Voluntary muscle activation varies with age and muscle group

2002 ◽  
Vol 93 (2) ◽  
pp. 457-462 ◽  
Author(s):  
Jennifer M. Jakobi ◽  
Charles L. Rice
Keyword(s):  
Muscle Activation ◽  
Age Groups ◽  
Young Men ◽  
Elbow Flexion ◽  
Muscle Group ◽  
Elbow Flexor ◽  
Elbow Flexors ◽  
Voluntary Muscle ◽  
Muscle Groups ◽  
Old Men

The consistency and the number of attempts required to achieve maximal voluntary muscle activation have not been documented and compared between young and old adults. Furthermore, few studies have contrasted activation between functional pairs of muscle groups, and no study has tested upper limb muscles. The purpose of this study was to measure and compare voluntary muscle activation of the elbow flexors and extensors in young and old men over two separate test sessions. With the method of twitch interpolation to measure activation, six young (24 ± 1 yr) and six old (83 ± 4 yr) men performed five maximal voluntary contractions (MVC) during each session for each muscle group. Elbow flexion and extension MVC was less (43 and 47%, respectively) in the old men, yet the best maximal voluntary muscle activation was similar between age groups. However, when all 10 attempts at MVC were compared, the mean activation scores were slightly less (∼5%) in the elbow extensors but were ∼11% less ( P < 0.001) in the elbow flexors of old men, compared with young men. During the second session, there was a significant improvement of 13% ( P< 0.005) in mean elbow flexor activation in the old men. There were no session differences for either muscle group for the young men. The results indicate that, for aged men, elbow flexor maximal activation is achieved less frequently compared with elbow extensors, and thus mean activation for elbow flexors is less than for elbow extensors. However, if sufficient attempts are provided, the best effort for the old men is not different from that of the young men for either muscle group.

Perceived Exertion in Isometric Muscular Contractions Related to Age, Muscle, Force Level and Duration

1992 ◽  
Vol 36 (10) ◽  
pp. 712-716 ◽  
Author(s):  
Joseph M. Deeb ◽  
Colin G. Drury
Keyword(s):  
Perceived Exertion ◽  
Muscle Force ◽  
Age Groups ◽  
Muscle Group ◽  
Isometric Contractions ◽  
Age Group ◽  
Perceived Effort ◽  
Muscle Groups ◽  
Different Levels

This research was concerned with studying the development and growth of perceived effort of long-term isometric contractions as a function of muscle group (biceps vs quadriceps), of subjects with different age groups (20–29 vs. 50–59 years old) on long-term muscular isometric contractions (5 minutes) at different levels of %MVC (20, 40, 60, 80 and 100 %MVC). An experiment testing 20 subjects each performing 10 conditions (two muscle groups × five levels of %MVC) showed that the older age group reported Significantly higher perceived exertion at higher levels of %MVC and across time. Furthermore, subjects experienced a higher and faster increase in their perceived exertion when the level of %MVC and time increased.

Genetic and Environmental Influences on Expression of Recurrent Headache as a Function of the Reporting Age in Twins

Twin Research ◽  
2002 ◽  
Vol 5 (4) ◽  
pp. 277-286 ◽  
Author(s):  
Dan A. Svensson ◽  
Bo Larsson ◽  
Elisabet Waldenlind ◽  
Nancy L. Pedersen
Keyword(s):  
Environmental Influences ◽  
Age Groups ◽  
Young Men ◽  
Genetic Effects ◽  
Genetic Influences ◽  
Age Group ◽  
Environmental Variance ◽  
Recurrent Headache ◽  
Old Men ◽  
Additive Genetic Effects

AbstractTo explore age-related mechanisms in the expression of recurrent headache, we evaluated whether genetic and environmental influences are a function of the reporting age using questionnaire information that was gathered in 1973 for 15- to 47-year-old Swedish twins (n =12,606 twin pairs). Liability to mixed headache (mild migraine and tension-type headache) was explained by non-additive genetic influences (49%) in men aged from 15 to 30 years and additive genetic plus shared environmental influences (28%) in men aged from 31 to 47 years. In women, the explained proportion of variance, which was mainly due to additive genetic effects, ranged from 61% in adolescent twins to 12% in twins aged from 41 to 47 years, whereas individual specific environmental variance was significantly lower in twins aged from 15 to 20 years than in twins aged from 21 to 30 years. Liability to migrainous headache (more severe migraine) was explained by non-addi-tive genetic influences in men, 32% in young men and 45% in old men, while total phenotypic variance was significantly lower in young men than in old men. In women, the explained proportion of variance ranged from 91% in the youngest age group to 37% in the oldest age group, with major contributions from non-additive effects in young and old women (15–20 years and 41–47 years, respectively) and additive genetic effects in intermediate age groups (21–40 years). While total variance showed a positive age trend, genetic variance tended to be stable across age groups, whereas individual specific environmental variance was significantly lower in adolescent women as compared to older women.

Severe acute hypoxia impairs recovery of voluntary muscle activation after sustained submaximal elbow flexion

2021 ◽  
Author(s):  
Daniel J. McKeown ◽  
Chris J. McNeil ◽  
Emily J. Brotherton ◽  
Michael J. Simmonds ◽  
Justin J. Kavanagh
Keyword(s):  
Muscle Activation ◽  
Acute Hypoxia ◽  
Elbow Flexion ◽  
Voluntary Muscle

Does Performing Different Resistance Exercises for the Same Muscle Group Induce Non-homogeneous Hypertrophy?

2021 ◽  
Author(s):  
Bruna Daniella de Vasconcelos Costa ◽  
Witalo Kassiano ◽  
João Pedro Nunes ◽  
Gabriel Kunevaliki ◽  
Pâmela Castro-E-Souza ◽  
...  
Keyword(s):  
Muscle Length ◽  
Muscle Thickness ◽  
Relative Increase ◽  
Muscle Group ◽  
Elbow Flexors ◽  
Proximal Site ◽  
Resistance Exercises ◽  
Elbow Flexors And Extensors ◽  
Lateral Thigh ◽  
Muscle Groups

AbstractThe study aimed to compare the effect of performing the same or different exercises for a muscle group on resistance training (RT) sessions on muscle hypertrophy at different sites along muscle length. Twenty-two detrained men (23.3±4.1 years) were randomly allocated to the following groups: a group that performed the same exercises in all training sessions (N-VAR=11) or one that varied the exercises for the same muscle groups (VAR=11). All were submitted to 3 weekly sessions for nine weeks. Muscle thickness was assessed at the proximal, middle, and distal sites of the lateral and anterior thigh, elbow flexors, and extensors by B-mode ultrasound. The VAR group significantly increased all the sites analyzed (P<0.05). Furthermore, the proximal site of the lateral thigh showed a larger relative increase when compared to the middle site (P<0.05). In contrast, the N-VAR group were not revealed significant improvements only for the middle site of the lateral thigh and the proximal site of the elbow flexors (P>0.05). Our results suggest that to perform different resistance exercises can induce hypertrophy of all sites assessed in detrained young men.

scholarly journals Gender Differences in Shoulder Performance Fatiguability are Affected by Arm Position, Dominance and Muscle Group

2021 ◽  
Author(s):  
Cosmin Horobeanu ◽  
Samuel A. Pullinger ◽  
Julien Paulus ◽  
Cristian Savoia ◽  
Fui Yen Wong ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Frontal Plane ◽  
Comparative Investigation ◽  
Muscle Group ◽  
Abduction Angle ◽  
Shoulder Injuries ◽  
Rehabilitation Programs ◽  
Shoulder Muscles ◽  
Significant Difference ◽  
Muscle Groups

Abstract Background: Injury prevalence data, muscle strength, and fatiguability have shown differences between males and females. In addition, arm spatial orientation affects muscle activation and strength of the shoulder muscles, but little to no research has been conducted in relation to the shoulder rotator muscles comparing men and women. Therefore, the main aim of of this study was to perform a comparative investigation between two arm spatial orientations (45⁰ and 90⁰ of abduction in frontal plane) during a fatigue assessment of shoulder internal rotator (IR) and external rotator (ER) muscles. Secondly, the interaction of gender and dominance with muscular performance was assessed.Methods: Forty healthy sedentary participants, 20 males and 20 females took part in this study. Participants performed a fatigue resistance protocol consisting of 30 consecutive maximal concentric contractions of the IR and ER shoulder muscles in a supine position at a speed of 180⁰/s. The upper limb was abducted to an angle of 45⁰ or 90⁰ in frontal plane and each subject was tested on dominant and nom-dominant side, counterbalanced in order of administration. Performance measures of Induced Fatigue (IF), Cumulated Performance (C.Perf) and Best repetition (BR) were calculated and used for further analysis.Results: There was a significant difference in angle, with higher values observed in 90⁰ of abduction compared to 45⁰ of abduction for C.Perf by 6% and 7% for BR (P < 0.0005) in the ER. The dominant arm was significantly higher than the non-dominant arm for C.Perf with higher values of 9.7% at 90⁰ of abduction compared to 45⁰ of abduction (P = 0.017) and BR with higher values of 4.2% at 90⁰ of abduction compared to 45⁰ of abduction (P < 0.0005) in the ER in males. There was a significant difference in muscle group, with higher values observed in the IR for C.Perf (88.2%), BR (22.5%) and IF (36.9%); at 90⁰ of abduction compared to 45⁰ of abduction in males (P < 0.0005). Significantly higher values were observed for C.Perf in females between the dominant and non-dominant arm for the IR and ER (P < 0.0005). The females showed significantly lower values for C.Perf (47.74-55.10%) and BR (47.30-53.41%) in both muscle groups, both testing positions and in both limbs, when compared to males (P < 0.05)Discussion: It was established that an increase in the abduction angle will influence the strength of ER muscles in favour of the 90° angle without any differences observed in IR muscles. Males were found to produce approximately double the amount of work done compared to females, but the amount of induced fatigue was no different between both groups. Conclusion: Therefore, these findings are useful for clinicians throughout the monitoring of rehabilitation programs in sedentary individuals following shoulder injuries.

scholarly journals Alterations in Whole-Body Insulin Sensitivity Resulting From Repeated Eccentric Exercise of a Single Muscle Group: A Pilot Investigation

2015 ◽  
Vol 25 (4) ◽  
pp. 405-410 ◽  
Author(s):  
Javier T. Gonzalez ◽  
Martin J. Barwood ◽  
Stuart Goodall ◽  
Kevin Thomas ◽  
Glyn Howatson
Keyword(s):  
Insulin Resistance ◽  
Insulin Sensitivity ◽  
Physical Function ◽  
Eccentric Exercise ◽  
Muscle Group ◽  
Whole Body ◽  
Elbow Flexors ◽  
Pilot Investigation ◽  
Muscle Groups ◽  
Small Muscle

Unaccustomed eccentric exercise using large muscle groups elicits soreness, decrements in physical function and impairs markers of whole-body insulin sensitivity; although these effects are attenuated with a repeated exposure. Eccentric exercise of a small muscle group (elbow flexors) displays similar soreness and damage profiles in response to repeated exposure. However, it is unknown whether damage to small muscle groups impacts upon whole-body insulin sensitivity. This pilot investigation aimed to characterize whole-body insulin sensitivity in response to repeated bouts of eccentric exercise of the elbow flexors. Nine healthy males completed two bouts of eccentric exercise separated by 2 weeks. Insulin resistance (updated homeostasis model of insulin resistance, HOMA2-IR) and muscle damage profiles (soreness and physical function) were assessed before, and 48 h after exercise. Matsuda insulin sensitivity indices (ISIMatsuda) were also determined in 6 participants at the same time points as HOMA2-IR. Soreness was elevated, and physical function impaired, by both bouts of exercise (both p < .05) but to a lesser extent following bout 2 (time x bout interaction, p < .05). Eccentric exercise decreased ISIMatsuda after the first but not the second bout of eccentric exercise (time x bout interaction p < .05). Eccentric exercise performed with an isolated upper limb impairs whole-body insulin sensitivity after the first, but not the second, bout.

Normalized force, activation, and coactivation in the arm muscles of young and old men

2001 ◽  
Vol 91 (3) ◽  
pp. 1341-1349 ◽  
Author(s):  
C. S. Klein ◽  
C. L. Rice ◽  
G. D. Marsh
Keyword(s):  
Muscle Activation ◽  
Isometric Force ◽  
Strength Loss ◽  
The Elderly ◽  
Triceps Brachii ◽  
Cross Sectional ◽  
Age Related ◽  
Young Subjects ◽  
Muscle Groups ◽  
Old Men

The purpose of this study was to determine whether the loss of muscle strength in the elderly could be explained entirely by a decline in the physiological cross-sectional area (PCSA) of muscle. Isometric force, muscle activation (twitch interpolation), and coactivation (surface electromyograph) were measured during maximal voluntary contractions (MVCs) of the elbow flexors (EFs) and extensors (EEs) in 20 young (23 ± 3 yr) and 13 older (81 ± 6 yr) healthy men. PCSA was determined using magnetic resonance imaging, and normalized force (NF) was calculated as the MVC/PCSA ratio. The PCSA was smaller in the old compared with the young men, more so in the EEs (28%) compared with the EFs (19%) ( P < 0.001); however, the decline in MVC (∼30%) with age was similar in the two muscle groups. Muscle activation was not different between the groups, but coactivation was greater (5%) ( P < 0.001) in the old men for both muscles. NF was less (11%) in the EFs ( P < 0.01) and tended to be unchanged in the EEs of the old compared with young subjects. The relative maintenance of NF in the EEs compared with the EFs may be related to age-associated changes in the architecture of the triceps brachii muscle. In conclusion, although the decline in PCSA explained the majority of strength loss in the old men, additional factors such as greater coactivation or reduced specific tension also may have contributed to the age-related loss of isometric strength.

scholarly journals The reliability of Berger’s table in estimating 1-RM and 10-RM of the elbow flexor muscles in normal young adults

2001 ◽  
Vol 57 (2) ◽  
pp. 11-15
Author(s):  
A. O. Akinpelu ◽  
J. O. Iyaniwura ◽  
B. O. Ajagbe
Keyword(s):  
Young Adults ◽  
Muscle Group ◽  
Elbow Flexor ◽  
Regression Equations ◽  
Elbow Flexors ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles ◽  
The Right ◽  
Isotonic Strength

Isotonic strength training remains one of the methods of strengthening muscles, as it requires inexpensive materials. The method requires the determination of maximal isotonic strength or one repetition maximum [1-RM] and/or sub-maximal isotonic strength (2-RM - 10-RM) of a muscle group in order to know the appropriate resistance to subject the muscle group to, and to monitor strength gains by the muscle group. Berger’s table contains percentages for predicting 1-RM - 10-RM, and it is intended to improve the efficiency of determining isotonic muscle strength. The aim of this study was to investigate the reliability of Berger’s table in predicting 1-RM and 10-RM of the right elbow flexor muscles.1-RM and 10-RM were estimated using Berger’s table in 100 young adults following the determination of the number of repetitions that could be carried out against randomly selected weights. Weight adjustments were made to obtain the actual 1-RM and 10-RM. Data were subjected to regression analysis. A significant linear relationship exists between the estimated and actual values of 1-RM and 10-RM. Results also showed that Berger’s table explains 93% of 1-RM and 98% of 10-RM. It was concluded that Berger’s table is reliable in determining 1-RM and 10-RM of the elbow flexors in young healthy adults. Regression equations that may improve the accuracy of estimation were derived.

Submaximal isometric fatiguing exercise of the elbow flexors has no age-related effect on GABAB mediated inhibition

2021 ◽  
Author(s):  
Lavender A. Otieno ◽  
John G. Semmler ◽  
Ashleigh Elizabeth Smith ◽  
Simranjit K. Sidhu
Keyword(s):  
Biceps Brachii ◽  
Age Groups ◽  
Silent Period ◽  
Muscle Group ◽  
Cortical Inhibition ◽  
Elbow Flexors ◽  
Age Related ◽  
Submaximal Contraction ◽  
Fatiguing Exercise ◽  
Small Muscle

Age-related changes in the neuromuscular system can result in differences in fatigability between young and older adults. Previous research has shown that single joint isometric fatiguing exercise of small muscle results in an age-related compensatory decrease in GABAB mediated inhibition. However, this has yet to be established in a larger muscle group. In 15 young (22 ± 4 years) and 15 older (65 ± 5 years) adults, long interval cortical inhibition (LICI; 100 ms ISI) and corticospinal silent period (SP) were measured in the biceps brachii during a 5% EMG contraction using transcranial magnetic stimulation (TMS) before, during and after a submaximal contraction (30% MVC force) held intermittently to task failure. Both age groups developed similar magnitude of fatigue (~24% decline in MVC; P = 0.001) and ~28% decline in LICI (P = 0.001) post fatiguing exercise. No change in SP duration was observed during and immediately following fatigue (P = 0.909) but ~ 6% decrease was seen at recovery in both age groups (P<0.001)." Contrary to previous work in a small muscle, these findings suggest no age-related differences in GABAB mediated inhibition following single joint isometric fatiguing exercise of the elbow flexors, indicating that GABAB modulation with ageing may be muscle group dependent. Furthermore, variations in SP duration and LICI modulation during and post fatigue in both groups suggest that these measures are likely mediated by divergent mechanisms.

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