With an accurate and powerful tennis kick serve, players can exploit any weaknesses in their opponents game and increase control by adding heavy topspin to the ball – making it harder for their opponent to return it.
Building an effective tennis kick serve requires using all available muscle groups – particularly those of the shoulder – efficiently; this process is known as force summation.
Stability
Kick serves involve the ball bouncing up off of the ground at an extreme angle with plenty of topspin, making it hard for an attacker to land an attack. But this topspin can be controlled depending on how high it’s thrown; additionally, it should not travel too far forward after impact; to achieve this, ensure your vertical projection speed matches up with intended ball height.
To establish an appropriate projection speed, we analyzed data collected from 12 right-handed high-performance male players who successfully delivered three full-swing (FS) and kick serves to a target area bordering their service box. This enabled us to gather reliable kinematics and 3-dimensional (3-D) joint kinetics data on every serve they delivered.
Results indicated that projection speed necessary to produce a high kick serve is determined primarily by the distance the racquet head travels after impact. A longer distance will produce lower projection speeds while shorter ones result in faster projection speeds. Furthermore, an optimal projection speed depends on both player height and serving force used to move the ball upward.
Key to the physics of an effective kick serve is producing enough spin. Unfortunately, many players struggle to generate enough topspin because their grip on the ball is insufficiently firm or they fail to generate sufficient angular velocity by not rotating their shoulders or elbows enough.
Kick serves can present many players with unique challenges; especially if they attempt to hit harder or faster than with their flat serve. When this occurs, their shoulder rotation opens too soon prior to impact and prevents them from producing enough topspin and twist. Furthermore, this is one reason many students cannot hit effective kick serves due to insufficient hip and shoulder rotation.
Acceleration
A tennis serve is typically executed with maximum power, skill and deception to gain the edge in a tennis point. This first stroke should aim either to win outright or place their receiver into an uncomfortable position for their next shot – this can be accomplished by hitting with topspin or by giving it a strong kick with topspin or both.
For top players to reach such fast serve speeds, they must accelerate the racquet rapidly through its contact phase. To accomplish this goal, energy must be stored in elastic tissues like tendons while simultaneously snapping forward faster than muscles can contract.
An important determining factor of these parameters is the angle at which the racquet head approaches the ball just prior to impact. In a typical kick serve, for instance, the racquet head approaches at 65 mph away and rises 5deg before impact. This produces approximately 780rpm of topspin which travels 6.3 or 8.4 meters (20.7 or 20.6 feet). Before it bounces back off again.
Acceleration of a racquet depends not only on arm and hand velocity but also body movement forward or backward in case of reverse swing, so maintaining good posture and alignment throughout contact phase is of utmost importance for success.
If the contact point is too far ahead or behind, it will be impossible to move in the desired direction at an important moment. Therefore, proper ball toss is of vital importance. Right-handed players should toss their balls slightly in front of themselves (for right-handers) while left-handeders should aim slightly further off to one side; this video shows an ideal ball toss for both slice and kick serves – this should be your goal when practicing your serves!
Contact
An effective tennis kick serve depends on transferring momentum from body to racket in an efficient and accurate fashion, which involves multiple components including body, arm, and racket. To understand their interactions, it’s necessary to learn some fundamental biomechanics principles.
Step one in understanding the biomechanics of a tennis kick serve is analyzing its body orientation at impact with the ball. Since a tennis serve relies on decelerating at impact for a split second so that arm acceleration can occur, optimal body positioning at contact maximizes leverage and height at contact – sideways is best!
At contact, it’s also important to consider where the shoulder is pointing: towards or away from the ball. Too often players rotate their shoulders too far back at contact and disrupt arm-hand rotation resulting in inaccurate ball placement or even misses entirely.
As your body nears contact, there are two schools of thought regarding toss technique. One group advocates throwing over your body – approximately 11 o’clock upon contact. According to these coaches, this style provides greater disguise for spin type detection by opponents while simultaneously relieving stress from wrist joints.
One school of thought suggests tossing closer to your dominant shoulder for maximum twist and spin action and faster serving speeds, although this requires additional hip and shoulder turn, which some players may find challenging to manage.
For an effective tennis kick serve, it is critical to maximize the power and accuracy of contact with the ball through proper stance, toss, knee bend, power position at contact and fast swing speed in order to take full advantage of spin generated by ball spin; this can be accomplished with proper wrist acceleration, which we will explore later in this series.
Spin
Kick serves that quickly rise above shoulder height require both topspin and high speed in order to be effective. Topspin can be created by swinging the racquet at an upward angle during groundstroke play; then when contact occurs between ball and racquet head during contact rotation causes spin along an axis that helps lift it into air. Topspin generation corresponds directly with how fast racquet head accelerates upon hitting ball (angular acceleration = tan A). The amount of topspin produced depends upon this formula: topspin is proportional to this acceleration (a = tan A) factor when the head hits ball (a = tan A).
Speed of approach of the racquet head to the ball and angle of approach are two primary elements that determine how much topspin is generated, although higher tosses and hitting with the head tilted forward can help generate even more spin (Fig. 11). The effects of these factors are demonstrated graphically in this figure.
Generating enough topspin for an effective kick serve presents several unique challenges, not the least of which being that the racquet head must remain at rest or nearly at rest during contact due to how high it’s thrown up into the air. Achieve this can be difficult without resorting to excessive stretching/strengthening programs or permitting players to develop back arches that exceed what can be maintained sustainably.
One challenge presented by high-speed serves is their steep angle of approach between racquet and ball, creating difficulty when trying to generate enough topspin. Some coaches advise their players to toss the ball further up front of them in order to generate more topspin.
Another element that can contribute to the amount of spin generated in a kick serve is how gravity acts upon its target; its force exerts a downward torque force that causes individual body segments to twist similarly as when subjected to twisting forces.