Child–adult differences in muscle strength and activation pattern during isometric elbow flexion and extension

Muscle strength and activation were compared in boys and men during maximal voluntary elbow flexion and extension contractions. Peak torque, peak rate of torque development (dτ/dτmax), rate of muscle activation, and electromechanical delay (EMD) were measured in 15 boys (aged 9.7 ± 1.6 years) and 16 men (aged 22.1 ± 2.8 years). During flexion, peak torque was significantly lower in boys than in men (19.5 ± 5.8 vs. 68.5 ± 11.0 Nm, respectively; p < 0.05), even when controlling for upper-arm cross-sectional area (CSA), and peak electromyography activity. Boys also exhibited a lower normalized dτ/dτmax (7.2 ± 1.7 vs. 9.5 ± 1.6 (Nm·s–1)·(Nm–1), respectively; p < 0.05) and a significantly longer EMD (75.5 ± 28.4 vs. 47.6 ± 17.5 ms, respectively). The pattern was similar for extension, except that group differences in peak torque were no longer significant when normalized for CSA. These results suggest that children may be less able to recruit or fully utilize their higher-threshold motor units, resulting in lower dimensionally normalized maximal torque and rate of torque development.

Download Full-text

Muscle Strength and Contractile Kinetics of Isometric Elbow Flexion in Girls and Women

Pediatric Exercise Science ◽

10.1123/pes.21.3.354 ◽

2009 ◽

Vol 21 (3) ◽

pp. 354-364 ◽

Cited By ~ 13

Author(s):

Bareket Falk ◽

Laura Brunton ◽

Raffy Dotan ◽

Charlotte Usselman ◽

Panagiota Klentrou ◽

...

Keyword(s):

Statistical Significance ◽

Elbow Flexion ◽

Peak Torque ◽

Muscle Size ◽

Cross Sectional ◽

Time To Peak ◽

Peak Rate ◽

Rate Of Torque Development ◽

Age Related ◽

Torque Development

Ten prepubertal girls and 15 young women were tested for maximal torque, peak rate of torque development, electro-mechanical delay (EMD), and time to peak rate of torque development during isometric elbow flexion. Absolute peak torque (17.0 ± 7.7 vs. 40.5 ± 8.3 Nm) and peak rate of torque development (105.9 ± 58.6 vs. 297.2 ± 113.0 Nm·s−1) were lower in the girls (p < .05). Normalized to muscle cross sectional area, torque was similar (8.27 ± 2.74 vs. 8.44 ± 1.65 Nm·cm−2), as was peak rate of torque development, normalized to peak torque (6.21 ± 1.94 vs. 7.30 ± 2.26 Nm·s−1/Nm). Both, time to peak rate of torque development (123.8 ± 36.0 vs. 110.5 ± 52.6 ms) and EMD (73.2 ± 28.6 vs. 51.9 ± 25.6 ms), were longer in the girls, although EMD’s difference only approached statistical significance (p = .06). Age-related isometric strength differences in females appear to be mainly muscle-size dependent. However, the time to peak torque and EMD findings suggest differential motor-unit activation which may functionally manifest itself in fast dynamic contractions.

Download Full-text

Do neuromuscular adaptations occur in endurance-trained boys and men?

Applied Physiology Nutrition and Metabolism ◽

10.1139/h10-031 ◽

2010 ◽

Vol 35 (4) ◽

pp. 471-479 ◽

Cited By ~ 16

Author(s):

Rotem Cohen ◽

Cam Mitchell ◽

Raffy Dotan ◽

David Gabriel ◽

Panagiota Klentrou ◽

...

Keyword(s):

Muscle Strength ◽

Endurance Training ◽

Muscle Activation ◽

Peak Torque ◽

Metabolic Effects ◽

Electromechanical Delay ◽

Time To Peak ◽

Neuromuscular Adaptations ◽

Health Related ◽

Isometric Torque

Most research on the effects of endurance training has focused on endurance training's health-related benefits and metabolic effects in both children and adults. The purpose of this study was to examine the neuromuscular effects of endurance training and to investigate whether they differ in children (9.0–12.9 years) and adults (18.4–35.6 years). Maximal isometric torque, rate of torque development (RTD), rate of muscle activation (Q30), electromechanical delay (EMD), and time to peak torque and peak RTD were determined by isokinetic dynamometry and surface electromyography (EMG) in elbow and knee flexion and extension. The subjects were 12 endurance-trained and 16 untrained boys, and 15 endurance-trained and 20 untrained men. The adults displayed consistently higher peak torque, RTD, and Q30, in both absolute and normalized values, whereas the boys had longer EMD (64.7 ± 17.1 vs. 56.6 ± 15.4 ms) and time to peak RTD (98.5 ± 32.1 vs. 80.4 ± 15.0 ms for boys and men, respectively). Q30, normalized for peak EMG amplitude, was the only observed training effect (1.95 ± 1.16 vs. 1.10 ± 0.67 ms for trained and untrained men, respectively). This effect could not be shown in the boys. The findings show normalized muscle strength and rate of activation to be lower in children compared with adults, regardless of training status. Because the observed higher Q30 values were not matched by corresponding higher performance measures in the trained men, the functional and discriminatory significance of Q30 remains unclear. Endurance training does not appear to affect muscle strength or rate of force development in either men or boys.

Download Full-text

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

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.6.1.94 ◽

2011 ◽

Vol 6 (1) ◽

pp. 94-105 ◽

Cited By ~ 21

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.

Download Full-text

Effects of Blood Flow Restriction During Rest From High-intensity Training on Muscle Hypertrophy and Muscle Strength

10.21203/rs.3.rs-515370/v1 ◽

2021 ◽

Author(s):

Tsukasa Tanaka ◽

Atsushi Kubota ◽

Hayao Ozaki ◽

Hirofumi Nishio ◽

Yuji Takazawa

Keyword(s):

Muscle Strength ◽

Muscle Hypertrophy ◽

Rating Scale ◽

Numerical Rating Scale ◽

Elbow Flexion ◽

Peak Torque ◽

Cross Sectional ◽

High Intensity Training ◽

Before And After ◽

Numerical Rating

Abstract Background: The present study investigated the effects of different timings of BFR during HIT on muscle hypertrophy, muscle strength, and pain during exercise.Methods: The study included 14 limbs from seven heathy males. Participants were divided into three groups: BFR during exercise (EX); BFR during rest (RE), and training only (CON). Participants performed elbow flexion exercises by BIODEX, two days / week for eight weeks. BFR was set at 120 mmHg pressure. Elbow flexor peak torque, and muscle cross-sectional area were measured, before and after the training period. The pain during exercise were measured during training.Results: The peak torque was significantly increased the RE and CON (p < 0.05), but no increase was observed in the EX. Exercise repetitions the RE (set 1, 26.5 ± 8.7 reps; set 2, 15.2 ± 8.0 reps; set 3, 13.1 ± 4.7 reps; set 4, 13.8 ± 6.3 reps) decreased two sets earlier than the CON (set 1, 28.0 ± 8.6 reps; set 2, 25.6 ± 7.5 reps; set 3, 24.4 ± 8.2 reps; and set 4, 23.8 ± 7.2 reps) (p < 0.01). The numerical rating scale was higher in the EX during exercise and in the RE during rest compared with the CON. However, the RE did not show exacerbated pain during exercise (p < 0.01).Conclusions: This present study showed that BFR during rest can lead to muscle hypertrophy and muscle strength with fewer exercise repetitions than training only. BFR during rest showed the greatest decreases in peak torque during exercise and did not exacerbate pain during exercise.

Download Full-text

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

Nicotine & Tobacco Research ◽

10.1093/ntr/ntz081 ◽

2019 ◽

Vol 22 (6) ◽

pp. 935-941 ◽

Cited By ~ 1

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.

Download Full-text

Maximal hip muscle strength and rate of torque development 6-30 months after hip arthroscopy for femoroacetabular impingement syndrome: A cross-sectional study

Journal of Science and Medicine in Sport ◽

10.1016/j.jsams.2021.05.006 ◽

2021 ◽

Author(s):

Lasse Ishøi ◽

Kristian Thorborg ◽

Joanne L. Kemp ◽

Michael P. Reiman ◽

Per Hölmich

Keyword(s):

Muscle Strength ◽

Femoroacetabular Impingement ◽

Hip Arthroscopy ◽

Cross Sectional Study ◽

Sectional Study ◽

Cross Sectional ◽

Rate Of Torque Development ◽

Hip Muscle ◽

Femoroacetabular Impingement Syndrome ◽

Torque Development

Download Full-text

Neuromuscular and Torque Kinetic Changes After 10 Months of Explosive Sport Training in Prepubertal Gymnasts

Pediatric Exercise Science ◽

10.1123/pes.2018-0034 ◽

2019 ◽

Vol 31 (1) ◽

pp. 77-84 ◽

Cited By ~ 1

Author(s):

Andrzej Kochanowicz ◽

Bartłomiej Niespodziński ◽

Jan Mieszkowski ◽

Stanisław Sawczyn ◽

Paweł Cięszczyk ◽

...

Keyword(s):

Elbow Flexion ◽

Peak Torque ◽

Sport Training ◽

Explosive Strength ◽

Rate Of Torque Development ◽

Before And After ◽

Prepubertal Boys ◽

Baseline Values ◽

Covariation Analysis ◽

Torque Development

Purpose: To determine neuromuscular and torque kinetic changes after 10 months of explosive sport training in the elbow of prepubertal gymnasts compared with untrained age-matched controls. Methods: In 15 young gymnasts (9.02 [0.41] y) and 15 age-matched untrained males (8.76 [0.51] y), the rate of torque development (RTD) using the Biodex System 4 and the coactivation index were evaluated using electromyography. Explosive strength variables were normalized to the peak torque. Measures were determined twice: before and after a 10-month period of gymnastic training. Covariation analysis was used to account for differences in baseline values between gymnasts and controls. Results: After 10 months of training, gymnasts demonstrated a significantly (P < .05) greater increase in normalized peak RTD values in elbow flexion compared with controls (7.76% vs 0.65%). Covariation analysis also revealed a significantly (P < .05) greater reduction in the coactivation index of elbow extension in the gymnasts (−7.81% [5.44%] points) compared with controls (−1.23% [6.32%] points). Conclusions: Compared with physical development alone, 10 months of explosive-strength training of young gymnasts is sufficient to increase torque-normalized RTD in the elbow joint of prepubertal boys. The RTD changes the authors observed in antagonistic elbow functions vary among gymnasts due to the specific demands of gymnastic training.

Download Full-text

GAMBARAN KEKUATAN OTOT PADA LANSIA DI BPLU SENJA CERAH PANIKI BAWAH

Jurnal e-Biomedik ◽

10.35790/ebm.3.1.2015.6618 ◽

2015 ◽

Vol 3 (1) ◽

Author(s):

Prisilia M. Pinontoan ◽

Sylvia R. Marunduh ◽

Herlina I. S. Wungouw

Keyword(s):

Muscle Strength ◽

Elderly Women ◽

Elbow Flexion ◽

Knee Extension ◽

Shoulder Abduction ◽

Elderly Men ◽

Cross Sectional ◽

Purposive Sampling ◽

Shoulder Flexion ◽

Cross Sectional Design

Abstract: The aim of this study was to find out the profile of muscle strength on elderly at BPLU Senja Cerah Paniki Bawah. This was a descriptive study with cross sectional design. There were 26 respondents who met the inclusion criteria, consisted of 10 elderly men and 16 elderly women. Respondents were selected by using purposive sampling method. The measurements of the muscle strength were done by using 1 RM method while doing elbow flexion, elbow extension, shoulder flexion, shoulder extension, shoulder abduction, knee flexion, knee extension and dorsoflexion. Data were analyzed manually and computerized then presented in tabular form. The result shows that the average muscle strength in elderly men were greater than women and the average muscle strength of respondents that were included in the age group 60-79 years old were greater than those in 80-99 years.Keywords: muscle strength, elderly.1 RMAbstrak: Tujuan dari penelitian ini yaitu untuk mengetahui gambaran kekuatan otot pada Lansia di BPLU Senja Cerah Paniki Bawah. Penelitian ini merupakan peneliltian deskriptif dengan rancangan potong lintang. Responden yang memenuhi kriteria inklusi terdiri dari 26 orang yang terdiri dari 10 orang laki-laki dan 16 orang perempuan. Sampel dipilih menggunakan cara purposive sampling. Kekuatan otot pada lansia diukur dengan menggunakan metode 1 RM yang diukur pada gerakan fleksi siku, ekstensi siku, fleksi bahu, ekstensi bahu, abduksi bahu, fleksi lutut, ekstensi lutut serta dorsofleksi. Data yang sudah didapatkan kemudian dikumpul dan diolah secara manual dan komputerisasi serta disajikan dalam bentuk tabel. Hasil penelitian menunjukkan rerata kekuatan otot responden laki-laki lebih besar dibanding perempuan dan rerata kekuatan responden yang termasuk dalam kelompok umur 60-79 tahun lebih besar dibanding kelompok umur 80-99 tahun.Kata kunci: kekuatan otot, lansia, 1 RM.

Download Full-text