caption: Objective During a serve, players bend their knees before making contact with the ball.
exif: {"Image DocumentName": "Objective During a serve, players bend their knees before making contact with the ball.", "Image ImageDescription": "How does knee flexion contribute to the overall velocity, power, force and energy delivered to the tennis ball Does knee flexion contribute to the rotational energy of the arm Or are they just isolated movements (i.e. knee flexion only contributes to force via linear momentum)", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}