Linkage of myostatin pathway genes with knee strength in humans

2004 ◽  
Vol 17 (3) ◽  
pp. 264-270 ◽  
Author(s):  
W. Huygens ◽  
M. A. Thomis ◽  
M. W. Peeters ◽  
J. Aerssens ◽  
R. Janssen ◽  
...  
Keyword(s):  
Linkage Analysis ◽  
Muscle Mass ◽  
Single Point ◽  
Young Male ◽  
Peak Torque ◽  
Knee Extension ◽  
Candidate Gene Approach ◽  
Potential Candidate ◽  
Cross Sectional ◽  
Knee Strength

This study was the first to explore the potential role of the myostatin ( GDF8) pathway in relation to muscle strength and estimated muscle cross-sectional area in humans using linkage analysis with a candidate gene approach. In young male sibs ( n = 329) 11 polymorphic markers in or near 10 candidate genes from the myostatin pathway were genotyped. Muscle mass was estimated by anthropometric measurements, and maximal knee strength was evaluated using isokinetic dynamometers (Cybex NORM). Single-point nonparametric variance components and linear quantitative trait locus regression linkage analysis methods were used. Linkage patterns were observed between knee extension and flexion peak torque with markers D2S118 ( GDF8), D6S1051 ( CDKN1A), and D11S4138 ( MYOD1), and a maximum LOD score of 2.63 ( P = 0.0002) was observed with D2S118. The ratios of peak torque over muscle and bone area of the midthigh of the lower contraction velocity (60°/s) showed more frequently significant LOD scores than the torques at high velocity (240°/s). Although myostatin is physiologically more related to muscle mass through possible effects of hyperplasia and hypertrophy than it is to strength, only two estimated muscle cross-sectional areas were marginally linked (LOD 1.06 and 1.07, P = 0.01) with marker D2S118 near GDF8 (2q32.2). The present results gave suggestive evidence that the myostatin pathway might be important for strength phenotypes, and GDF8, CDKN1A, and MYOD1 are potential candidate regions for a further and denser mapping with respect to these phenotypes.

scholarly journals ACTN3 Genotypes and Their Relationship with Muscle Mass and Function of Kosovan Adults

2021 ◽  
Vol 18 (17) ◽  
pp. 9135
Author(s):  
Arben Boshnjaku ◽  
Ermira Krasniqi ◽  
Harald Tschan ◽  
Barbara Wessner
Keyword(s):  
Muscle Mass ◽  
Handgrip Strength ◽  
Knee Extensor ◽  
Peak Torque ◽  
Knee Extension ◽  
Cross Sectional Study ◽  
Genotype Distribution ◽  
Cross Sectional ◽  
And Function ◽  
The Impact

Maintaining muscle mass and function is important throughout the lifestyle. While environmental factors such as physical activity and healthy nutrition are well investigated, the contribution of genetic factors is still controversial. Therefore, we aimed to investigate the impact of a common ACTN3 polymorphism (rs1815739) on body composition, handgrip strength, knee extensor peak torque, and physical performance (gait speed, 30-s arm curl, 30-s chair stand) in Kosovan adults. In total, 308 participants (160 females and 148 males, age range from 40 to 91 years) took part in this cross-sectional study. Genomic DNA was extracted from saliva and assessed for ACTN3 genotype distribution (41.5% of RR, 53.9% of RX and 4.6% of XX). Genotype allocation did not account for differences in any of the variables. Interestingly, female XX carriers were taller (p = 0.025) and had a higher isokinetic knee extension peak torque (p = 0.024) than the RX+RR group. In males, XX carriers were also taller (p = 0.049) and had a lower BMI (p = 0.026), but did not differ in any of the strength and performance parameters. These results indicate that the ACTN3 R577X polymorphism might exert a sex-specific impact on knee extensor peak torque and BMI.

Lower-Extremity Isokinetic Strength Profiling in Professional Rugby League and Rugby Union

2014 ◽  
Vol 9 (2) ◽  
pp. 358-361 ◽  
Author(s):  
Scott R. Brown ◽  
Matt Brughelli ◽  
Peter C. Griffiths ◽  
John B. Cronin
Keyword(s):  
Lower Extremity ◽  
Knee Flexion ◽  
Peak Torque ◽  
Rugby League ◽  
Knee Extension ◽  
Rugby Union ◽  
Joint Torque ◽  
Cross Sectional ◽  
Hip Strength ◽  
Hip Extension

Purpose:While several studies have documented isokinetic knee strength in junior and senior rugby league players, investigations of isokinetic knee and hip strength in professional rugby union players are limited. The purpose of this study was to provide lower-extremity strength profiles and compare isokinetic knee and hip strength of professional rugby league and rugby union players.Participants:32 professional rugby league and 25 professional rugby union players.Methods:Cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque and strength ratios of the dominant and nondominant legs during seated knee-extension/flexion and supine hip-extension/flexion actions at 60°/s.Results:Forwards from both codes were taller and heavier and had a higher body-mass index than the backs of each code. Rugby union forwards produced significantly (P < .05) greater peak torque during knee flexion in the dominant and nondominant legs (ES = 1.81 and 2.02) compared with rugby league forwards. Rugby league backs produced significantly greater hip-extension peak torque in the dominant and nondominant legs (ES = 0.83 and 0.77) compared with rugby union backs. There were no significant differences in hamstring-to-quadriceps ratios between code, position, or leg. Rugby union forwards and backs produced significantly greater knee-flexion-to-hip-extension ratios in the dominant and nondominant legs (ES = 1.49–2.26) than rugby union players.Conclusions:It seems that the joint torque profiles of players from rugby league and union codes differ, which may be attributed to the different demands of each code.

The Importance of Functional Hamstring/Quadriceps Ratios in Knee Osteoarthritis

2020 ◽  
Vol 29 (7) ◽  
pp. 866-870
Author(s):  
Özlem Aslan ◽  
Elif Balevi Batur ◽  
Jale Meray
Keyword(s):  
Patient Group ◽  
Critical Role ◽  
Peak Torque ◽  
Knee Extension ◽  
Cross Sectional Study ◽  
Control Group ◽  
Cross Sectional ◽  
Knee Oa ◽  
Hamstring Muscles ◽  
Grade 3

Context: Osteoarthritis (OA) is the most common chronic joint condition. Muscle dysfunction plays a critical role in the pathogenesis of knee OA. Objective: It has been suggested that the agonist–antagonist strength relationship for the knee may be better described by a functional hamstring/quadriceps (H/Q) ratio (Hconcentric/Qeccentric: the representative of knee flexion and Qeccentric/Hconcentric: the representative of knee extension). Therefore, in this study, the authors aimed to investigate this ratio and its importance for knee OA. Design: Cross-sectional study. Setting: Research clinic. Patients or Other Participant(s): Twenty healthy women and 20 women with grade 2 or grade 3 primer knee OA between the age of 50 and 80 years were included in this study. Intervention(s): Concentric and eccentric peak torque of quadriceps and hamstring muscles were evaluated for all individuals in patient and control groups with a Cybex isokinetic device. Functional H/Q ratio is calculated manually. Main Outcome Measure(s): Functional H/Q torque ratios were analyzed between the patients with OA and healthy individuals by using the isokinetic system. Results: The values of peak torque of hamstring concentric and eccentric and quadriceps concentric for the patient group were significantly lower than the control group (P < .05). No statistically important difference was found for quadriceps eccentric peak torque between 2 groups (P > .05). H/Q ratio for extension in the patient group was significantly higher than the control group (P < .05), whereas the H/Q ratio for flexion in the patient group was significantly lower than the control group (P < .05). Conclusion: This study showed the weakness of both quadriceps and hamstring muscles in patients with knee OA. The combination of functional H/Q ratio with hamstring and quadriceps muscles concentric and eccentric strength values can help to analyze the knee functions and develop preventive-therapeutic approaches for knee OA.

Relationship between Hip and Knee Strength and Knee Valgus during a Single Leg Squat

2006 ◽  
Vol 22 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Tina L. Claiborne ◽  
Charles W. Armstrong ◽  
Varsha Gandhi ◽  
Danny M. Pincivero
Keyword(s):  
Knee Flexion ◽  
Frontal Plane ◽  
Peak Torque ◽  
Knee Extension ◽  
Valgus Knee ◽  
Knee Motion ◽  
Knee Strength ◽  
Flexion Extension ◽  
Hip Abduction ◽  
Single Leg Squat

The purpose of this study was to determine the relationship between hip and knee strength, and valgus knee motion during a single leg squat. Thirty healthy adults (15 men, 15 women) stood on their preferred foot, squatted to approximately 60 deg of knee flexion, and returned to the standing position. Frontal plane knee motion was evaluated using 3-D motion analysis. During Session 2, isokinetic (60 deg/sec) concentric and eccentric hip (abduction/adduction, flexion/extension, and internal/external rotation) and knee (flexion/extension) strength was evaluated. The results demonstrated that hip abduction (r2= 0.13), knee flexion (r2= 0.18), and knee extension (r2= 0.14) peak torque were significant predictors of frontal plane knee motion. Significant negative correlations showed that individuals with greater hip abduction (r= –0.37), knee flexion (r= –0.43), and knee extension (r= –0.37) peak torque exhibited less motion toward the valgus direction. Men exhibited significantly greater absolute peak torque for all motions, excluding eccentric internal rotation. When normalized to body mass, men demonstrated significantly greater strength than women for concentric hip adduction and flexion, knee flexion and extension, and eccentric hip extension. The major findings demonstrate a significant role of hip muscle strength in the control of frontal plane knee motion.

scholarly journals Rate of Muscle Activation in Power-and Endurance-Trained Boys

2011 ◽  
Vol 6 (1) ◽  
pp. 94-105 ◽  
Author(s):  
Cameron Mitchell ◽  
Rotem Cohen ◽  
Raffy Dotan ◽  
David Gabriel ◽  
Panagiota Klentrou ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Peak Torque ◽  
Surface Emg ◽  
Knee Extension ◽  
Endurance Athletes ◽  
Group Differences ◽  
Electromechanical Delay ◽  
Cross Sectional ◽  
Isometric Knee Extension ◽  
Muscle Cross Sectional Area

Previous studies in adults have demonstrated power athletes as having greater muscle force and muscle activation than nonathletes. Findings on endurance athletes are scarce and inconsistent. No comparable data on child athletes exist.Purpose:This study compared peak torque (Tq), peak rate of torque development (RTD), and rate of muscle activation (EMG rise, Q30), in isometric knee extension (KE) and fexion (KF), in pre- and early-pubertal power- and endurance-trained boys vs minimally active nonathletes.Methods:Nine gymnasts, 12 swimmers, and 18 nonathletes (7–12 y), performed fast, maximal isometric KE and KF. Values for Tq, RTD, electromechanical delay (EMD), and Q30 were calculated from averaged torque and surface EMG traces.Results:No group differences were observed in Tq, normalized for muscle cross-sectional area. The Tq-normalized KE RTD was highest in power athletes (6.2 ± 1.9, 4.7 ± 1.2, 5.0 ± 1.5 N·m·s–1, for power, endurance, and nonathletes, respectively), whereas no group differences were observed for KF. The KE Q30 was significantly greater in power athletes, both in absolute terms and relative to peak EMG amplitude (9.8 ± 7.0, 5.9 ± 4.2, 4.4 ± 2.2 mV·ms and 1.7 ± 0.8, 1.1 ± 0.6, 0.9 ± 0.5 (mV·ms)/(mV) for power, endurance, and nonathletes, respectively), with no group differences in KF. The KE EMD tended to be shorter (P = .07) in power athletes during KE (71.0 ± 24.1, 87.8 ± 18.0, 88.4 ± 27.8 ms, for power, endurance, and nonathletes), with no group differences in KF.Conclusions:Pre- and early-pubertal power athletes have enhanced rate of muscle activation in specifically trained muscles compared with controls or endurance athletes, suggesting that specific training can result in muscle activation-pattern changes before the onset of puberty.

scholarly journals Skeletal Muscle Characteristics and Motor Performance After 2-Year Growth Hormone Treatment in Adults With Prader-Willi Syndrome

2014 ◽  
Vol 99 (5) ◽  
pp. 1816-1824 ◽  
Author(s):  
Claudio L. Lafortuna ◽  
Alessandro Minocci ◽  
Paolo Capodaglio ◽  
Luca A. Gondoni ◽  
Alessandro Sartorio ◽  
...  
Keyword(s):  
Body Mass ◽  
Motor Performance ◽  
Gh Deficiency ◽  
Handgrip Strength ◽  
Peak Torque ◽  
Knee Extension ◽  
Gh Treatment ◽  
Cross Sectional ◽  
Walking Tests ◽  
Exercise Endurance

Context: In adults with Prader-Willi syndrome (PWS), abnormal body composition with decreased lean body mass and skeletal muscle (SM) volume has been related to altered GH secretion and may possibly contribute to greatly reduced motor capacity. Objective: The scope of the study was to test the hypothesis that GH treatment has favorable effects on SM characteristics and motor performance in adults with PWS. Design, Setting, and Participants: Fifteen obese PWS subjects (nine males and six females; age range, 19–35 y; body mass index, 37.7–59.9 kg/m2) were investigated before and after 12 (GH12) and 24 (GH24) months of GH treatment. Main Outcome Measures: SM cross-sectional area and SM attenuation were determined with computed tomography at the lumbar and midthigh levels. Maximal isometric handgrip strength and isokinetic knee extension peak torque were measured. Motor performance was evaluated with different indoor walking tests, whereas exercise endurance was assessed with a treadmill incremental test to exhaustion. Results: A condition of severe GH deficiency was found in six patients (40%). GH treatment significantly increased lean body mass (GH12, P &lt; .05; GH24, P &lt; .05), reduced percentage of body fat (GH12, P &lt; .05; GH24, P &lt; .05), and augmented SM cross-sectional area and SM attenuation of both lumbar (GH12, P &lt; .01; GH24, P &lt; .001) and thigh muscles (GH24, P &lt; .05). Handgrip strength increased by 7% at GH12 (P &lt; .05) and by 13% at GH24 (P &lt; .001). Peak torque of knee extension extrapolated at zero angular velocity was significantly higher at GH24 (P &lt; .01), and exercise endurance rose by 13% (P &lt; .05) and 17% (P &lt; .05) before exhaustion at GH12 and GH24, respectively, whereas no change was detected with walking tests. No significant difference in the response to GH treatment was detected between patients with and without GH deficiency. Conclusion: Long-term GH treatment in adult PWS patients improves body composition and muscle size and quality and increases muscle strength and exercise tolerance independently from the GH secretory status.

ASSOCIATION OF MUSCLE STRENGTH AND GAIT SPEED WITH CROSS-SECTIONAL MUSCLE AREA DETERMINED BY MID-THIGH COMPUTED TOMOGRAPHY – A COMPARISON WITH SKELETAL MUSCLE MASS MEASURED BY DUAL-ENERGY X-RAY ABSORPTIOMETRY

2020 ◽  
pp. 1-8
Author(s):  
K. Tsukasaki ◽  
Y. Matsui ◽  
H. Arai ◽  
A. Harada ◽  
M. Tomida ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Physical Function ◽  
Muscle Mass ◽  
Gait Speed ◽  
Knee Extension ◽  
Muscle Area ◽  
Cross Sectional ◽  
Leg Extension ◽  
Knee Extension Strength ◽  
Leg Extension Power

Background: Muscle mass is often mentioned not to reflect muscle strength. For muscle mass assessment skeletal muscle index (SMI) is often used. We have reported that dual-energy X-ray absorptiometry (DXA)-derived SMI does not change with age in women, whereas the cross-sectional muscle area (CSMA) derived from computed tomography (CT) does. Objectives: The present study aimed to compare CT and DXA for the assessment of muscle tissue. Design & Setting: Cross-sectional study in the local residents. Participants: A total of 1818 subjects (age 40-89 years) randomly selected from community dwellers underwent CT examination of the right mid-thigh to measure the cross-sectional muscle area (CSMA). Skeletal muscle mass (SMM) was measured by DXA. The subjects performed physical function tests such as grip strength, knee extension strength, leg extension strength, and gait speed. The correlation between CT-derived CSMA and DXA-derived SMM along with their association with physical function was examined. Results: After controlling for related factors, the partial correlation coefficient of muscle cross-sectional area (CSA) with physical function was larger than that of DXA-derived SMM for gait speed in men (p=0.002) and knee extension strength in women (p=0.03). The partial correlation coefficient of quadriceps (Qc) CSA with physical function was larger than that of DXA-derived SMM for leg extension power in both sexes (p=0.01), gait speed in men (p<0.001), and knee extension strength in women (p<0.001). Conclusion: Mid-thigh CT-derived CSMA, especially Qc CSA, showed significant associations with grip strength, knee extension strength, and leg extension power, which were equal to or stronger than those of DXA-derived SMM in community-dwelling middle-aged and older Japanese people. The mid-thigh CSMA may be a predictor of mobility disability, and is considered to be useful in the diagnosis of sarcopenia.

Effects of lower limb unloading on skeletal muscle mass and function in humans

1991 ◽  
Vol 70 (4) ◽  
pp. 1882-1885 ◽  
Author(s):  
H. E. Berg ◽  
G. A. Dudley ◽  
T. Haggmark ◽  
H. Ohlsen ◽  
P. A. Tesch
Keyword(s):  
Skeletal Muscle ◽  
Muscle Mass ◽  
Lower Limb ◽  
Skeletal Muscle Mass ◽  
Bed Rest ◽  
Experimental Period ◽  
Peak Torque ◽  
Human Model ◽  
Cross Sectional ◽  
And Function

A model to simulate effects of microgravity on skeletal muscle mass and function in humans has been developed. Unilateral lower limb unloading that allowed ankle, knee, and hip joint mobility was conducted in six healthy men by suspending one lower limb and having the subjects walk on crutches. They performed maximal unilateral concentric or eccentric quadriceps actions at different angular velocities before and after 4 wk of suspension and after 4 days and after 7 wk of uncontrolled recovery. Peak torque (PT) and angle-specific torque (AST) were measured. Muscle cross-sectional area (CSA) and radiological density (RD) of the thigh were assessed by means of computerized tomography. Concentric and eccentric PT and AST across speeds decreased (P less than 0.05) by 22 and 16%, respectively, in response to unloading. At 4 days of recovery PT (-11%) and AST (-7%) were still lower (P less than 0.05) than before. Muscle CSA and RD decreased (P less than 0.05) by 7 and 6%, respectively. After 7 wk of recovery PT, AST, CSA, and RD had returned to normal. The control limb showed no changes over the experimental period except for a 6% decrease (P less than 0.05) in RD. It is suggested that this human model of unloading could serve to simulate effects of microgravity on skeletal muscle mass and function because reductions in muscle mass and strength were of similar magnitude to those produced by bed rest.

Profiling Isokinetic Strength by Leg Preference and Position in Rugby Union Athletes

2016 ◽  
Vol 11 (4) ◽  
pp. 500-507 ◽  
Author(s):  
Scott R. Brown ◽  
Matt Brughelli ◽  
Lee A. Bridgeman
Keyword(s):  
Lower Extremity ◽  
Peak Torque ◽  
Knee Extension ◽  
Rugby Union ◽  
Lower Extremity Injury ◽  
Cross Sectional ◽  
Hip Strength ◽  
Lower Extremity Muscle ◽  
Lower Extremity Strength ◽  
Sectional Analysis

Context:Muscle imbalances aid in the identification of athletes at risk for lower-extremity injury. Little is known regarding the influence that leg preference or playing position may have on lower-extremity muscle strength and asymmetry.Purpose:To investigate lower-extremity strength profiles in rugby union athletes and compare isokinetic knee- and hip-strength variables between legs and positions.Methods:Thirty male academy rugby union athletes, separated into forwards (n = 15) and backs (n = 15), participated in this cross-sectional analysis. Isokinetic dynamometry was used to evaluate peak torque, angle of peak torque, and strength ratios of the preferred and nonpreferred legs during seated knee extension/flexion and supine hip extension/flexion at 60°/s.Results:Backs were older (ES = 1.6) but smaller in stature (ES = –0.47) and body mass (ES = –1.3) than the forwards. The nonpreferred leg was weaker than the preferred leg for forwards during extension (ES = –0.37) and flexion (ES = –0.21) actions and for backs during extension (ES = –0.28) actions. Backs were weaker at the knee than forwards in the preferred leg during extension (ES = –0.50) and flexion (ES = –0.66) actions. No differences were observed in strength ratios between legs or positions. Backs produced peak torque at longer muscle lengths in both legs at the knee (ES = –0.93 to –0.94) and hip (ES = –0.84 to –1.17) than the forwards.Conclusions:In this sample of male academy rugby union athletes, the preferred leg and forwards displayed superior strength compared with the nonpreferred leg and backs. These findings highlight the importance of individualized athletic assessments to detect crucial strength differences in male rugby union athletes.

scholarly journals Cigarette Smoking Is Associated With Lower Quadriceps Cross-sectional Area and Attenuation in Older Adults

2019 ◽  
Vol 22 (6) ◽  
pp. 935-941 ◽  
Author(s):  
Elisa A Marques ◽  
Martine Elbejjani ◽  
Andrew W Frank-Wilson ◽  
Vilmundur Gudnason ◽  
Gunnar Sigurdsson ◽  
...  
Keyword(s):  
Older Adults ◽  
Cigarette Smoking ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Knee Extension ◽  
Muscle Area ◽  
Cross Sectional ◽  
Rate Of Torque Development ◽  
Muscle Attenuation ◽  
Torque Development

Abstract Introduction In addition to well-established links with cardiovascular and respiratory diseases, cigarette smoking may affect skeletal muscle; however, associations with quadriceps atrophy, density, and function are unknown. This study explored the associations of current and former smoking with quadriceps muscle area and attenuation as well as muscle force (assessed as knee extension peak torque) and rate of torque development—a measure of muscle power in older adults. Methods Data from 4469 older adults, aged 66–95 years at baseline in the Age, Gene/Environment Susceptibility-Reykjavik Study with measurements of thigh computed tomography, isometric knee extension testing, self-reported smoking history, and potential covariates were analyzed. Results Sex differences were observed in these data; therefore, our final analyses are stratified by sex. In men, both former smokers and current smokers had lower muscle area (with β= –0.10, 95% confidence interval [CI] = –0.17 to –0.03 and β = –0.19, 95% CI = –0.33 to –0.05, respectively) and lower muscle attenuation (ie, higher fat infiltration, β = –0.08, 95% CI = –0.16 to –0.01 and β = –0.17, 95% CI = –0.34 to –0.01, respectively) when compared with never smokers. Smoking status was not associated with male peak torque or rate of torque development. In women, current smoking was associated with lower muscle attenuation (β = –0.24, 95% CI = –0.34 to –0.13) compared to never smoking. Among female smokers (current and former), muscle attenuation and peak torque were lower with increasing pack-years. Conclusions Results suggest that cigarette smoking is related to multiple muscle properties at older age and that these relationships may be different among men and women. Implications This article presents novel data, as it examined for the first time the relationship between smoking and computed tomography-derived quadriceps muscle size (cross-sectional area) and attenuation. This study suggests that current cigarette smoking is related to higher muscle fat infiltration, which may have significant health implications for the older population, because of its known association with poor physical function, falls, and hip fractures.

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