament Deficient

Objective: To compare strength and quadriceps muscle activation in anterior cruciate ligament-deficient patients who underwent a two-week rehabilitation exercise program using TENS or cryotherapy. Design: Randomized, controlled study. Setting: Clinical research laboratory. Subjects: Thirty patients: 20 males, 10 females, 31.6 (13.0) years, 172.8 (10.0) cm, 75.8 (13.0) kg with diagnosed tear of the anterior cruciate ligament. Interventions: All patients attended four sessions of supervised quadriceps strengthening exercises over two weeks, prior to reconstruction surgery. Patients were randomly allocated ( n = 10/group) to receive exercises alone, exercise while wearing a sensory transcutaneous electrical nerve stimulation (TENS) device on the knee joint for the duration of each daily session, or 20 minutes of knee joint cryotherapy immediately prior to each daily exercise session. Main measures: Normalized knee extension force and quadriceps central activation ratio were measured before and after the first supervised treatment session and within 24 hours of the last session. Results: When accounting for differences in baseline measures, there were no statistically significant group differences immediately following the first exercise session for knee extension force ( P = 0.10) or central activation ratio ( P = 0.30) nor were there statistically significant group differences after the two-week intervention for knee extension force ( P = 0.92) or central activation ratio ( P = 0.94). Effect sizes for the change in knee extension force and central activation ratio after two weeks of therapy were all large. Conclusions: Quadriceps strength and central activation in anterior cruciate ligament deficient patients improved after two weeks of rehabilitaiton exercises, however, there were no significant differences between treatment groups.

scholarly journals Effect of Hip Abduction Maximal Voluntary Isometric Contraction on Lumbar Motion and Power Output During the Back Squat

2018 ◽  
Vol 6 (1) ◽  
pp. 1
Author(s):  
Christopher F. Kelly ◽  
Adam M. Gonzalez ◽  
Robert W. Spitz ◽  
Katie M. Sell ◽  
Jamie J. Ghigiarelli
Keyword(s):  
Isometric Contraction ◽  
Power Output ◽  
Maximum Deviation ◽  
Lateral Flexion ◽  
Maximal Voluntary Isometric Contraction ◽  
Lumbar Flexion ◽  
Back Squat ◽  
Squat Exercise ◽  
Hip Abduction ◽  
Lumbar Motion

Background: Post-activation potentiation (PAP) is a neuromuscular phenomenon that has been shown to augment muscular force generating attributes as well as neural and sensory recruitment. While PAP has demonstrated to acutely enhance muscular performance during high-intensity activities, the effect of PAP on lumbopelvic kinematics under load remains unknown. Objectives: The purpose of this study was to examine the potential PAP effect of a hip abduction maximal voluntary isometric contraction (MVIC) on lumbar motion and power output during the barbell back squat.  Methods: Nine resistance-trained men (22.9±2.3 y; 85.0±13.8 kg; 174.3±5.1 cm) performed a set of 5 repetitions of the barbell back squat using 80% one-repetition maximum with and without a hip abduction MVIC prior to performance.  Experimental and control trials were randomized and counterbalanced among participants.  MVIC was carried out via manual long-lever hip abduction.  During the back squat exercise, lumbar motion analysis was performed using wireless motion-sensor technology, and power output was assessed via an accelerometer.  Results: No significant differences were observed between trials for lumbar flexion range of motion (ROM) (p=0.32), lumbar flexion maximum deviation (p=0.32), lumbar lateral flexion ROM (p=0.81), lumbar lateral flexion maximum deviation (p=0.98), lumbar rotation maximum deviation (p=0.70), average peak power (p=0.98), or average mean power output (p=0.99) during the squat protocol.  Conclusions: Implementation of a manual long-lever hip abduction MVIC prior to the back squat exercise did not significantly alter lumbar motion or augment power output in resistance trained males. 

scholarly journals Pain and Effusion and Quadriceps Activation and Strength

2013 ◽  
Vol 48 (2) ◽  
pp. 186-191 ◽  
Author(s):  
Riann M. Palmieri-Smith ◽  
Mark Villwock ◽  
Brian Downie ◽  
Garin Hecht ◽  
Ron Zernicke
Keyword(s):  
Knee Joint ◽  
Outcome Measure ◽  
Quadriceps Strength ◽  
Joint Effusion ◽  
Joint Injury ◽  
Central Activation Ratio ◽  
Normal Knee ◽  
Knee Joint Injury ◽  
Activation Ratio ◽  
Painful Knee

Context: Quadriceps dysfunction is a common consequence of knee joint injury and disease, yet its causes remain elusive. Objective: To determine the effects of pain on quadriceps strength and activation and to learn if simultaneous pain and knee joint effusion affect the magnitude of quadriceps dysfunction. Design: Crossover study. Setting: University research laboratory. Patients or Other Participants: Fourteen (8 men, 6 women; age = 23.6 ± 4.8 years, height = 170.3 ± 9.16 cm, mass = 72.9 ± 11.84 kg) healthy volunteers. Intervention(s): All participants were tested under 4 randomized conditions: normal knee, effused knee, painful knee, and effused and painful knee. Main Outcome Measure(s): Quadriceps strength (Nm/kg) and activation (central activation ratio) were assessed after each condition was induced. Results: Quadriceps strength and activation were highest under the normal knee condition and differed from the 3 experimental knee conditions (P < .05). No differences were noted among the 3 experimental knee conditions for either variable (P > .05). Conclusions: Both pain and effusion led to quadriceps dysfunction, but the interaction of the 2 stimuli did not increase the magnitude of the strength or activation deficits. Therefore, pain and effusion can be considered equally potent in eliciting quadriceps inhibition. Given that pain and effusion accompany numerous knee conditions, the prevalence of quadriceps dysfunction is likely high.

Focal knee joint cooling increases the quadriceps central activation ratio

2009 ◽  
Vol 27 (8) ◽  
pp. 873-879 ◽  
Author(s):  
Brian G. Pietrosimone ◽  
Christopher D. Ingersoll
Keyword(s):  
Knee Joint ◽  
Central Activation ◽  
Central Activation Ratio ◽  
Activation Ratio

Central activation deficits contribute to post stroke lingual weakness in a rat model

2021 ◽  
Author(s):  
Miranda J. Cullins ◽  
John A. Russell ◽  
Zoe E. Booth ◽  
Nadine P. Connor
Keyword(s):  
Muscle Fiber ◽  
Muscle Activation ◽  
Fiber Type ◽  
Muscle Fiber Type ◽  
Force Frequency ◽  
Muscle Twitch ◽  
Central Activation ◽  
Central Activation Ratio ◽  
Generating Capacity ◽  
Activation Ratio

Lingual weakness frequently occurs after stroke and is associated with deficits in speaking and swallowing. Chronic weakness after stroke has been attributed to both impaired central activation of target muscles and reduced force generating capacity within muscles. How these factors contribute to lingual weakness is not known. We hypothesized that lingual weakness due to middle cerebral artery occlusion (MCAO) would manifest as reduced muscle force capacity and reduced muscle activation. Rats were randomized into MCAO or sham surgery groups. Maximum volitional tongue forces were quantified 8 weeks after surgery. Hypoglossal nerve stimulation was used to assess maximum stimulated force, muscle twitch properties, and force-frequency response. The central activation ratio was determined by maximum volitional/maximum stimulated force. Genioglossus muscle fiber type properties and neuromuscular junction innervation were assessed. Maximum volitional force and the central activation ratio were significantly reduced with MCAO. Maximum stimulated force was not significantly different. No significant differences were found for muscle twitch properties, unilateral contractile properties, muscle fiber type percentages, or fiber size. However, the twitch/tetanus ratio was significantly increased in the MCAO group relative to sham. A small but significant increase in denervated NMJs and fiber-type grouping occurred in the contralesional genioglossus. Results suggest the primary cause of chronic lingual weakness after stroke is impaired muscle activation rather than a deficit of force generating capacity in lingual muscles. Increased fiber type grouping and denervated NMJs in the contralesional genioglossus suggest partial reinnervation of muscle fibers may have preserved force generating capacity, but not optimal activation patterns.

Specific strength and voluntary muscle activation in young and elderly women and men

1999 ◽  
Vol 87 (1) ◽  
pp. 22-29 ◽  
Author(s):  
Jane A. Kent-Braun ◽  
Alexander V. Ng
Keyword(s):  
Muscle Activation ◽  
Elderly Women ◽  
Activity Level ◽  
Central Activation ◽  
Force Development ◽  
Central Activation Ratio ◽  
Voluntary Muscle ◽  
Specific Strength ◽  
Age Related ◽  
Activation Ratio

The extents to which decreased muscle size or activation are responsible for the decrease in strength commonly observed with aging remain unclear. Our purpose was to compare muscle isometric strength [maximum voluntary contraction (MVC)], cross-sectional area (CSA), specific strength (MVC/CSA), and voluntary activation in the ankle dorsiflexor muscles of 24 young (32 ± 1 yr) and 24 elderly (72 ± 1 yr) healthy men and women of similar physical activity level. Three measures of voluntary muscle activation were used: the central activation ratio [MVC/(MVC + superimposed force)], the maximal rate of voluntary isometric force development, and foot tap speed. Men had higher MVC and CSA than did women. Young men had higher MVC compared with elderly men [262 ± 19 (SE) vs. 197 ± 22 N, respectively], whereas MVC was similar in young and elderly women (136 ± 15 vs. 149 ± 16 N, respectively). CSA was greater in young compared with elderly subjects. There was no age-related impairment of specific strength, central activation ratio, or the rate of voluntary force development. Foot tap speed was reduced in elderly (34 ± 1 taps/10 s) compared with young subjects (47 ± 1 taps/10 s). These results suggest that isometric specific strength and the ability to fully and rapidly activate the dorsiflexor muscles during a single isometric contraction were unimpaired by aging. However, there was an age-related deficit in the ability to perform rapid repetitive dynamic contractions.

scholarly journals Quadriceps Muscle Function After Exercise in Men and Women With a History of Anterior Cruciate Ligament Reconstruction

2014 ◽  
Vol 49 (6) ◽  
pp. 740-746 ◽  
Author(s):  
Christopher M. Kuenze ◽  
Jay Hertel ◽  
Joseph M. Hart
Keyword(s):  
Ligament Reconstruction ◽  
Cruciate Ligament ◽  
Knee Extension ◽  
Maximal Voluntary Isometric Contraction ◽  
Men And Women ◽  
Central Activation Ratio ◽  
Continuous Exercise ◽  
History Of ◽  
Activation Ratio ◽  
Anterior Cruciate

Context : Sex differences in lower extremity neuromuscular function have been reported after anterior cruciate ligament reconstruction (ACLR). Research evidence supports different levels of fatigability in men and women and between patients with ACLR and healthy controls. The influence of sex on the response to continuous exercise in patients with ACLR is not clear. Objective : To compare quadriceps neuromuscular function after exercise between men and women with ACLR. Design : Descriptive laboratory study. Setting : Laboratory. Patients or Other Participants : Twenty-six active volunteers (13 men [50%]: age = 24.1 ± 4.4 years, height = 179.1 ± 9.8 cm, mass = 80.1 ± 9.4 kg, months since surgery = 43.5 ± 37.0; 13 women [50%]: age = 24.2 ± 5.6 years, height = 163.0 ± 5.9 cm, mass = 62.3 ± 8.3 kg, months since surgery = 45.8 ± 42.7) with a history of unilateral primary ACLR at least 6 months earlier. Intervention(s) : Thirty minutes of continuous exercise comprising 5 separate 6-minute cycles, including 5 minutes of uphill walking and 1 minute of body-weight squatting and step-ups. Main Outcome Measure(s) : Normalized knee-extension maximal voluntary isometric contraction torque, quadriceps superimposed-burst torque, and quadriceps central activation ratio before and after exercise. We performed separate 2 (sex: men, women) × 2 (time: preexercise, postexercise) repeated-measures analyses of variance for the 3 variables. Separate, independent-samples t tests were calculated to compare preexercise with postexercise change in all dependent variables between sexes. Results : A significant group-by-time interaction was present for knee-extension torque (P = .04). The percentage reduction in knee-extension maximal voluntary isometric contraction torque (men = 1.94%, women = −10.32%; P = .02) and quadriceps central activation ratio (men = −1.45%, women = −8.69%; P = .03) experienced by men was less than that observed in women. Conclusions : In the presence of quadriceps dysfunction, female participants experienced greater-magnitude reductions in quadriceps function after 30 minutes of exercise than male participants. This indicates a reduced ability to absorb knee-joint loads, which may have significant implications for reinjury and joint osteoarthritis in women after ACLR.

Quadriceps and Patient-Reported Function in ACL-Reconstructed Patients: A Principal Component Analysis

2019 ◽  
Vol 28 (1) ◽  
pp. 8-16 ◽  
Author(s):  
Grant E. Norte ◽  
Jay N. Hertel ◽  
Susan A. Saliba ◽  
David R. Diduch ◽  
Joseph M. Hart
Keyword(s):  
Muscle Function ◽  
Knee Extensor ◽  
Principal Component ◽  
Motor Threshold ◽  
Central Activation ◽  
Central Activation Ratio ◽  
Active Motor ◽  
Total Knee ◽  
Activation Ratio ◽  
Quadriceps Function

Context: Assessment of physical function for individuals after anterior cruciate ligament reconstruction (ACL-R) is complex and warrants the use of diverse evaluation strategies. To maximize the efficiency of assessment, there is a need to identify tests that provide the most meaningful information about this population. Objective: To investigate underlying constructs of quadriceps muscle function that uniquely describe aspects of performance in patients after ACL-R and establish clinical thresholds for measures able to classify patients with and without ACL-R. Design: Cross-sectional. Setting: Research laboratory. Patients (or Other Participants): Seventy-two patients with a primary, unilateral ACL-R (32 males and 40 females, age = 26.0 [9.3] y, time since surgery = 46.5 [58.0] mo) and 30 healthy controls (12 males and 18 females, age = 22.7 [4.6] y). Intervention(s): Quadriceps function was assessed bilaterally during 1 study visit. Main Outcome Measures: Isokinetic strength (peak torque, total work, and average power) at 90° and 180°/s, maximal voluntary isometric contraction torque, fatigue index, central activation ratio, Hoffmann reflex, and active motor threshold. Principal component analyses were performed for the involved limb, contralateral limb, and limb symmetry. Receiver–operator characteristic curve analyses were conducted to determine the diagnostic utility of each variable. Binary logistic regression was used to predict group membership (ACL-R vs healthy). Results: Three components of peripheral, central, and combined (peripheral and central) muscle function were identified, explaining 70.7% to 80.5% of variance among measures of quadriceps function. Total knee-extensor work at 90°/s (≥18.4 J/kg), active motor threshold (≥39.5%), and central activation ratio (≥94.7%) of the involved limb were strong predictors of patient status and correctly classified 83.5% of patients with ACL-R (P < .001). Conclusions: Unique constructs of peripheral, central, and combined muscle function exist in patients with ACL-R. Total knee-extensor work at 90°/s, active motor threshold, and central activation ratio consistently explained a significant portion of variance in measures of quadriceps function, demonstrated acceptable to excellent diagnostic utility, and predicted group membership with 72.8% to 83.5% accuracy.

scholarly journals Validity and Reliability of the Newly Developed Surface Electromyography Device for Measuring Muscle Activity during Voluntary Isometric Contraction

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Myung Hun Jang ◽  
Se Jin Ahn ◽  
Jun Woo Lee ◽  
Min-Hyung Rhee ◽  
Dasom Chae ◽  
...  
Keyword(s):  
Correlation Coefficient ◽  
Isometric Contraction ◽  
Surface Electromyography ◽  
Biceps Brachii ◽  
High Reliability ◽  
Intraclass Correlation ◽  
Rectus Femoris ◽  
Validity And Reliability ◽  
Maximal Voluntary Isometric Contraction ◽  
Developed Surface

Objective. The purpose of this study was to establish the validity and reliability of the newly developed surface electromyography (sEMG) device (PSL-EMG-Tr1) compared with a conventional sEMG device (BTS-FREEEMG1000). Methods. In total, 20 healthy participants (10 males, age 30.3 ± 2.9 years; 10 females, age 22.3 ± 2.7 years) were recruited. EMG signals were recorded simultaneously on two devices during three different isometric contractions (maximal voluntary isometric contraction (MVIC, 40% MVIC, 80% MVIC)). Two trials were performed, and the same session was repeated after 1 week. EMG amplitude recorded from the dominant biceps brachii (BB) and rectus femoris (RF) muscles was analyzed for reliability using intrasession intraclass correlation coefficient (ICC). Concurrent validity of the two devices was determined using Pearson’s correlation coefficient. Results. Nonnormalized sEMG data showed moderate to very high reliability for all three contraction levels (ICC = 0.832–0.937 (BB); ICC = 0.814–0.957 (RF)). Normalized sEMG values showed no to high reliability (ICC = 0.030–0.831 (BB); ICC = 0.547–0.828 (RF)). sEMG signals recorded by the PSL-EMG-Tr1 showed good to excellent validity compared with the BTS-FREEEMG1000, at 40% MVIC (r = 0.943 (BB), r = 0.940 (RF)) and 80% MVIC (r = 0.983 (BB); r = 0.763 (RF)). Conclusions. The PSL-EMG-Tr1 was performed with acceptable validity. Furthermore, the high accessibility and portability of the device are useful in adjusting the type and intensity of exercise.

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