DIFFERENCES IN TENNIS SERVE KINEMATICS BETWEEN ELITE ADOLESCENT MALE AND FEMALE PLAYERS

The purpose of this study was to compare kinematic differences in elite adolescent male and female tennis serves. A 3D motion capture system was used to capture whole body, racquet and ball toss kinematics while twenty elite adolescent tennis players (male = 10, female = 10) performed flat and kick serves. Females had greater vertical front hip velocity (FS: 0.2 m/s, KS: 0.2 m/s greater than males), whilst males experienced larger peak shoulder external rotation displacements in both flat (10° greater) and kick (8° greater) serves compared to females. Females tossed the ball higher (FS: 18 cm, KS 19 cm) whilst males impacted the ball more laterally (across the body) (FS: 17cm, KS: 12) and more forward (FS: 10 cm, KS: 13 cm) into the court. Females had greater lower body kinematics whereas males tended to rely on shoulder external rotation to produce ball speed

IS THE KICK SERVE LINKED WITH PARS ABNORMALITIES IN ELITE ADOLESCENT TENNIS PLAYERS?

The purpose of this study was to compare lumbar kinetics in elite adolescent tennis players with and without pars abnormalities. A 3D motion capture system was used to capture lumbar spine kinetics while 24 right-handed elite adolescent tennis players (male = 14, female = 10, 9 players with pars abnormalities) performed kick serves. Players without pathology were found to have significantly greater peak lumbar posterior force (7.3 N/kg greater), left lateral flexion force (4 N/kg greater), right lateral flexion force (3.4 N/kg greater), flexion moment (2 Nm/kg greater) and left rotation moment (1.2 Nm/kg greater) during the drive phase. Interestingly, no differences were observed for peak kinetic values during the forward-swing phase. Those with pars abnormalities had lower lumbar loading overall compared with those without pars abnormalities

THE ACUTE EFFECTS OF A GRIP-CONSTRAINT TOOL ON UPPER BODY AND RACKET KINEMATICS DURING TENNIS FOREHANDS

The purpose of this study was to compare the acute effect of a grip-constraint tool on upper body and racket kinematics during tennis single-handed forehand strokes. Upper-body and racket kinematics for two grip conditions, Preferred (self-selected) and Grip-constraint tool (fixed semi-western forehand grip) were captured for eleven tennis players using a 22-camera Vicon motion capture system (240 Hz). Using a grip-constraint tool resulted in a more closed racket face tilt (~4°) at ball impact while having variations in joint rotations across the shoulder, elbow and wrist. This possibly demonstrates the participant’s ability to self-organise compensatory angular rotations across the upper limb to achieve similar impact orientations. Collectively, these data demonstrate the acute responses to modifying grip technique using a grip-constraint tool during single-handed down-the-line forehands

UPPER LIMB KINEMATICS DURING THE TOPSPIN DOUBLE-HANDED BACKHAND STROKE IN TENNIS

The purpose of this study was to compare non-dominant wrist kinematics during tennis double-handed backhand strokes in players using either an eastern or continental grip position. Trajectory data for two grips (eastern & continental) and depths (deep & short) were captured for sixteen sub-elite right-handed tennis players using a 12-camera Vicon motion capture system (250 Hz). The eastern grip demonstrated significantly faster horizontal racket head velocities compared to the continental grip. However, no differences were observed in accuracy or spin rate between grips (p \u3e 0.05). In the non-dominant upper limb for the continental condition, elbow flexion was smaller while wrist extension was larger throughout the swing. Collectively, these data suggest that the continental grip may place the wrist in a position that is more vulnerable to overuse injury

THE EFFECT OF GRIP POSITION ON UPPER LIMB ANGULAR KINEMATICS DURING TENNIS TOPSPIN DOUBLE-HANDED BACKHAND STROKES

The purpose of this study was to compare the effect of grip on upper limb angular kinematics of sub-elite tennis players during a topspin double-handed backhand while aiming crosscourt. Sixteen sub-elite right-handed tennis players performed double-handed backhand trials using two different non-dominant grips (eastern & continental). Upper limb trajectory data was captured using the Vicon motion capture system (250 Hz). Greater peak angular velocity was observed in the eastern grip at the dominant shoulder (flexion, extension, abduction, adduction) and non-dominant shoulder (extension), elbow (pronation) and wrist (flexion, ulna and radial deviation). Subsequently peak linear velocities for the racket head (horizontal), and upper limb resultant joint centres were greater in the eastern condition. Collectively, these data suggest that using the eastern grip in the non-dominant limb is more optimal for developing racket head speed, and may provide coaches relevant information for athlete development in double-handed backhands

MOVEMENT VARIABILITY IN ELBOW AND WRIST KINEMATICS OF NEW BALL OUTSWING BOWLING IN CRICKET FAST BOWLERS

This study investigated between-bowler movement variability of wrist and elbow kinematics during new ball swing bowling. A 3D motion analysis system captured the bowling action and ball trajectory of 11 pre-elite and elite fast bowlers delivering outswing. Kinematics were normalised to 100% of the delivery stride between back foot contact and ball release. A statistical parametric mapping approach using one-way ANOVAs investigated inter-individual movement variability. Significant differences were found in all kinematic parameters except for wrist radial/ulnar deviation angular velocity with bowlers using small amounts in either direction at the beginning of the phase. This study highlights that high-level athletic performance can be achieved using different movement variations and future research should include individual analyses of fast bowlers

ATLAS Run 1 searches for direct pair production of third-generation squarks at the Large Hadron Collider

This paper reviews and extends searches for the direct pair production of the scalar supersymmetric partners of the top and bottom quarks in proton-proton collisions collected by the ATLAS collaboration during the LHC Run 1. Most of the analyses use 20 fb$^{-1}$ of collisions at a centre-of-mass energy of $\sqrt{s}$ = 8 TeV, although in some case an additional 4.7 fb$^{-1}$ of collision data at $\sqrt{s}$ = 7 TeV are used. New analyses are introduced to improve the sensitivity to specific regions of the model parameter space. Since no evidence of third-generation squarks is found, exclusion limits are derived by combining several analyses and are presented in both a simplified model framework, assuming simple decay chains, as well as within the context of more elaborate phenomenological supersymmetric models.Comment: 53 pages plus author list + cover page (70 pages total), 24 figures, 10 tables, submitted to Eur. Phys. J., All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2014-07