Key factor, timing, tennis

7/30/2019 Key factor, timing, tennis

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J. Landlinger et al.

Journal of sports science and medicine (2010)9, 643-651


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Racquet speed is the players weapons intennis.

Inefficient motions and positions of variousjoints can either be detrimental to speed

and the spin of the ball or may increase the

risk of injury.


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There is no study comparing proximal-to

distal sequencing patterns of the

forehand with respect to elite vs. high

performance playing levels.


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To identify and compare key mechanical

features and their timing of forehand

groundstrokes between ATP-professionals(elite) and high performance (HP) youth

players when shots were played cross

court and down the line.


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ParticipantsAll male

Elite(Mean)

HighPerformance

(Mean)

Ranking ATP 347 Junior top 15

Age 23 16.3

Weight 78.2 72.8

Height 188.1 185.9


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Testing procedure:

Hit as many practice strokes as needed with the

same velocity and action as they would in the

match.

Use their own racquets.

Ball machine controlled pre-impact ball

horizontal velocity (20 m.s) and trajectory.


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2 series of 10 forehands cross court and

down the line (4 X 10 strokes) to a target

area (randomized order).

No instructions in terms of foot placement.

2 minutes break after each series.

6 fastest shots of each (= 12 strokes) wereused.


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Data Collection: 39 reflective markers were placed on bony

landmarks (Plug-in Gait Marker Set, Vicon

Peak, Oxford, UK).

4 markers (14 mm in diameter) were placed

on the racquet of each subject (racquet

head, shaft, at 3 and 9 oclock positions).

Participants wore tight shorts, no shirts.


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Data collection (cont.)

8 Vicon MX 13 cameras (Vicon Peak, Peak,

Oxford, UK) sampling at 400 Hz.

Cameras were positioned around one side of

the court;

3 behind the baseline

3 overhead cameras on a traverse at 4m height

in front of the player

The centre of baseline were used as theorigin of the global coordinate system.


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Data collection (cont.)

Y-axis

pointing forward to the net

X-axis positive to the right

Z-axis vertical

All 43 markers were reconstructed withthe Nexus software (Nexus 1.3, Vicon,

Oxford, UK), data were filtered with a

Woltring filter (MSE of 10).


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Data was analyzed during the forwardswing of the stroke.

Impact was the point where the firstball/racquet contact occurred.


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Descriptive statistics

Two-way ANOVA with repeated

measures


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Mean forward swing time of tennis forehanddid not vary between elite (0.324+ 0.086) andHP (0.326 + 0.064).

In the down the line situation, both groupsrotated their hips and racquets furtherbackwards (p


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The timing of peak angles help facilitate the

forward swing in the tennis forehand.

The hips must have started the counter-clockwise rotation towards the ball earlier than

the shoulders.Peak angular racquet rotation demonstrates

that the racquet tends to lag behind.

Extended wrist(55 milliseconds beforeimpact)should have put additional stretch onthe forearms to help generate wrist andracquet speed.


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To improve the forehand performance

level, the main 3 things to focus are;

Pelvis

Trunk rotation velocity

Their timing

A good rear leg drive will initiate pelvis

rotation, consequently, increase theseparation angle.
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Tanaporn Panich

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Key factor, timing, tennis

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