Handedness but not dominance influences variability in endurance time for sustained, submaximal contractions

2012 ◽  
Vol 108 (5) ◽  
pp. 1501-1510 ◽  
Author(s):  
Nicole M. Gordon ◽  
Thorsten Rudroff ◽  
Joel A. Enoka ◽  
Roger M. Enoka
Keyword(s):  
Position Control ◽  
Voluntary Contraction ◽  
Hand Dominance ◽  
Endurance Time ◽  
Left Handed ◽  
Position Task ◽  
Target Force ◽  
Left And Right ◽  
The Difference ◽  
And Task

The purpose of this study was to compare endurance time and accompanying neuromuscular adjustments when left- and right-handed subjects used the dominant and nondominant arms to sustain submaximal contractions that required either force or position control. Ten left-handed and 10 right-handed healthy adults (21 ± 5 yr) participated in the study. Each subject exerted a similar net torque about the elbow joint during the force and position tasks to achieve a target force of 20% maximal voluntary contraction (MVC) force (56 ± 18 N). MVC force declined to a similar level immediately after task failure for left- and right-handed subjects (27 ± 13 vs. 25 ± 15%, P = 0.9). Endurance time for the position task was similar for the dominant and nondominant arms (task × dominance interaction, P = 0.17). Although the difference in endurance time between the two tasks was similar for left-handed (136 ± 165 s) and right-handed individuals (92 ± 73 s, task × handedness interaction, P = 0.38), there was greater variance in the ratio of the endurance times for the force and position tasks for left-handed (0.77) than right-handed subjects (0.13, P < 0.001; see Fig. 2 ). Furthermore, endurance time for the force and position tasks was significantly correlated for right-handed subjects ( r2 = 0.62, P < 0.001), but not for left-handed subjects ( r2 = 0.004, P = 0.79). Multiple regression analyses identified sets of predictor variables for each endurance time, and these differed with handedness and task. Hand dominance, however, did not influence endurance time for either group of subjects. These findings indicate that endurance times for the elbow flexors when performing submaximal isometric contractions that required either force or position control were not influenced by hand dominance but did depend on handedness.

scholarly journals Hand Dominance Effect During right (Accelerator) Throttle Gripping in Riding Simulation

2018 ◽  
Vol 7 (4.27) ◽  
pp. 141
Author(s):  
Nursalbiah Nasir ◽  
Asyraf Hakimi Azmi ◽  
Helmi Rashid
Keyword(s):  
Muscle Activation ◽  
Dominance Effect ◽  
Maximum Voluntary Contraction ◽  
Voluntary Contraction ◽  
Hand Dominance ◽  
Surface Electromyogram ◽  
Flexor Carpi Radialis ◽  
Left Handed ◽  
The Difference

This study investigated the difference in muscle activation of the muscles in right handed (RH) and left handed (LH) participants during riding of motorcycle simulator. Five participants (3 RH and 2 LH) with average age of 24.2±0.447 years old were recruited and they were requested to ride the simulator for certain period of times for three days. Two surface electromyogram (sEMG) electrodes were attached to right flexor carpi radialis (RFCR) and left flexor carpi radialis (LFCR) of the participants forearm. Electromyography (EMG) of flexor carpi radialis (FCR) are measured at both hands during the task. The results showed that muscle activation during first 5 minutes of riding task in day 1 of experiment (percentage of maximum voluntary contraction, %MVC) for RFCR in LH (non-dominant) participants was 97.4% and 87.7% in RH (dominant) participants. Therefore, this result indicates that non-dominant person needs to activate more muscle than RH person during control the accelerator throttle while riding.  

scholarly journals Motor unit activity in biceps brachii of left-handed humans during sustained contractions with two load types

2016 ◽  
Vol 116 (3) ◽  
pp. 1358-1365 ◽  
Author(s):  
Jeffrey R. Gould ◽  
Brice T. Cleland ◽  
Diba Mani ◽  
Ioannis G. Amiridis ◽  
Roger M. Enoka
Keyword(s):  
Motor Unit ◽  
Unit Activity ◽  
Position Control ◽  
Biceps Brachii ◽  
Motor Units ◽  
Motor Unit Activity ◽  
Time Interaction ◽  
Left Handed ◽  
Position Task ◽  
Task Time

The purpose of the study was to compare the discharge characteristics of single motor units during sustained isometric contractions that required either force or position control in left-handed individuals. The target force for the two sustained contractions (24.9 ± 10.5% maximal force) was identical for each biceps brachii motor unit ( n = 32) and set at 4.7 ± 2.0% of maximal voluntary contraction (MVC) force above its recruitment threshold (range: 0.5–41.2% MVC force). The contractions were not sustained to task failure, but the duration (range: 60–330 s) was identical for each motor unit and the decline in MVC force immediately after the sustained contractions was similar for the two tasks (force: 11.1% ± 13.7%; position: 11.6% ± 9.9%). Despite a greater increase in the rating of perceived exertion during the position task (task × time interaction, P < 0.006), the amplitude of the surface-recorded electromyogram for the agonist and antagonist muscles increased similarly during the two tasks. Nonetheless, mean discharge rate of the biceps brachii motor units declined more during the position task (task × time interaction, P < 0.01) and the variability in discharge times (coefficient of variation for interspike interval) increased only during the position task (task × time interaction, P < 0.008). When combined with the results of an identical study on right-handers (Mottram CJ, Jakobi JM, Semmler JG, Enoka RM. J Neurophysiol 93: 1381–1392, 2005), the findings indicate that handedness does not influence the adjustments in biceps brachii motor unit activity during sustained submaximal contractions requiring either force or position control.

Sex differences in the fatigability of arm muscles depends on absolute force during isometric contractions

2001 ◽  
Vol 91 (6) ◽  
pp. 2686-2694 ◽  
Author(s):  
Sandra K. Hunter ◽  
Roger M. Enoka
Keyword(s):  
Muscle Activation ◽  
Pressor Response ◽  
Voluntary Contraction ◽  
Elbow Flexor ◽  
Endurance Time ◽  
Muscle Activation Patterns ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles ◽  
Target Force ◽  
The Absolute

Women are capable of longer endurance times compared with men for contractions performed at low to moderate intensities. The purpose of the study was 1) to determine the relation between the absolute target force and endurance time for a submaximal isometric contraction and 2) to compare the pressor response and muscle activation patterns of men [26.3 ± 1.1 (SE) yr] and women (27.5 ± 2.3 yr) during a fatiguing contraction performed with the elbow flexor muscles. Maximal voluntary contraction (MVC) force was greater for men (393 ± 23 vs. 177 ± 7 N), which meant that the average target force (20% of MVC) was greater for men (79.7 ± 6.5 vs. 36.7 ± 2.0 N). The endurance time for the fatiguing contractions was 118% longer for women (1,806 ± 239 vs. 829 ± 94 s). The average of the rectified electromyogram (%MVC) for the elbow flexor muscles at exhaustion was similar for men (31 ± 2%) and women (30 ± 2%). In contrast, the heart rate and mean arterial pressure (MAP) were less at exhaustion for women (94 ± 6 vs. 111 ± 7 beats/min and 121 ± 5 vs. 150 ± 6 mmHg, respectively). The target force and change in MAP during the fatiguing contraction were exponentially related to endurance time ( r 2 = 0.68 and r 2 = 0.64, respectively), whereas the change in MAP was linearly related to target force ( r 2 = 0.51). The difference in fatigability of men and women when performing a submaximal contraction was related to the absolute contraction intensity and was limited by mechanisms that were distal to the activation of muscle.

Synchronization Error in Bilateral Simultaneous Flexion of Elbows

1975 ◽  
Vol 40 (2) ◽  
pp. 527-532 ◽  
Author(s):  
R. Nakamura ◽  
R. Taniguchi ◽  
Y. Oshima
Keyword(s):  
Warning Signal ◽  
Mirror Image ◽  
Sound Stimulus ◽  
Synchronization Error ◽  
Experimental Conditions ◽  
Synchronization Errors ◽  
Left Handed ◽  
Left And Right ◽  
The Difference ◽  
The Right

Using 7 left- and 7 right-handed subjects, the difference in time between left and right arms in the initiation of bilateral simultaneous flexion of elbows (synchronization error) was measured under three conditions: response to a sound stimulus with a warning signal, response to a sound stimulus without a warning signal, and self-initiated trial (option). The absolute value of synchronization errors depended upon experimental conditions. In conditions ‘with warning’ and ‘option’ the dominance shown in performance of left-handed subjects was the mirror-image of that shown by the right-handed subjects. The right biceps muscle responded faster in left-handed subjects and vice versa. Right-handed subjects showed rather a constant value in their dispersion of synchronization errors.

scholarly journals Laterality Does Not Affect the Depth Perception, but Interpupillary Distance

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Murat Aslankurt ◽  
Lokman Aslan ◽  
Adnan Aksoy ◽  
Murat Özdemir ◽  
Şenol Dane
Keyword(s):  
Outcome Measures ◽  
Depth Perception ◽  
Hand Dominance ◽  
Interpupillary Distance ◽  
Left Handed ◽  
Eye Dominance ◽  
Eye Examination ◽  
Left And Right ◽  
The Relationship ◽  
Positive Effect

In this study, which investigates the relationship between the levels of stereopsis with eye and hand dominance or interpupillary distance, 120 healthy young volunteers were investigated. Eye dominance was determined by modified Miles technique following a complete eye examination. Handedness was assessed with the Edinburgh handedness inventory. Interpupillary distance was measured with millimetric ruler. Stereoacuity was measured in both contour (Titmus test) and random dot (TNO test) stereograms. The stereopsis scores were evaluated in terms of hand or eye dominance. The correlation between stereopsis score and interpupillary distance was assessed. Main outcome measures were stereopsis scores according to hand and eye dominance. As a result, right- and left-handed individuals showed no differences in terms of stereopsis. No differences were found in stereopsis scores between right- and left-eye dominant people. There was a correlation between interpupillary distance and the depth of stereopsis (r=-0.248,P<0.05). Contrary to the expectation, the left and right dominant individuals did not differ in levels of stereopsis. Interpupillary distance has a positive effect on stereopsis.

The Effects of Handedness and Dominance on Motor Task Performance

2018 ◽  
Vol 62 (1) ◽  
pp. 1237-1241 ◽  
Author(s):  
Salim A. Mouloua ◽  
Mustapha Mouloua ◽  
Daniel S. McConnell ◽  
P. A. Hancock
Keyword(s):  
Task Performance ◽  
Motor Task ◽  
Dominant Hand ◽  
Hand Dominance ◽  
Prior Training ◽  
Future Studies ◽  
Fitts Law ◽  
Left Handed ◽  
Left And Right ◽  
Practical Implications

Two studies were carried out to examine the effects of user handedness and hand dominance on a motor task using Fitts’ law. Study one was designed to validate our previous findings showing differences between left- and right-handed participants who completed a mouse-pointing task using Fitts’ law. Results showed that right-handed participants were significantly faster than their left-handed peers, thereby validating our previous findings. Study two examined the effect of handedness and hand dominance on motor task performance by requiring two groups of left- and right-handed participants perform the motor task using both their dominant and non-dominant hands. Results showed a significant interaction between handedness and hand dominance on task performance. Right-handed participants were again significantly faster than their left-handed peers when both groups were using their dominant hand. However, left-handed participants were significantly faster than their right-handed peers when both groups were using their non-dominant hand. These findings might be attributed to prior training with computer mice designs that do not account for user handedness. Both theoretical and practical implications, as well as directions for future studies are also discussed.

A Dissociation between the Representation of Tool-use Skills and Hand Dominance: Insights from Left- and Right-handed Callosotomy Patients

2005 ◽  
Vol 17 (2) ◽  
pp. 262-272 ◽  
Author(s):  
Scott H. Frey ◽  
Margaret G. Funnell ◽  
Valerie E. Gerry ◽  
Michael S. Gazzaniga
Keyword(s):  
Left Hemisphere ◽  
Tool Use ◽  
Right Hemisphere ◽  
Hand Dominance ◽  
Conceptual Level ◽  
Left Hand ◽  
Left Handed ◽  
Contralateral Hand ◽  
Left And Right ◽  
The Right

The overwhelming majority of evidence indicates that the left cerebral hemisphere of right-handed humans is dominant both for manual control and the representation of acquired skills, including tool use. It is, however, unclear whether these functions involve common or dissociable mechanisms. Here we demonstrate that the disconnected left hemispheres of both right- and left-handed split-brain patients are specialized for representing acquired tool-use skills. When required to pantomime actions associated with familiar tools (Experiment 2), both patients show a right-hand (left hemisphere) advantage in response to tool names, pictures, and actual objects. Accuracy decreases as stimuli become increasingly symbolic when using the left hand (right hemisphere). Tested in isolation with lateralized pictures (Experiment 3), each patient's left hemisphere demonstrates a significant advantage over the right hemisphere for pantomiming tool-use actions with the contralateral hand. The fact that this asymmetry occurs even in a left-handed patient suggests that the left hemisphere specialization for representing praxis skills can be dissociated from mechanisms involved in hand dominance located in the right hemisphere. This effect is not attributable to differences at the conceptual level, as the left and right hemispheres are equally and highly competent at associating tools with observed pantomimes (Experiment 4).

Handedness and Dementia

1987 ◽  
Vol 65 (1) ◽  
pp. 207-210 ◽  
Author(s):  
Richard I. Naugle ◽  
Erin D. Bigler ◽  
C. Munro Cullum ◽  
Paul J. Massman
Keyword(s):  
Hand Dominance ◽  
Left Hand ◽  
Left Handed ◽  
Dementia Patients ◽  
The Difference ◽  
The Right

Some researchers have speculated that left-hand dominance is more prevalent among patients suffering from dementia of the Alzheimer's type which began prior to age 65 yr. and that, in those patients, the disease runs a more rapid course. In the present study, seven left-handed dementia patients were matched with seven right-handed dementia patients on the basis of age and years of education and were compared with regard to neuropsychological compromise. While the left-handed group was somewhat more impaired than the right-handed subjects, the difference between the two groups was not statistically significant.

Frequency Modulation of Motor Unit Discharge Has Task-Dependent Effects on Fluctuations in Motor Output

2005 ◽  
Vol 94 (4) ◽  
pp. 2878-2887 ◽  
Author(s):  
Carol J. Mottram ◽  
Evangelos A. Christou ◽  
François G. Meyer ◽  
Roger M. Enoka
Keyword(s):  
Motor Unit ◽  
Frequency Modulation ◽  
Discharge Rate ◽  
Motor Output ◽  
Unit Discharge ◽  
Rate Of Increase ◽  
Output Force ◽  
Position Task ◽  
Motor Unit Discharge ◽  
Target Force

The rate of change in the fluctuations in motor output differs during the performance of fatiguing contractions that involve different types of loads. The purpose of this study was to examine the contribution of frequency modulation of motor unit discharge to the fluctuations in the motor output during sustained contractions with the force and position tasks. In separate tests with the upper arm vertical and the elbow flexed to 1.57 rad, the seated subjects maintained either a constant upward force at the wrist (force task) or a constant elbow angle (position task). The force and position tasks were performed in random order at a target force equal to 3.6 ± 2.1% (mean ± SD) of the maximal voluntary contraction (MVC) force above the recruitment threshold of an isolated motor unit from the biceps brachii. Each subject maintained the two tasks for an identical duration (161 ± 93 s) at a mean target force of 22.4 ± 13.6% MVC. As expected, the rate of increase in the fluctuations in motor output (force task: SD for detrended force; position task: SD for vertical acceleration) was greater for the position task than the force task ( P < 0.001). The amplitude of the coefficient of variation (CV) and the power spectra for motor unit discharge were similar between tasks ( P > 0.1) and did not change with time ( P > 0.1), and could not explain the different rates of increase in motor output fluctuations for the two tasks. Nonetheless, frequency modulation of motor unit discharge differed during the two tasks and predicted ( P < 0.001) both the CV for discharge rate (force task: 1–3, 12–13, and 14–15 Hz; position task: 0–1, and 1–2 Hz) and the fluctuations in motor output (force task: 5–6, 9–10, 12–13, and 14–15 Hz; position task: 6–7, 14–15, 17–19, 20–21, and 23–24 Hz). Frequency modulation of motor unit discharge rate differed for the force and position tasks and influenced the ability to sustain steady contractions.

Kinematic contribution and synchronization of the trunk, hip, and knee during free-dynamic lifting

2003 ◽  
Vol 3 (2) ◽  
pp. 99-108
Author(s):  
Kermit G. Davis ◽  
Riley E. Splittstoesser ◽  
William S. Marras
Keyword(s):  
Whole Body ◽  
Knee Height ◽  
Squat Lifting ◽  
The Difference ◽  
Free Dynamic ◽  
Body Lifting ◽  
And Task ◽  
Kinematic Contribution ◽  
Stoop Lifting

Although there have been numerous studies evaluating the difference between stooped and squat lifting styles, there remains a lack of understanding of whole body kinematics during unrestricted lifting. The current study evaluated nine males and nine females while lifting two box weights (9.1 kg, 18.2 kg) from five origins below the waist (0, 19, 38, 57, and 76 cm above the floor) and from three task asymmetries (sagittally symmetric, 45° clockwise, 45° counter-clockwise). While the lifting style was significantly influenced by the height of lift origin and to a lesser extent gender, box weight, and task asymmetry, none of the conditions resulted in pure squat or stoop lifting style. However, for lifts above knee height, the lifting style resembled more of a stoop lift while lifts originating below knee height were more of a squat lift. As the origin moved closer to the floor, participants relied more on their hips to accomplish the sagittal flexion but overall adopted a more coordinated whole-body lifting style. All together, as more sagittal flexion is required, more joints are relied upon in a more coordinated effort. The current study indicates that caution needs to be exercised when applying results of pure squat or pure stoop lifting studies to free-style (realistic) lifting.

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