Laterality of Hand Grip and Elbow Flexion Power in Right Hand–Dominant Individuals

2009 ◽  
Vol 4 (3) ◽  
pp. 355-366 ◽  
Author(s):  
Hiroki Aoki ◽  
Shinichi Demura
Keyword(s):  
Gender Difference ◽  
Peak Power ◽  
Maximum Voluntary Contraction ◽  
Elbow Flexion ◽  
Voluntary Contraction ◽  
Power Ratio ◽  
Young Males ◽  
Left Hand ◽  
Hand Grip ◽  
Right Hand

Purpose:This study aimed to compare the laterality, and its gender difference, of hand grip and elbow flexion power according to load in right hand–dominant individuals.Results:The subjects were 15 healthy young males (age 22.1 ± 0.7 y, height 171.3 ± 3.4 cm, mass 64.5 ± 4.1 kg) and 15 healthy young females (age 22.4 ± 1.0 y, height 161.1 ± 3.0 cm, mass 55.4 ± 4.6 kg). Isotonic peak power was measured with 6 different loads ranging from 20% to 70% of maximum voluntary contraction (MVC) for grip and elbow flexion movements.Results:The peak power was significantly larger in males than in females in both movements (ratio, males:females was 58.1:49.4%). The dominant right hand had larger peak power in all loads for hand grip power (ratio, dominant:nondominant was 83.6:71.1%) and in loads of 20% to 50% MVC for elbow flexion power (88.7:85.7%) in both genders, confirming laterality in both movements. The peak power ratio of the dominant right hand to the nondomi-nant left hand was significantly larger in hand grip than in elbow flexion for all loads in females.Conclusion:Even though laterality was confirmed in both grip and elbow flexion, gender difference is more marked in hand grip.

scholarly journals Strength and Reaction Time Capabilities of New Zealand Polo Players and Their Association with Polo Playing Handicap

2019 ◽  
Vol 4 (3) ◽  
pp. 48 ◽  
Author(s):  
Regan Standing ◽  
Russ Best
Keyword(s):  
New Zealand ◽  
Reaction Time ◽  
Grip Strength ◽  
Statistical Significance ◽  
Correlation Coefficients ◽  
Hand Grip Strength ◽  
Left Hand ◽  
Hand Grip ◽  
Right Hand ◽  
Physical Attributes

Polo is an equestrian team sport consisting of four players per team, with level of play determined by cumulative player handicap (−2 to +10 goals), with a higher handicap denoting a better player. There is minimal literature investigating Polo players’ physical attributes, hence the understanding of the physical characteristics that may contribute to an improved handicap are unknown. This study sought to identify the relationship between pertinent strength measures (left and right hand grip strength; absolute and relative isometric mid-thigh pull) and reaction time in Polo handicap in 19 New Zealand Polo players, and ascertain whether handicap could be predicted by these measures. Correlation coefficients were expressed using R values, accompanying descriptors and 90% confidence intervals (C.I.). Variance explained was expressed via the R2 statistic, and statistical significance set at p < 0.05. Right hand grip strength, isometric mid-thigh pull values were found to significantly correlate to and explain variance within Polo player handicap (all moderate to large correlations; p < 0.05). Whereas left hand grip strength (R: 0.380; 90% C.I. −0.011 to 0.670) and reaction time (0.020; −0.372 to 0.406) were non-significant, moderate and trivial correlates and predictors of handicap respectively. Practically, these findings highlight the differing roles between rein and mallet hands of Polo players and emphasise the importance of a strong and stable platform when riding and striking the ball. Lack of association with reaction time may be explained in part by higher handicapped Polo players employing a more proactive approach to the game.

scholarly journals Rate modulation of human anconeus motor units during high-intensity dynamic elbow extensions

2016 ◽  
Vol 121 (2) ◽  
pp. 475-482 ◽  
Author(s):  
Brianna L. Cowling ◽  
Brad Harwood ◽  
David B. Copithorne ◽  
Charles L. Rice
Keyword(s):  
High Intensity ◽  
Peak Power ◽  
Maximum Voluntary Contraction ◽  
Motor Units ◽  
Voluntary Contraction ◽  
Elbow Extension ◽  
Concentric Contractions ◽  
Motor Unit Firing ◽  
Maximal Effort ◽  
Isometric Maximum Voluntary Contraction

Investigations of high-intensity isometric fatiguing protocols report decreases in motor unit firing rates (MUFRs), but little is known regarding changes in MUFRs following fatigue induced by high-intensity dynamic contractions. Our purpose was to evaluate MUFRs of the anconeus (an accessory elbow extensor) and elbow extension power production as a function of time to task failure (TTF) during high-velocity fatiguing concentric contractions against a moderately heavy resistance. Fine-wire intramuscular electrode pairs were inserted into the anconeus to record MUs in 12 male participants (25 ± 3 yr), over repeated sessions on separate days. MUs were tracked throughout a three-stage, varying load dynamic elbow extension protocol designed to extend the task duration for >1 min thereby inducing substantial fatigue. Mean MUFRs and peak power were calculated for three relative time ranges: 0–15% TTF (beginning), 45–60% TTF (middle) and 85–100% TTF (end). Mean duration of the overall fatigue protocol was ∼80 s. Following the protocol, isometric maximum voluntary contraction (MVC), highest velocity at 35% MVC load, and peak power decreased 37, 60, and 64% compared with baseline, respectively. Data from 20 anconeus MUs tracked successfully throughout the protocol indicated a reduction in MUFRs in relation to power loss from 36 Hz/160 W (0–15% TTF) to 28 Hz/97 W (45–60% TTF) to 23 Hz/43 W (85–100% TTF). During these high-intensity maximal effort concentric contractions, anconeus MUFRs decreased substantially (>35%). Although the absolute MUFRs were higher in the present study than those reported previously for other muscles during sustained high-intensity isometric tasks, the relative decrease in MUFRs was similar between the two tasks.

Maintenance of Uncued Isometric Contractions by Blind and Sighted

1979 ◽  
Vol 49 (2) ◽  
pp. 475-479
Author(s):  
Claudia G. Emes
Keyword(s):  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Isometric Contractions ◽  
Hand Grip ◽  
Significant Difference ◽  
Static Contractions

A comparison of 10 blind and 10 sighted subjects to a proprioceptive task was examined by analysis of response to maintenance of uncued static contractions. In attempting to sustain hand-grip tensions at specified percentages of maximum voluntary contraction, blind and sighted groups showed no significant difference in performance.

scholarly journals Effect of Elbow Flexion Angle on Cortical Voluntary Activation of the Non-Impaired Biceps: A 3 Days Repeated Sessions Study

2020 ◽  
Author(s):  
Thibault Roumengous ◽  
Paul A. Howell ◽  
Carrie L. Peterson
Keyword(s):  
Cortical Neurons ◽  
Maximum Voluntary Contraction ◽  
Motor Evoked Potential ◽  
Elbow Flexion ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Elbow Angle ◽  
Flexion Extension ◽  
Minimal Stimulation ◽  
Stimulation Of

ABSTRACTMeasurement of cortical voluntary activation (VA) with transcranial magnetic stimulation (TMS) is limited by technical challenges. One challenge is the difficulty in preferential stimulation of cortical neurons projecting to the target muscle and minimal stimulation of cortical neurons projecting to antagonists. Thus, the motor evoked potential (MEP) response to TMS in the target muscle compared to its primary antagonist may be an important parameter in the assessment of cortical VA. Modulating isometric elbow angle alters the magnitude of MEPs at rest. The purpose of this study was to evaluate the effect of isometric elbow flexion-extension angle on: 1) the ratio of biceps MEP relative to the triceps MEP amplitude across a range of voluntary efforts, and 2) cortical VA. Ten non-impaired participants completed three sessions wherein VA was determined using TMS at 45°, 90° and 120° of isometric elbow flexion, and peripheral electrical stimulation at 90° of elbow flexion. The biceps/triceps MEP ratio was greater in the more flexed elbow angle (120° flexion) compared to 90° during contractions of 50% and 75% of maximum voluntary contraction. Cortical VA assessed in the more extended elbow angle (45° flexion) was lower relative to 90° elbow flexion; this effect was dependent on the biceps/triceps MEP ratio. Cortical VA was sensitive to small changes in the linearity of the voluntary torque and superimposed twitch relationship, regardless of the elbow angle. Peripheral and cortical VA measures at 90° of elbow flexion were repeatable across three days. In conclusion, although the biceps/triceps MEP ratio was increased at a more flexed elbow angle relative to 90°, there was not a corresponding difference in cortical VA. Thus, increasing the MEP ratio via elbow angle did not affect estimation of cortical VA.

scholarly journals Increased Voluntary Activation of the Elbow Flexors Following a Single Session of Spinal Manipulation in a Subclinical Neck Pain Population

2019 ◽  
Vol 9 (6) ◽  
pp. 136 ◽  
Author(s):  
Mat Kingett ◽  
Kelly Holt ◽  
Imran Khan Niazi ◽  
Rasmus Wiberg Nedergaard ◽  
Michael Lee ◽  
...  
Keyword(s):  
Neck Pain ◽  
Repeated Measures ◽  
Spinal Manipulation ◽  
Maximum Voluntary Contraction ◽  
Elbow Flexion ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Elbow Flexors ◽  
Single Session ◽  
Post Intervention

To investigate the effects of a single session of spinal manipulation (SM) on voluntary activation of the elbow flexors in participants with subclinical neck pain using an interpolated twitch technique with transcranial magnetic stimulation (TMS), eighteen volunteers with subclinical neck pain participated in this randomized crossover trial. TMS was delivered during elbow flexion contractions at 50%, 75% and 100% of maximum voluntary contraction (MVC) before and after SM or control intervention. The amplitude of the superimposed twitches evoked during voluntary contractions was recorded and voluntary activation was calculated using a regression analysis. Dependent variables were analyzed with two-way (intervention × time) repeated measures ANOVAs. Significant intervention effects for SM compared to passive movement control were observed for elbow flexion MVC (p = 0.04), the amplitude of superimposed twitch (p = 0.04), and voluntary activation of elbow flexors (p =0.03). Significant within-group post-intervention changes were observed for the superimposed twitch (mean group decrease of 20.9%, p < 0.01) and voluntary activation (mean group increase of 3.0%, p < 0.01) following SM. No other significant within-group changes were observed. Voluntary activation of the elbow flexors increased immediately after one session of spinal manipulation in participants with subclinical neck pain. A decrease in the amplitude of superimposed twitch during elbow flexion MVC following spinal manipulation suggests a facilitation of motor cortical output.

scholarly journals Assessment of Student Learning of Operational Procedures in Electromagnetism

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Yikun Han ◽  
Qiaoyi Liu ◽  
Feipeng Pi ◽  
Lei Bao
Keyword(s):  
High School ◽  
High School Students ◽  
Conceptual Framework ◽  
Assessment Tool ◽  
School Students ◽  
Left Hand ◽  
Hand Grip ◽  
Right Hand ◽  
Assessment Of Student Learning ◽  
The Right

In the Chinese high school physics curriculum, three operational procedures are introduced in electromagnetism, namely right-hand grip rule, left-hand rule, and right-hand rule. This often led to confusion for student to differentiate these rules, and thus often focus on the surface characteristics of the problem or be misled by unrelated details. This study adopts the conceptual framework representation to model student understanding, and use it to guide the design of an assessment test on operational procedures in electromagnetism. The conceptual framework maps out the key concepts and their connections within a student’s knowledge structure. In this study, an assessment tool of operational procedures in electromagnetism was developed and tested among Chinese high school students and college freshmen. Based on the testing results of the assessment, students have memory behaviors when using the right-hand grip rule, the left-hand rule and the right-hand rule, and students’ understanding of electromagnetism can be summarized into three progression levels including novice-like, intermediate-mixed, and expert-like. Therefore, in order to help students develop integrated knowledge structures and deeper understanding, the cross product is an important central idea that needs to be emphasized in instruction.

scholarly journals An electromyographic assessment pilot study on the reliability of the forearm muscles during multi-planar maximum voluntary contraction grip and wrist articulation in young males

2021 ◽  
pp. 1-12
Author(s):  
Henry H. Hunter ◽  
Graeme G. Sorbie ◽  
Fergal M. Grace ◽  
Yaodong Gu ◽  
Wing-Kai Lam ◽  
...  
Keyword(s):  
Experimental Data ◽  
Clinical Practice ◽  
Pilot Study ◽  
Maximum Voluntary Contraction ◽  
Scientific Research ◽  
Voluntary Contraction ◽  
Young Males ◽  
Forearm Muscles

BACKGROUND: Electromyographic systems are widely used in scientific and clinical practice. The reproducibility and reliability of these measures are crucial when conducting scientific research and collecting experimental data.

Changes in Elbow Flexor Power with Intermittent Contractions and Various Loads

2008 ◽  
Vol 107 (2) ◽  
pp. 597-606
Author(s):  
Shunsuke Yamaji ◽  
Shinichi Demura ◽  
Hiroki Aoki ◽  
Kei Yamamoto
Keyword(s):  
Power Output ◽  
Peak Power ◽  
Muscle Power ◽  
Average Power ◽  
Elbow Flexion ◽  
Voluntary Contraction ◽  
Significant Difference ◽  
Average Power Output ◽  
Power Outputs ◽  
Intermittent Contractions

This study examined intermittent elbow flexion every 2 see. for 1 min. using various loads to study the properties of muscle power output and their relationship to peak power, defined as the maximum power output. 18 young men performed intermittent explosive elbow flexion (30 times × min.−1) using 30%, 40%, and 50% maximal voluntary contraction (MVC). The power outputs at 30% and 40% MVC slightly decreased (rate of decrease from peak power to average power output during the 26 to 30 contractions was about 5%). However, at 50% MVC, there was a marked decrease (33.6%). Power output for 8 contractions was significantly larger at 50% MVC than at 30% and 40% MVC, but after 9 contractions there was no significant difference between 40% and 50% MVC. In addition, after 27 contractions, 40% MVC was significantly larger than 30% and 50% MVC. That is, the tendency for power output to decrease differed among the various loads. The rate of decrease of power outputs showed no significant correlation with peak power for each load. Therefore, the rate of decrease or power output in intermittent contractions may help sustain the power output and cannot be evaluated as accurately as peak power.

Reducing Surgeon's Physical Stress in Minimally Invasive Neurosurgery

2019 ◽  
Vol 80 (05) ◽  
pp. 333-340
Author(s):  
Atsushi Nakayashiki ◽  
Tomohiro Kawaguchi ◽  
Atsuhiro Nakagawa ◽  
Fusako Mochizuki ◽  
Hiroaki Furukawa ◽  
...  
Keyword(s):  
Minimally Invasive ◽  
Muscle Fatigue ◽  
Maximum Voluntary Contraction ◽  
Physical Stress ◽  
Voluntary Contraction ◽  
Minimally Invasive Neurosurgery ◽  
Hand Grip ◽  
Surgical Devices ◽  
Surgical Device ◽  
Round Section

Background and Study Aims Various minimally invasive approaches are used in neurosurgery. Surgeons must perform nondynamic fine movements in a narrow corridor, so specially designed surgical devices are essential. Unsophisticated instruments may pose potential hazards. The purpose of this study was to assess the factors associated with muscle fatigue during minimally invasive neurosurgery and to investigate whether physical stress can be reduced by refining the devices used. Material and Methods Four physical aspects of a handpiece were investigated: torque of conduits (0.20, 0.28, and 0.37 kgf*cm), shape of hand grip (five types), angle of the nozzle (0, 20, and 40 degrees), and weight balance (neutral, proximal, and distal). To evaluate muscle fatigue, surface electromyography was recorded from the extensor carpi radialis muscle and flexor carpi radialis muscle during a geometric tracing task. The maximum voluntary contraction (MVC) of each muscle and %MVC (muscle contraction during a task/MVC × 100) were used as the indexes of muscle fatigue. Results The shape of the hand grip significantly reduced %MVC, which is associated with muscle fatigue. The torque of conduits and angle of the nozzle tended to reduce muscle fatigue but not significantly. Weight balance did not affect muscle fatigue. Based on these results, we made two refined models: model α (torque of conduits 0.2 kgf*cm, angle of nozzle 20 degrees, neutral balance, hand grip with a 2.9 × 2.0-cm oval section with angled finger rest), and model β (torque of conduits 0.2 kgf*cm, angle of nozzle 20 degrees, neutral balance, hand grip with a 2.9-cm round section with a curved finger rest). The %MVC was significantly decreased with both types (p < 0.05 and p < 0.01, respectively), indicating reduction of muscle fatigue. Conclusions The geometrically refined surgical device can improve muscle load during surgery and reduce the surgeon's physical stress, thus minimizing the risk of complications.

Sex Differences of Intermittent Elbow Flexion Power Using Various Loads

2008 ◽  
Vol 107 (2) ◽  
pp. 629-642
Author(s):  
Shunsuke Yamaji ◽  
Shinichi Demura ◽  
Kei Yamamoto
Keyword(s):  
Sex Difference ◽  
Power Output ◽  
Peak Power ◽  
Muscle Power ◽  
Elbow Flexion ◽  
Young Males ◽  
Significant Difference ◽  
Power Outputs ◽  
Increasing Load ◽  
Load Mass

This study was designed to clarity a sex difference in muscle power output properties by intermittent elbow flexion using various loads. 10 young males and 10 young females performed intermittent elbow flexion power outputs at 30 times × min.−1 for 1 min. using 30%, 40%, and 50% MVC loads. For both sexes, the decreasing peak power showed a similar trend between trials at all loads, and the reliability of each power parameter was good. The power outputs decreased largely with increasing load mass, and the power output in 50% MVC for males markedly decreased to the same level as that during the final phase in 30% MVC. Although the absolute value of regression coefficients for males became significantly larger with increasing load mass, that for females showed a significant difference only between 30% and 50% MVC. In 50% MVC, a large decrease for males was observed. Maximal peak power outputs were significantly larger with increasing load mass for both sexes, but for males more than for females. In both sexes, there were no significant differences among final powers of each load mass, and between total powers of 40% and 50% MVC. For the sum of every 5 consecutive power outputs, males showed significant differences between 30% and 40% MVC in all periods after the 6th contraction, but females did not and also between 30% and 50%. MVC in periods after the 16th contraction. In conclusion, it is considered that power outputs in the latter phases in 50% MVC are affected largely by muscle fatigue, and an intermittent power output test with 50% MVC can measure sustained power (fatigue resistance) in the latter phases, but there is a sex difference in the tendency to decrease.

Sign in / Sign up

Export Citation Format

Share Document