New Pistol Grip Control for an Electric Utility Aerial Bucket Reduces Risk of Forearm Muscle Fatigue

2018 ◽  
Vol 62 (1) ◽  
pp. 888-892
Author(s):  
Richard W. Marklin ◽  
Jonathon E. Slightam ◽  
Mark L. Nagurka ◽  
Casey D. Garces ◽  
Lovely Krishen ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Muscular Activity ◽  
Electric Utility ◽  
Scale Model ◽  
Overhead Line ◽  
Endurance Time ◽  
Forearm Muscles ◽  
Actual Equipment ◽  
Forearm Muscle ◽  
Semg Activity

Overhead line workers have anecdotally reported elevated levels of fatigue in forearm muscles when operating the pistol grip control that maneuvers an aerial bucket on a utility truck. Previous research with surface electromyographic (sEMG) recordings of forearm muscles corroborated these reports of muscle fatigue. A new pistol grip was designed that reduces the applied force by 50% in all directions of movement. In laboratory testing, sEMG signals were recorded from the upper extremity muscles of twenty subjects, who operated a conventional-force pistol grip and the 50% reduced-force control to move a 1/15 scale model of an aerial truck boom. The muscle that resulted in the greatest sEMG activity (extensor digitorum communis (EDC)) was the muscle that workers typically pointed to when they reported forearm muscle fatigue from using the control. The reduced-forced pistol grip decreased EDC sEMG by an average of 5.6%, compared to the conventional control, increasing the maximum endurance time by 38% according to muscle fatigue models. This study was the first to quantify muscular activity of a new aerial bucket pistol grip control and the results show promise for improving the occupational health of electric utility overhead line workers, specifically reducing muscle fatigue. Before the new design of the pistol grip can be commercialized, it must be tested in the field on actual equipment.

scholarly journals Applied Force and sEMG Muscle Activity Required To Operate Pistol Grip Control in an Electric Utility Aerial Bucket

2017 ◽  
Vol 61 (1) ◽  
pp. 963-967 ◽  
Author(s):  
Richard W. Marklin ◽  
Jonathon E. Slightam ◽  
Mark L. Nagurka ◽  
Trent M. Wolff ◽  
Casey D. Garces ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Electric Utility ◽  
Applied Force ◽  
The Other ◽  
Flexor Digitorum Superficialis ◽  
Overhead Line ◽  
Flexor Digitorum ◽  
Forearm Muscle ◽  
Semg Activity ◽  
Semg Signals

Electric utility line workers report high levels of fatigue in forearm muscles when operating a conventional pistol grip control in aerial buckets. This study measured the applied force and surface electromyographic (sEMG) signals from four upper extremity muscles required to operate the pistol grip control in two tasks. The first task was movement of the pistol grip in six directions (up/down, forward/rearward, clockwise/counter-clockwise), and the second task was movement of the bucket from its resting position on the truck bed to an overhead conductor on top of a 40 ft tall pole. The force applied to the pistol grip was measured in 14 aerial bucket trucks, and sEMG activity was measured on eight apprentice line workers. The applied force required to move the pistol grip control in the six directions ranged from 12 to 15 lb. The sEMG activity in the extensor digitorum communis (EDC) forearm muscle was approximately twice as great or more than the other three muscles (flexor digitorum superficialis, triceps, and biceps). Line workers exerted 14 to 30% MVCEMG to move the pistol grip in the six directions. Average %MVCEMG of the EDC to move the bucket from the truck platform to an overhead line ranged from 26 to 30% across the four phases of the task. The sEMG findings from this study provide physiologic evidence to support the anecdotal reports of muscle fatigue from line workers after using the pistol grip control for repeated, long durations.

scholarly journals Influence of Ball Impact Location on Racquet Kinematics, Forearm Muscle Activation and Shot Accuracy during the Forehand Groundstrokes in Tennis

Proceedings ◽  
2020 ◽  
Vol 49 (1) ◽  
pp. 89
Author(s):  
Masahiro Ikenaga ◽  
Nobue Okuma ◽  
Hiroki Nishiyama ◽  
Shinichiro Chiba ◽  
Katsutoshi Nishino ◽  
...  
Keyword(s):  
Muscle Activation ◽  
Muscular Activity ◽  
Side Impact ◽  
Ball Impact ◽  
Tennis Players ◽  
Impact Location ◽  
Flexor Muscles ◽  
Flight Parameters ◽  
Extensor Carpi Radialis ◽  
Forearm Muscle

We aimed to clarify the effect of ball–racquet impact locations on the dynamic behavior of tennis racquet, the accuracy of shots and muscle activation of the forearm. Eight male intermediate tennis players performed ten forehand groundstrokes. A motion capture system was used to measure the motions of racquet, ball and human body at 2000 Hz, and electromyography (EMG) activities of wrist extensor and flexor muscles were measured simultaneously. The flight parameters of the ball were measured by ballistic measurement equipment. All shots were divided into tertiles based on ball impact location along the lateral axis of tennis racquet. We found that the off-center, upper-side impact induces a larger muscular activity in extensor carpi radialis. Passive radial deviation of the wrist occurring immediately after ball impact may account for this. Furthermore, the off-center, upper-side impact could be associated with a missed shot having a lower, outward ball launch angle.

sEMG feature analysis on forearm muscle fatigue during isometric contractions

2014 ◽  
Vol 20 (2) ◽  
pp. 139-143 ◽  
Author(s):  
Dong Ming ◽  
Xin Wang ◽  
Rui Xu ◽  
Shuang Qiu ◽  
Xin Zhao ◽  
...  
Keyword(s):  
Muscle Fatigue ◽  
Feature Analysis ◽  
Isometric Contractions ◽  
Forearm Muscle

Effects of Handle Angle and Work Orientation on Hammering: II. Muscle Fatigue and Subjective Ratings of Body Discomfort

1989 ◽  
Vol 31 (4) ◽  
pp. 413-420 ◽  
Author(s):  
Richard W. Schoenmarklin ◽  
William S. Marras
Keyword(s):  
Muscle Fatigue ◽  
Work Orientation ◽  
Subjective Ratings ◽  
Ulnar Deviation ◽  
Companion Article ◽  
Body Discomfort ◽  
Forearm Muscle

This research investigated how changes in hammer handle angle and hammering orientation affected muscle fatigue in the forearm and subjective ratings of body discomfort. Forearm muscle fatigue and discomfort ratings were not significantly affected by handle angle, but they were significantly higher in the wall hammering orientation than in the bench orientation. The research in this article and in the companion article (Part I) reveal that for novices, hammers with handles angled in the range of 20-40 deg are advantageous because (1) they reduce ulnar deviation and may possibly decrease the incidence of hand/wrist disorders, and (2) they do not significantly affect hammering performance in the bench conditions, forearm muscle fatigue, or subjective ratings of body discomfort.

Effects of String Stiffness on Muscle Fatigue After a Simulated Tennis Match

2014 ◽  
Vol 30 (3) ◽  
pp. 401-406 ◽  
Author(s):  
Jean Bernard Fabre ◽  
Vincent Martin ◽  
Gil Borelli ◽  
Jean Theurel ◽  
Laurent Grélot
Keyword(s):  
Resonant Frequency ◽  
Muscle Fatigue ◽  
Ball Speed ◽  
Tennis Players ◽  
High Stiffness ◽  
Fatigue Development ◽  
Low Stiffness ◽  
Exercise Muscle ◽  
Forearm Muscle ◽  
Tennis Match

We tested the influence of string stiffness on the occurrence of forearm muscle fatigue during a tennis match. Sixteen tennis players performed two prolonged simulated tennis matches with low-stiffness or high-stiffness string. Before and immediately after exercise, muscle fatigability was evaluated on the forearm muscles during a maximal intermittent gripping task. Groundstroke ball speeds and the profile of acceleration of the racquet frame at collision were recorded during each match. The peak-to-peak amplitude of acceleration and the resonant frequency of the frame were significantly greater with high- (5060 ± 1892 m/s2and 204 ± 29 Hz, respectively) than with low-stiffness string (4704 ± 1671 m/s2and 191 ± 16 Hz, respectively). The maximal and the averaged gripping forces developed during the gripping task were significantly reduced after the tennis match with high- (−15 ± 14%, and −22 ± 14%, respectively), but not with low-stiffness string. The decrease of ball speed during the simulated matches tended to be greater with high- than with low-stiffness string (P= .06). Hence, playing tennis with high-stiffness string promotes forearm muscle fatigue development, which could partly contribute to the groundstroke ball speed decrement during the game.

scholarly journals Relationship between Occlusal Force Distribution and the Activity of Masseter and Anterior Temporalis Muscles in Asymptomatic Young Adults

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Aneta Wieczorek ◽  
Jolanta Loster ◽  
Bartlomiej W. Loster
Keyword(s):  
Young Adults ◽  
Temporomandibular Disorder ◽  
Muscular Activity ◽  
Surface Emg ◽  
Occlusal Contact ◽  
Contact Points ◽  
Study Population ◽  
The Relationship ◽  
Semg Activity ◽  
Anterior Temporalis

Healthy subjects have a prevalent side on which they display higher-muscle activity during clenching. The relationship between symmetry of masseter muscle (MM) and anterior temporalis (TA) muscle activities and occlusion has been evaluated on the basis of physiological parameters. The aim of the present study was to investigate whether the symmetry of surface EMG (sEMG) activity in asymptomatic young adults is related to symmetry of occlusal contacts.Material. The study population consisted of seventy-two 18-year-old subjects with no temporomandibular disorder (TMD) symptoms.Method. All the participants underwent an sEMG recording with an 8-channel electromyograph (BioEMG III). A T-Scan III evolution 7.01 device was used to analyze the occlusal contact points.Results. The correlation between the activity of right (R) and left (L) TA and the percentage of occlusal contacts was assessed, but no significant differences were found between the RMM and LMM muscles. The differences in the medium values of sEMG between males and females were not statistically significant. Equilibrated muscular activity between RTA and LTA occurred when occlusal contacts reached the percentage of 65% on the left side.Conclusion. The symmetry of sEMG activity in asymptomatic young adults is not related to symmetry of occlusal contacts.

Implementation of an efficient muscle fatigue model in the framework of multibody systems dynamics for analysis of human movements

2011 ◽  
Vol 225 (4) ◽  
pp. 359-370 ◽  
Author(s):  
A F Pereira ◽  
M T Silva ◽  
J M Martins ◽  
M de Carvalho
Keyword(s):  
Muscle Fatigue ◽  
Equations Of Motion ◽  
Motor Units ◽  
Systems Dynamics ◽  
Main Body ◽  
Endurance Time ◽  
Human Movements ◽  
Fatigue Model ◽  
Body Joints ◽  
Muscle Actuators

The aim of this study is to implement and integrate a novel and versatile muscle fatigue model in an existing multibody formulation with natural coordinates. The equations of motion of the formulation are rearranged to deal with muscle actuators as externally concentrated forces instead of being considered as kinematic muscle actuator drivers. A muscle fatigue model, originally developed to predict the endurance time of the main body joints, is included in the multibody formulation. The model stems from the compartment theory and uses a bounded controller to rule the rate of motor units changing between the three compartments (resting, activated, and fatigued) that made up the model. The resulting formulation is applied to two example cases involving the human upper extremity, with redundant muscles, to evaluate its robustness and accuracy. Results showed that the proposed methodologies are a valid approach for the calculation of the redundant muscle forces in the presence of muscular fatigue.

Effects of vibratory massage therapy on grip strength, endurance time and forearm muscle performance

Work ◽  
2021 ◽  
Vol 68 (3) ◽  
pp. 619-632
Author(s):  
Mohd Mukhtar Alam ◽  
Abid Ali Khan ◽  
Mohd Farooq
Keyword(s):  
Grip Strength ◽  
Pearson Correlation ◽  
Massage Therapy ◽  
Voluntary Contraction ◽  
Muscle Performance ◽  
Emg Activity ◽  
Endurance Time ◽  
Vibration Therapy ◽  
Forearm Muscle ◽  
Grip Endurance

BACKGROUND: Vibration therapy (VT) causes an increase in motor unit activation tendency, an involuntary recruitment of earlier sedentary motor units, which increases the muscle fiber force generating capacity and muscle performance. OBJECTIVE: To evaluate the effect of vibratory massage therapy at 23 Hz and 35 Hz on grip strength, endurance, and forearm muscle performance (in terms of EMG activity). METHODS: Ten healthy and right-handed men participated voluntarily in this study. The experiment was characterized by the measurement of MVC (maximal voluntary contraction) grip strength and grip endurance time at 50%MVC, accompanied by the corresponding measurement of the EMG signals of the muscles viz., flexor digitorum superficialis (FDS); flexor carpi ulnaris (FCU); extensor carpi radialis brevis (ECRB); and extensor carpi ulnaris (ECU) in supine posture. RESULTS: MANCOVA results showed significant effects of VT frequency on endurance time (p < 0.001); but no significant effect on the grip strength (p = 0.161) and muscle performance (in terms of EMG activities of the forearm muscles). However, VT improves the MVC grip strength and grip endurance time (better at 35 Hz). The Pearson correlation was significant between: weight, palm length, palm circumference, and forearm length with MVC grip strength; and the palm length with the endurance time. In addition, the palm length, palm circumference, and forearm circumference generally serve to better predict MVC grip strength and grip endurance time. CONCLUSIONS: Vibration therapy at 35 Hz for 10 minutes on the forearms had a significant positive effect on the neuromuscular performance to enhance muscle performance of upper extermitites and can be used as the optimal range to study the effect of VT. Findings may be used to prepare guidelines for VT in rehabilitation, healthcare, sports, and medical for therapists.

Sign in / Sign up

Export Citation Format

Share Document