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.

The effect of spin level and ball exit speed on forearm muscle activity in the tennis forehand stroke

2021 ◽  
pp. 174795412110076
Author(s):  
Chantelle Rigozzi ◽  
Jeremy Cox ◽  
Gareth A Vio ◽  
William L Martens ◽  
Philip Poronnik
Keyword(s):  
Muscle Activity ◽  
Ball Speed ◽  
Tennis Players ◽  
Spin Level ◽  
Significant Difference ◽  
Exit Speed ◽  
Post Hoc ◽  
Lateral Elbow Tendinopathy ◽  
Extensor Carpi Radialis ◽  
Forearm Muscle

Elbow tendinopathy injuries are very common in tennis players. One of the commonly accepted theories describing the development of elbow tendinopathy in tennis is based on stiffness of the forearm skeletal muscle units and their repetitive overuse in the forehand stroke. Our objective was to use a novel microcontroller based wearable device to compare the influence of different forehand spin levels (flat, topspin and lob) and ball exit speed on forearm muscle activity in the potential onset of elbow tendinopathy in experienced adult tennis players. Peak normalised extensor carpi radialis (ECR) and flexor carpi radialis (FCR) muscle activity corresponding to each forehand shot and ball exit speed were determined and analysed. For the ECR shots (flat = 121, topspin = 272 and lob = 273) by 8 players, Kruskal-Wallis test (p < 0.001) and Post-Hoc tests revealed a significant difference between the flat and topspin spin levels (p < 0.01) and flat and lob spin levels (p < 0.001). For the FCR shots (flat = 125, topspin = 301 and lob = 303) by 9 players, Kruskal-Wallis test showed no significant difference between the three spin levels. For the corresponding ball speed, the Kruskal-Wallis (p < 0.001) and subsequent Post-Hoc (p < 0.001) showed that flat hits had the significantly highest ball speed followed by topspin then lob accordingly for both muscles included shots. Our results suggest that coaches could consider recommending players to hit forehands with topspin in order to potentially reduce the risk of developing lateral elbow tendinopathy.

Trunk and Upper Limb Muscle Activation During Flat and Topspin Forehand Drives in Young Tennis Players

2011 ◽  
Vol 27 (1) ◽  
pp. 15-21 ◽  
Author(s):  
Isabelle Rogowski ◽  
David Rouffet ◽  
Frédéric Lambalot ◽  
Olivier Brosseau ◽  
Christophe Hautier
Keyword(s):  
Upper Limb ◽  
Vertical Velocity ◽  
Muscle Activity ◽  
Muscle Activation ◽  
Emg Activity ◽  
Shoulder Abduction ◽  
Joint Angles ◽  
Tennis Players ◽  
Shoulder Muscle ◽  
Forearm Muscle

This study compared EMG activity of young tennis players’ muscles during forehand drives in two groups, GD—those able to raise by more than 150% the vertical velocity of racket-face at impact from flat to topspin forehand drives, and GND, those not able to increase their vertical velocity to the same extent. Upper limb joint angles, racket-face velocities, and average EMGrms values, were studied. At similar joint angles, a fall in horizontal velocity and a rise in racket-face vertical velocity from flat to topspin forehand drives were observed. Shoulder muscle activity rose from flat to topspin forehand drives in GND, but not for drives in GD. Forearm muscle activity reduced from flat to topspin forehand drives in GD, but muscle activation was similar in GND. The results show that radial deviation increased racket-face vertical velocity more at impact from the flat to topspin forehand drives than shoulder abduction.

Alternative to Reduced Stresses on the Upper Extremity in a Standing Workstation

2021 ◽  
pp. 001872082110573
Author(s):  
Ilseok Lee ◽  
Jiwon Choi ◽  
Sang Hyeon Kang ◽  
Sangeun Jin
Keyword(s):  
Muscle Activation ◽  
Elbow Flexion ◽  
Upper Body ◽  
Wrist Extension ◽  
Activation Level ◽  
Anterior Deltoid ◽  
The Many ◽  
The Cost ◽  
Extensor Carpi Radialis ◽  
Forearm Muscle

Objective This study evaluated a standing armrest to provide more acceptable ergonomic guidelines that may reduce the cost of standing computer workstations. Background Of the many advantages of standing workstations, there have been no efforts to minimize the biomechanical cost, such as larger wrist extension and greater forearm muscle activity than sitting. Method Sixteen participants were asked to perform a typing task under a combination of the following factors: (1) desk shape (rectangular and concave); (2) desk height (0, +5, -5 cm from 90° elbow flexion); and (3) monitor height (0, −10 cm from the eyes). During the trials, the trunk kinematics, muscle activation levels, and CoP were recorded. Results Both arms were further away from the upper body under the concave and +5 desk height than under the normal condition, but significant decreases in the extensor carpi radialis (8.6%), anterior deltoid (28.8%), and L4 paraspinals (5.5%) were observed. Similarly, the wrist extension angle decreased by 10.5° (42%) under this condition, but the posture required a 2.2° (19%) increase in wrist adduction angle. The CoP irregularity was greater under the concave workstation, indicating more complex motion. Conclusion A higher and concave desk can provide an armrest effect while engaged in a standing workstation by reducing the wrist extension and related muscle activation level, but at the cost of a larger wrist adduction angle. Application Providing a standing armrest (+5 cm height and concave desk) could reduce the stresses on the upper extremities, but a split keyboard should be considered to minimize wrist adduction.

Older Adults Use a Unique Strategy to Lift Inertial Loads With the Elbow Flexor Muscles

2000 ◽  
Vol 83 (4) ◽  
pp. 2030-2039 ◽  
Author(s):  
Andrew E. Graves ◽  
Kurt W. Kornatz ◽  
Roger M. Enoka
Keyword(s):  
Young Adults ◽  
Elbow Joint ◽  
Muscle Activation ◽  
Angular Displacement ◽  
Elbow Flexor ◽  
Lengthening Contractions ◽  
Old Adults ◽  
Flexor Muscles ◽  
Elbow Flexor Muscles ◽  
Target Force

The purpose of this study was to determine the effect of age on the ability to exert steady forces and to perform steady flexion movements with the muscles that cross the elbow joint. An isometric task required subjects to exert a steady force to match a target force that was displayed on a monitor. An anisometric task required subjects to raise and lower inertial loads so that the angular displacement around the elbow joint matched a template displayed on a monitor. Steadiness was measured as the coefficient of variation of force and as the normalized standard deviation of wrist acceleration. For the isometric task, steadiness as a function of target force decreased similarly for old adults and young adults. For the anisometric task, steadiness increased as a function of the inertial load and there were significant differences caused by age. Old adults were less steady than young adults during both shortening and lengthening contractions with the lightest loads. Furthermore, old adults were least steady when performing lengthening contractions. These behaviors appear to be associated with the patterns of muscle activation. These results suggest that different neural strategies are used to control isometric and anisometric contractions performed with the elbow flexor muscles and that these strategies do not change in parallel with advancing age.

scholarly journals Can Whole-Body Vibration Exercises in Different Positions Change Muscular Activity of Upper Limbs? A Randomized Trial

Dose-Response ◽  
2018 ◽  
Vol 16 (4) ◽  
pp. 155932581880436 ◽  
Author(s):  
Danielle S Morel ◽  
Pedro J Marín ◽  
Eloá Moreira-Marconi ◽  
Carla F Dionello ◽  
Mario Bernardo-Filho
Keyword(s):  
Muscle Activation ◽  
Handgrip Strength ◽  
Whole Body Vibration ◽  
Muscular Activity ◽  
Whole Body ◽  
Acute Effects ◽  
Body Vibration ◽  
Test Sets ◽  
Flexor Digitorum ◽  
Push Up

The aim of this study was to investigate the acute effects of whole-body vibration exercises (WBVE) in different positions on muscular activity of flexor digitorum superficialis (FD), wrist extensor (ED), and handgrip strength (HG) of healthy men. Fifteen participants have performed 5 test sets each one consisting of HG strength measurement and 1-minute WBVE intervention (frequency: 50 Hz, amplitude: 1.53 mm, synchronous tri-planar oscillating/vibratory platform), that could be control (no exposition to vibration), squat (30 seconds of rest and 30 seconds of WBVE in squat position), or push-up (30 seconds of rest, and 30 seconds of WBVE in push-up position). After testing, participants had 2 minutes of rest and then were encouraged to keep themselves on a pull-up bar for 30 seconds. During all procedures, muscular activity of FD and ED was measured by surface electromyography (EMG). Statistical analysis has revealed that the EMG measured in the FD during the static pull-up bar exercise after SQUAT condition was significantly higher ( P = .004) than the CONTROL and PUSH-UP conditions. Whole-body vibration exercises in squat position increase acutely muscle activation of the FD during isometric exercises of longer duration, while muscle activation of ED and HG strength are not affected by WBVE.

scholarly journals Hindlimb muscular activity, kinetics and kinematics of cats jumping to their maximum achievable heights

1981 ◽  
Vol 91 (1) ◽  
pp. 73-86 ◽  
Author(s):  
F. E. Zajac ◽  
M. R. Zomlefer ◽  
W. S. Levine
Keyword(s):  
Vertical Jump ◽  
Muscular Activity ◽  
Dynamic State ◽  
Extensor Muscles ◽  
Ankle Joints ◽  
Flexor Muscles ◽  
Reaction Forces ◽  
Vertical Ground ◽  
Vertical Ground Reaction Forces ◽  
Propulsion Phase

Cats were trained to jump from a force platform to their maximum achievable heights. Vertical ground reaction forces developed by individual hindlimbs showed that the propulsion phase consists of two epochs. During the initial “preparatory phase' the cat can traverse many different paths. Irrespective of the path traversed, however, the cat always attains the same position, velocity and momentum at the end of this phase. Starting from this dynamic state the cat during the subsequent “launching phase' (about 150 ms long) generates significant propulsion as its hindlimbs develop force with identical, stereotypic profiles. Cinematographic data, electromyographic data, and computed torques about the hip, knee and ankle joints indicate that during the jump proximal extensor musculature is activated before distal musculature. During terminal experiments when the hindlimb was set at positions corresponding to those in the jump, isometric torques produced by tetanic stimulation of groups of extensor and flexor muscles were compared with computed torques developed by the same cat during previous jumps. These comparisons suggest that extensor muscles of the hindlimb are fully activated during the maximal vertical jump.

Quantification of forearm muscle activation by ultrasound imaging and high-density electromyography

2021 ◽  
Vol 150 (4) ◽  
pp. A289-A289
Author(s):  
Zhiyu Sheng ◽  
Ernesto Bedoy ◽  
Douglas J. Weber ◽  
Brad E. Dicianno ◽  
Kang Kim
Keyword(s):  
Ultrasound Imaging ◽  
Muscle Activation ◽  
High Density ◽  
Forearm Muscle

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.

Forearm muscle profiles in tennis players

2005 ◽  
Vol 13 (2) ◽  
pp. 147-151 ◽  
Author(s):  
J.C. Fleming ◽  
A.H. McGregor
Keyword(s):  
Tennis Players ◽  
Forearm Muscle

Extracting and Classifying Spatial Muscle Activation Patterns in Forearm Flexor Muscles Using High-Density Electromyogram Recordings

2019 ◽  
Vol 29 (01) ◽  
pp. 1850025 ◽  
Author(s):  
Chenyun Dai ◽  
Xiaogang Hu
Keyword(s):  
Pattern Recognition ◽  
Spatial Patterns ◽  
Muscle Activation ◽  
High Density ◽  
Emg Activity ◽  
Finger Movement ◽  
Activation Patterns ◽  
Flexor Muscles ◽  
Forearm Flexor Muscles ◽  
Forearm Flexor

The human hand is capable of producing versatile yet precise movements largely owing to the complex neuromuscular systems that control our finger movement. This study seeks to quantify the spatial activation patterns of the forearm flexor muscles during individualized finger flexions. High-density (HD) surface electromyogram (sEMG) signals of forearm flexor muscles were obtained, and individual motor units were decomposed from the sEMG. Both macro-level spatial patterns of EMG activity and micro-level motor unit distributions were used to systematically characterize the forearm flexor activation patterns. Different features capturing the spatial patterns were extracted, and the unique patterns of forearm flexor activation were then quantified using pattern recognition approaches. We found that the forearm flexor spatial activation during the ring finger flexion was mostly distinct from other fingers, whereas the activation patterns of the middle finger were least distinguishable. However, all the different activation patterns can still be classified in high accuracy (94–100%) using pattern recognition. Our findings indicate that the partial overlapping of neural activation can limit accurate identification of specific finger movement based on limited recordings and sEMG features, and that HD sEMG recordings capturing detailed spatial activation patterns at both macro- and micro-levels are needed.

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