Effect of a manual screwdriver with a pistol-grip handle on maximum torque and muscle activity

2008 ◽  
Author(s):  
Hector J. Sanchez ◽  
Richard W. Marklin
Keyword(s):  
Muscle Activity ◽  
Maximum Torque

Bilateral tremor responses to unilateral loading and fatiguing muscle contractions

2013 ◽  
Vol 110 (2) ◽  
pp. 431-440 ◽  
Author(s):  
Justin J. Kavanagh ◽  
Andrew G. Cresswell ◽  
Surendran Sabapathy ◽  
Timothy J. Carroll
Keyword(s):  
Muscle Activity ◽  
Elbow Joint ◽  
Spillover Effect ◽  
Muscle Contractions ◽  
The Body ◽  
Emg Activity ◽  
Postural Tremor ◽  
Maximum Torque ◽  
Torque Generation ◽  
Maximal Effort

Although physiological tremor has been extensively studied within a single limb, tremor relationships between limbs are not well understood. Early investigations proposed that tremor in each limb is driven by CNS oscillators operating in parallel. However, recent evidence suggests that tremor in both limbs arises from shared neural inputs and is more likely to be observed under perturbed conditions. In the present study, postural tremor about the elbow joint and elbow flexor EMG activity were examined on both sides of the body in response to unilateral loading and fatiguing muscle contractions. Applying loads of 0.5, 1.0, 1.5, and 3.0 kg to a single limb increased tremor and muscle activity in the loaded limb but did not affect the unloaded limb, indicating that manipulating the inertial characteristics of a limb does not evoke bilateral tremor responses. In contrast, maximal-effort unilateral isometric contractions resulted in increased tremor and muscle activity in both the active limb and the nonactive limb without any changes in between-limb tremor or muscle coupling. When unilateral contractions were repeated intermittently, to the extent that maximum torque generation about the elbow joint declined by 50%, different tremor profiles were observed in each limb. Specifically, unilateral fatigue altered coupling between limbs and generated a bilateral response such that tremor and brachioradialis EMG decreased for the fatigued limb and increased in the contralateral nonfatigued limb. Our results demonstrate that activity in the nonactive limb may be due to a “spillover” effect rather than directly coupled neural output to both arms and that between-limb coupling for tremor and muscle activity is only altered under considerably perturbed conditions, such as fatigue-inducing contractions.

Myoelectric Activity Differences in Three Learning Sessions

2002 ◽  
Vol 16 (2) ◽  
pp. 92-96
Author(s):  
Tiina Ritvanen ◽  
Reijo Koskelo ◽  
Osmo H„nninen
Keyword(s):  
High School Students ◽  
Muscle Activity ◽  
Muscle Tension ◽  
Emg Activity ◽  
Traditional Learning ◽  
Myoelectric Activity ◽  
School Students ◽  
Language Laboratory ◽  
Upper Trapezius ◽  
Muscle Groups

Abstract This study follows muscle activity in three different learning sessions (computer, language laboratory, and normal classroom) while students were studying foreign languages. Myoelectric activity was measured in 21 high school students (10 girls, 11 boys, age range 17-20 years) by surface electromyography (sEMG) from the upper trapezius and frontalis muscles during three 45-min sessions. Root mean square (RMS) average from both investigated muscles was calculated. The EMG activity was highest in both muscle groups in the computer-aided session and lowest in the language laboratory. The girls had higher EMG activity in both investigated muscle groups in all three learning situations. The measured blood pressure was highest at the beginning of the sessions, decreased within 10 min, but increased again toward the end of the sessions. Our results indicate that the use of a computer as a teaching-aid evokes more constant muscle activity than the traditional learning situations. Since muscle tension can have adverse health consequences, more research is needed to determine optimal classroom conditions, especially when technical aids are used in teaching.

Investigating the effects of slipping on lumbar muscle activity, kinematics, and kinetics

2012 ◽  
Author(s):  
Ehsan Rashedi ◽  
Bochen Jia ◽  
Maury A. Nussbaum ◽  
Thurmon E. Lockhart
Keyword(s):  
Muscle Activity ◽  
Lumbar Muscle ◽  
Kinematics And Kinetics

The effects of personality type and stress on muscle activity during simulated work tasks

2003 ◽  
Author(s):  
Naomi F. Glasscock ◽  
Gary A. Mirka ◽  
Carolyn M. Sommerich ◽  
Katherine W. Klein
Keyword(s):  
Muscle Activity ◽  
Personality Type ◽  
Work Tasks

The effects of scaling height and scaling bar design on applied forces and bilateral muscle activity of the back and shoulders

2006 ◽  
Author(s):  
William Porter ◽  
Sean Gallagher ◽  
Carrie Reinholtz ◽  
Janet Torma-Krajewski
Keyword(s):  
Muscle Activity ◽  
Applied Forces
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