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.

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.

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.

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.

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

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 Electromyographic activation patterns during swallowing in older adults

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Jin Young Ko ◽  
Hayoung Kim ◽  
Joonyoung Jang ◽  
Jun Chang Lee ◽  
Ju Seok Ryu
Keyword(s):  
Older Adults ◽  
Viscous Fluid ◽  
Muscle Activation ◽  
Fatty Infiltration ◽  
Liquid Volume ◽  
Type I ◽  
Type Ii ◽  
Activation Patterns ◽  
Muscle Activation Patterns ◽  
Age Related

AbstractAge-related weakness due to atrophy and fatty infiltration in oropharyngeal muscles may be related to dysphagia in older adults. However, little is known about changes in the oropharyngeal muscle activation pattern in older adults. This was a prospective and experimental study. Forty healthy participants (20 older [> 60 years] and 20 young [< 60 years] adults) were enrolled. Six channel surface electrodes were placed over the bilateral suprahyoid (SH), bilateral retrohyoid (RH), thyrohyoid (TH), and sternothyroid (StH) muscles. Electromyography signals were then recorded twice for each patient during swallowing of 2 cc of water, 5 cc of water, and 5 cc of a highly viscous fluid. Latency, duration, and peak amplitude were measured. The activation patterns were the same, in the order of SH, TH, and StH, in both groups. The muscle activation patterns were classified as type I and II; the type I pattern was characterized by a monophasic shape, and the type II comprised a pre-reflex phase and a main phase. The oropharyngeal muscles and SH muscles were found to develop a pre-reflex phase specifically with increasing volume and viscosity of the swallowed fluid. Type I showed a different response to the highly viscous fluid in the older group compared to that in the younger group. However, type II showed concordant changes in the groups. Therefore, healthy older people were found to compensate for swallowing with a pre-reflex phase of muscle activation in response to increased liquid volume and viscosity, to adjust for age-related muscle weakness.

Age- and Activity-Related Differences in the Mechanisms Underlying Maximal Power Production in Young and Older Adults

2014 ◽  
Vol 30 (1) ◽  
pp. 12-20 ◽  
Author(s):  
Thomas Korff ◽  
Ann H. Newstead ◽  
Renate van Zandwijk ◽  
Jody L. Jensen
Keyword(s):  
Older Adults ◽  
Knee Flexion ◽  
Power Production ◽  
Activity Level ◽  
Maximum Power ◽  
Maximal Power ◽  
Joint Power ◽  
Age Related ◽  
Peak Knee ◽  
Active Adults

The purpose of this study was to examine the interactions between aging, activity levels and maximal power production during cycling. Participants were divided into younger adults (YA), older active adults (OA,) and older sedentary adults (OS). Absolute maximum power was significantly greater in YA compared with OS and OA; no differences were found between OA and OS. The age-related difference in maximum power was accompanied by greater absolute peak knee extension and knee flexion powers. Relative joint power contributions revealed both age- and activity-related differences. YA produced less relative hip extension power than older adults, regardless of activity level. The OS participants produced less relative knee flexion power than active adults, regardless of age. The results show the age-related decline in muscular power production is joint specific and that activity level can be a modifier of intersegmental coordination, which has implications for designing interventions for the aging population.

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