Relationships among Muscle Endurance, Explosiveness, and Strength in Circum-Pubertal Boys

1998 ◽  
Vol 10 (1) ◽  
pp. 48-56 ◽  
Author(s):  
Kensaku Suei ◽  
Leslie McGillis ◽  
Randy Calvert ◽  
Oded Bar-Or
Keyword(s):  
Body Mass ◽  
Vertical Jump ◽  
Peak Torque ◽  
Knee Extension ◽  
Muscle Performance ◽  
Muscle Endurance ◽  
Total Work ◽  
Endurance Strength ◽  
Isometric Knee Extension ◽  
Pubertal Boys

We assess relationships among muscle endurance, strength, and explosiveness in forty-eight 9.6- to 17.0-year-old males divided into 3 maturational groups (Tanner Stages I, II-IV, and V). Peak torque during isometric knee extension and flexion was averaged to reflect strength. Mechanical power in the Sargent vertical jump was taken as explosiveness, and total work in the Wingate test reflected muscle endurance. Correlations (3 groups combined) among the variables, expressed in absolute terms, were r = .82 to .92, but only -.11 to .70 when expressed per body mass or lean thigh size. These correlations were distinctly lower in the Tanner V boys than in the 2 less-mature groups, which may suggest that specialization into discrete muscle performance characteristics does not occur before late puberty.

Maximum Power During Vertical Jump and Isometric Knee Extension Torque Alter Mobility Performance: A Cross-Sectional Study of Healthy Individuals

PM&R ◽  
2015 ◽  
Vol 8 (1) ◽  
pp. 19-27 ◽  
Author(s):  
Atsuhiro Tsubaki ◽  
Masayoshi Kubo ◽  
Ryosaku Kobayashi ◽  
Hirofumi Jigami ◽  
Kazuhiro Sugawara ◽  
...  
Keyword(s):  
Vertical Jump ◽  
Knee Extension ◽  
Cross Sectional Study ◽  
Maximum Power ◽  
Healthy Individuals ◽  
Sectional Study ◽  
Cross Sectional ◽  
Mobility Performance ◽  
Isometric Knee Extension

scholarly journals Isokinetic evaluation of knee muscles in soccer players: discriminant analysis

2015 ◽  
Vol 21 (5) ◽  
pp. 364-368 ◽  
Author(s):  
Bruno Fles Mazuquin ◽  
Ligia Maxwell Pereira ◽  
Josilainne Marcelino Dias ◽  
João Pedro Batista Junior ◽  
Mônica Angélica Cardoso Silva ◽  
...  
Keyword(s):  
Human Performance ◽  
Average Power ◽  
Peak Torque ◽  
Knee Extension ◽  
Soccer Players ◽  
Total Work ◽  
Wilks Lambda ◽  
Discriminant Analyses ◽  
Definition Of ◽  
Flexion And Extension

ABSTRACT Introduction: Muscle activity in soccer players can be measured by isokinetic dynamometer, which is a reliable tool for assessing human performance. Objectives: To perform isokinetic analyses and to determine which variables differentiate the under-17 (U17) soccer category from the professional (PRO). Methods: Thirty four players were assessed (n=17 for each category). The isokinetic variables used for the knee extension-flexion analysis were: peak torque (Nm), total work (J), average power (W), angle of peak torque (deg.), agonist/ antagonist ratio (%), measured for three velocities (60°/s, 120°/s and 300°/s), with each series containing five repetitions. Three Wilks' Lambda discriminant analyses were performed, to identify which variables were more significant for the definition of each of the categories. Results: The discriminative variables at 60°/s in the PRO category were: extension peak torque, flexion total work, extension average power and agonist/antagonist ratio; and for the U17s were: extension total work, flexion peak torque and flexion average power. At 120°/s for the PRO category the discriminant variables were: flexion peak torque and extension average power; for the U17s they were: extension total work and flexion average power. Finally at 300°/s, the variables found in the PRO and U17 categories respectively were: extension average power and extension total work. Conclusion: Isokinetic variables for flexion and extension knee muscles were able to significantly discriminate between PRO and U17 soccer players.

Age- and sex-associated differences in isokinetic knee muscle endurance between young children and adults

2009 ◽  
Vol 34 (4) ◽  
pp. 725-731 ◽  
Author(s):  
Mark B.A. De Ste Croix ◽  
Martine A. Deighan ◽  
Sebastien Ratel ◽  
Neil Armstrong
Keyword(s):  
Young Children ◽  
Peak Torque ◽  
Knee Extension ◽  
Total Work ◽  
Adult Males ◽  
Significant Interaction Effect ◽  
Peak Knee ◽  
Knee Muscle ◽  
Main Effects ◽  
Age And Sex

The purpose of this study was to examine the age- and sex-associated differences of repeated isokinetic knee extension and flexion. Fifty one participants, 30 young children (16 boys and 14 girls; aged 11 and 12 years) and 21 adults (9 males and 12 females; aged 18–35 years), agreed to participate in the study. Isokinetic concentric peak knee extension (PET) and flexion (PFT) torque were measured using a calibrated Biodex System 3. Participants performed 4 concentric extension–flexion cycles with maximum effort; after a 2 min rest, 50 continuous concentric cycles were performed at 1.56 rad·s–1. Total work of the extensors (WKEX) and flexors (WKFL) for the complete 50 repetitions was recorded. Average peak torque and average work for the first and last 3 repetitions were calculated to represent the percentage decline in torque and work. There were no significant differences between groups in the peak torque generated during the pretrial and endurance task, suggesting that participants gave a maximal effort at the start of the endurance task. There was a significant interaction effect in the total work done for both extensors and flexors, with adult males producing the greatest amount of work (6622 and 3444 J, respectively). When total work was divided by body mass, there were no significant sex effects, only main effects for group. The percentage decline for PET (40% vs. 60%), PFT (50% vs. 65%), WKET (43% vs. 61%), and WKFL (60% vs. 69%) demonstrated significant main effects for group, with greater fatigue in adults. We found no significant sex effect for fatigue. This study concludes that females do not resist fatigue from repeated isokinetic muscle actions to a greater extent than males, and that the greater fatigue in adults than in children is probably a product of greater initial torque production and work performed.

scholarly journals Isokinetic performance of knee flexor and extensor muscles in community-dwelling elderly women

2015 ◽  
Vol 28 (3) ◽  
pp. 555-562 ◽  
Author(s):  
Diogo C. Felício ◽  
Daniele S. Pereira ◽  
Bárbara Z. de Queiroz ◽  
Alexandra M. Assumpção ◽  
João M. D. Dias ◽  
...  
Keyword(s):  
Muscle Function ◽  
Elderly Women ◽  
Descriptive Analysis ◽  
Age Groups ◽  
Peak Torque ◽  
Community Dwelling ◽  
Muscle Performance ◽  
Total Work ◽  
Isokinetic Dynamometer ◽  
Extensor Muscles

AbstractIntroduction The isokinetic dynamometer enables accurate assessment of muscle function. In Brazil, few studies have assessed the isokinetic muscle performance in older adults making interpretation and comparison of results with other studies.Objectives To conduct a descriptive analysis of the performance of the muscle flexor and extensor muscles of the knee joint in elderly community and compare the performance between the age groups 65-74 years and 75 years or more.Methods This is a cross sectional observational study with a convenience sample of 229 elderly community. For the analysis of muscle performance was used isokinetic dynamometer (Biodex System 3 Pro™) in the angular velocities of 60 °/s and 180 °/s. The variables evaluated were peak torque, peak torque normalized by body weight, total work normalized by body mass, total work, average power and agonist/antagonist ratio. Descriptive analysis was used to characterize the sample. For comparison between age groups was used Student's t-test with α = 0.05.Results The elderly women with older age showed a statistically significant decrease in most of the variables (p < 0.05) except for the agonist and antagonist knee (p = 0.398).Conclusions The isokinetic was a sensitive tool to characterize the modifications caused by aging on muscle function. Elderly with results below the lower limits of the confidence intervals for all variables certainly has a decreased strength for the age group evaluated and must be addressed therapeutically. The results can be used as a benchmark in clinical practice and future research.

Effects of Hydraulic Resistance Strength Training on Isokinetic Measures of Leg Strength in Men with Mental Retardation

1995 ◽  
Vol 12 (4) ◽  
pp. 377-387 ◽  
Author(s):  
Rory Suomi ◽  
Paul R. Surburg ◽  
Peter Lecius
Keyword(s):  
Mental Retardation ◽  
Hydraulic Resistance ◽  
Peak Torque ◽  
Knee Extension ◽  
The Other ◽  
Isokinetic Strength ◽  
Total Work ◽  
Trained Subjects ◽  
Leg Strength ◽  
Hip Abduction

The purpose of this study was to determine the effects of hydraulic resistance (HR) training on total work and peak torque measures of isokinetic strength for tests of knee extension and hip abduction on men with mental retardation (MR). The subjects, 22 men with mild to moderate MR, were randomly assigned to two groups; 11 subjects trained three times a week for 12 weeks using HR exercise machines, while the other 11 served as controls. Prior to and after the 12 weeks of training, all subjects were assessed on isokinetic tests of knee extension at 60 deg/s and hip abduction at 30 deg/s. The strength trained subjects exhibited significant increases in total work scores on knee extension and hip abduction tests for both legs ranging from 25.0 to 177.1%. Significant increases ranging from 50.1 to 82.7% were also noted on two of the four peak torque measures. The control subjects did not exhibit significant changes in total work or peak torque scores on either muscle test between test sessions.

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.

Effect of strength training combined with antioxidant supplementation on muscular performance

2018 ◽  
Vol 43 (8) ◽  
pp. 775-781 ◽  
Author(s):  
Maurilio T. Dutra ◽  
Sávio Alex ◽  
Marcio Rabelo Mota ◽  
Nathalia B. Sales ◽  
Lee E. Brown ◽  
...  
Keyword(s):  
Strength Training ◽  
Randomized Study ◽  
Muscle Thickness ◽  
Peak Torque ◽  
Quadriceps Muscle ◽  
Muscle Performance ◽  
Control Group ◽  
Total Work ◽  
Antioxidant Supplementation ◽  
Significant Group

This was a placebo-controlled randomized study that aimed to investigate the effects of strength training (ST) combined with antioxidant supplementation on muscle performance and thickness. Forty-two women (age, 23.8 ± 2.7 years; body mass, 58.7 ± 11.0 kg; height, 1.63 ± 0.1 m) were allocated into 3 groups: vitamins (n = 15), placebo (n = 12), or control (n = 15). The vitamins and placebo groups underwent an ST program, twice a week, for 10 weeks. The vitamins group was supplemented with vitamins C (1 g/day) and E (400 IU/day) during the ST period. Before and after training, peak torque (PT) and total work (TW) were measured on an isokinetic dynamometer, and quadriceps muscle thickness (MT) was assessed by ultrasound. Mixed-factor ANOVA was used to analyze data and showed a significant group × time interaction for PT and TW. Both the vitamins (37.2 ± 5.4 to 40.3 ± 5.6 mm) and placebo (39.7 ± 5.2 to 42.5 ± 5.6 mm) groups increased MT after the intervention (P < 0.05) with no difference between them. The vitamins (146.0 ± 29.1 to 170.1 ± 30.3 N·m) and placebo (158.9 ± 22.4 to 182.7 ± 23.2 N·m) groups increased PT after training (P < 0.05) and PT was higher in the placebo compared with the control group (P = 0.01). The vitamins (2068.3 ± 401.2 to 2295.5 ± 426.8 J) and placebo (2165.1 ± 369.5 to 2480.8 ± 241.3 J) groups increased TW after training (P < 0.05) and TW was higher in the placebo compared with the control group (P = 0.01). Thus, chronic antioxidant supplementation may attenuate peak torque and total work improvement in young women after 10 weeks of ST.

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.

THE EFFECTS OF HIGH ADIPOSITY ON CONCENTRIC AND ECCENTRIC MUSCLE PERFORMANCE OF UPPER AND LOWER LIMB MUSCULATURE IN YOUNG AND OLD ADULTS

2021 ◽  
Author(s):  
Sharn Shelley ◽  
Rob S James ◽  
Steven James Eustace ◽  
Emma Eyre ◽  
Jason Tallis
Keyword(s):  
Older Adults ◽  
Body Mass ◽  
Muscle Function ◽  
Handgrip Strength ◽  
Peak Torque ◽  
Muscle Performance ◽  
Muscle Quality ◽  
Upper Body ◽  
Age Related ◽  
The Impact

The present study uniquely examined the influence of old age and adiposity on maximal concentric and eccentric torque and fatigue of the elbow (EF, EE) and knee (KF, KE) flexors and extensors. 40 males were recruited and categorised into young (n=21, 23.7±3.4) and old (n=19, 68.3±6.1) and then further into normal (young = 16.9±2.5%, old = 20.6±3.1%) and high adiposity (young = 28.9±5.0%, old = 31.3±4.2%) groups. Handgrip strength, sit-to-stand performance, and isokinetic assessments of peak torque at 60°, 120° and 180° s-1 were measured. Older men produced significantly less concentric and eccentric peak torque (P<0.016) but this was not influenced by adiposity (P>0.055). For KE and KF, high adiposity groups demonstrated reduced peak torque normalised to body mass (P<0.021), and muscle and contractile mode specific reduction in torque normalised to segmental lean mass. Eccentric fatigue resistance was unaffected by both age and adiposity (P>0.30) and perceived muscle soreness, measured up to 72 hours post, was only enhanced in the upper body of the young group following eccentric fatigue (P=0.009). Despite the impact of adiposity on skeletal muscle function being comparable between ages, these results suggest high adiposity will have greater impact on functional performance of older adults. Novelty: •Irrespective of age, high adiposity may negatively impact force to body mass ratio and muscle quality in a muscle and contractile mode specific manner. •Whilst the magnitude of adiposity effects is similar across ages, the impact for older adults will be more substantial given the age-related decline in muscle function.

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