scholarly journals An electromyographic investigation of asymmetric lifting and moving of a load: III. Models for determining muscle activity based on anthropometric characteristics

2009 ◽  
Vol 19 (5) ◽  
pp. 404-412 ◽  
Author(s):  
Biman Das ◽  
Godfrey Mabaleka
1977 ◽  
Vol 4 (1) ◽  
pp. 17-22 ◽  
Author(s):  
Mary McF. Simpson

The changes in lip activity associated with retraction of the upper labial segment during treatment of Class II division 1 malocclusion were investigated electromyographically. In the lip seal position muscle activity of the circumoral muscles was much reduced after treatment, but the amount of reduction appeared to be unrelated to the amount of incisor retraction. In some cases lips which were judged to be incompetent before treatment were competent after treatment. Activity in the suprahyoid muscle group associated with upper incisor inclination and overjet when the lips were sealed was eliminated during swallowing.


1982 ◽  
Vol 49 (1) ◽  
pp. 11-15
Author(s):  
Elizabeth Boyd

This study investigated the effects of six different types of olfactory stimuli on the electromyographic activity of the masseter, upper trapezius, and biceps brachii muscles of 18 normal subjects. The presence of the stimuli had a significant effect on the masseter (p < .011) and the upper trapezius (p < .001) muscles, but not on the biceps brachii muscle. The type of stimulus and the order of presentation of the stimuli had no significant effect on any of the three muscles. Muscle activity was increased whether or not the subject considered the stimulus pleasant or unpleasant. The limitations of this study, the implications for treatment using olfactory stimuli, and suggestions for further study are presented.


2019 ◽  
Vol 10 (8) ◽  
pp. 1006-1014 ◽  
Author(s):  
Ram Haddas ◽  
Yigal Samocha ◽  
James Yang

Study Design: Prospective, concurrent-cohort study. Objectives: To determine the effects of volitional preemptive abdominal contraction (VPAC) on trunk control during an asymmetric lift in patients with recurrent low back pain (rLBP) and compare with matched controls. Methods: Thirty-two rLBP patients and 37 healthy controls performed asymmetric lifting with and without VPAC. Trunk, pelvis, and hip biomechanical along with neuromuscular activity parameters were obtained using 3-dimensional motion capture and electromyography system. Hypotheses were tested using analysis of variance. Results: The VPAC resulted in significantly reduced muscle activity across all trunk extensor muscles in both groups (M ± SD, 6.4% ± 8.2% of maximum contraction; P ≤ .005), and reduced trunk side flexion (1.4° ± 5.1° smaller; P ≤ .005) and hip abduction (8.1° ± 21.1° smaller; P ≤ .003). rLBP patients exhibited reduced muscle activity in external oblique (12.3% ± 5.5% of maximum contraction; P ≤ .012), as well as decreased hip flexion (4.7°, P ≤ .008) and hip abduction (5.2°, P ≤ .001) at the final position of lifting in comparison with healthy controls. Conclusions: The results of this study defend the recommendation that the use of a VPAC increase spine stability during an asymmetrical loading task. Our results provide an indication that a VPAC strategy that is achieved during an asymmetric lifting decreases exposure for lumbar spine injury and instability. Spine care providers and ergonomists can use this information when designing neuromuscular control training programs, both for healthy individuals aimed at prevention of injury, as well as those with a history of rLBP, aimed at full functional recovery and protection from future injury.


Author(s):  
Carolyn M. Sommerich ◽  
William S. Marras ◽  
Mohamad Parnianpour

An electromyographic investigation was conducted of finger and wrist muscle activity during typing. Examination of the data revealed substantial activity of the extrinsic extensor, a muscle which is ignored in many existing biomechanical finger models. This paper describes activity of the extensor muscle during typing, in absolute terms and relative to activity of the extrinsic flexors. Amplitude probability distribution analyses demonstrated that static extensor activity exceeded 5% MVC for all subjects. Two subjects exhibited pronounced patterns of coactivity in the extrinsic extensor and flexor muscles. Biomechanical modeling efforts demonstrated similar force contributions from the extrinsic extensors and flexors. Based on these results, neglect of finger extensor activity would result in underestimation of finger joint loading.


2002 ◽  
Vol 16 (2) ◽  
pp. 92-96
Author(s):  
Tiina Ritvanen ◽  
Reijo Koskelo ◽  
Osmo H„nninen

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.


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