How to hit flat, slice and kick serves

One swing, three balls. Tilt the axis and the bounce changes.

Traced from real footage

See it, eight instants at a time.

Every frame is traced from real match footage, so you see the shape of the stroke, not a drawing of an idea.

Kyrgios's serve, instant 1 of 8 — Kyrgios's serve: eight instants traced from the footage, frame for frame. Hover or tap to flip.

Kyrgios's serve: eight instants traced from the footage, frame for frame. Hover or tap to flip.

Key facts

1
A kick serve's spin axis sits about 10–30° off vertical, so it's mostly sidespin, with total spin of 3,200–4,500 rpm.
Tennis Warehouse University, Physics of the Tennis Kick Serve
2
At contact on a kick serve the racquet rises only about 5°, against about 30° for a topspin groundstroke.
Tennis Warehouse University, Physics of the Tennis Kick Serve
3
A kick serve crosses the baseline at 5–6 ft.
Tennis Warehouse University, Physics of the Tennis Kick Serve
4
After the bounce the court supplies the upward rebound while the topspin force keeps pulling the ball down, so "more topspin means a higher bounce" isn't a safe rule.
Cross, The kick serve in tennis

Why it works

Spin is the Magnus force with a direction. The topspin part pushes the ball down, so you can clear the net by more and still land it. The sidespin part curves it. Tilting the spin axis is how one swing makes three different balls.

After the bounce the court supplies the upward rebound, and the spin force keeps pulling down during the next flight. What happened before contact helped set the rebound, and the forces after it keep changing the path. That's the kick-serve paradox: a ball that pulls down still jumps up.

Nothing else about the motion needs to change: contact stays at the top of your reach with the arm straight. Only the racquet's path through the ball changes, and that's the disguise.

The line to say on court
“Same swing. Different clock hand.”

Drill: The clock

12 min · alone

Put a marker on the back fence at your shoulder height and take a basket of balls.
Hit ten flat serves to the deuce T, brushing from 6 to 12.
Hit ten slice serves to the deuce wide corner, brushing around the outside of the ball.
Hit ten kick serves to the ad backhand corner, brushing from 7 to 1. Count the bounces that pass the marker.

Number to beat6 of 10 kick serves bouncing above the shoulder marker

More drills like this: serve, practise alone

Faults and fixes

Kick tossed in front

Without an arch, the brush can't go up and across.

FixToss over your head.

Pancake face on the flat serve

Turning the face early kills the turn through the ball.

FixDrop the racquet edge-on and turn late.

Slice from the wrist

You twist the face instead of brushing the outside.

FixBrush around the ball with the arm and keep the face quiet.

Kick hit at full pace

Speed steals brush, so the ball skids instead of climbing.

FixUse a slower arm and a faster brush. The fence marker keeps you honest.

Questions players ask

Which second serve should I hit to a right-hander's backhand from the ad court?

Usually the kick. It climbs into the backhand shoulder they don't want it on. A right-hander's slice wide from the ad side tends to curve toward their forehand, and a flat serve has the lowest margin.

Is a kick serve topspin?

Mostly sidespin. Its axis sits about 10–30° off vertical, with a topspin part that pulls it down over the net.

Why does my kick serve skid instead of jumping?

You're probably hitting it at full pace, and speed steals brush. Use a slower arm and a faster brush.

How do you disguise your serve?

Keep the motion the same and change only where the strings brush the ball: 6 to 12, around the outside, or 7 to 1.

What this doesn't cover

The spin and bounce numbers here are for the kick serve only. Reliable ranges for flat and slice spin, their bounce heights and kick serve speeds still need sourcing. Ball-flight model heights are illustrations, not predictions for any serve, and spin can't be read from ordinary video. Placement advice assumes a right-handed server.

Sources

Tennis Warehouse University, Physics of the Tennis Kick Serve
Cross, The kick serve in tennis

Serve and returnHow to toss the ball for a tennis serveToss from a straight, locked arm, release at eye level, and send the ball to the same spot every time. For a right-hander, the flat serve's toss sits slightly in front and to the right, slice further right, kick further over the head. The toss sets contact height, spin and placement before you swing, so fix a wobbly serve at the hand first.Serve and returnHow to hit a reliable second serve under pressureHit your second serve with the same swing as your first, more brush and one proven target. Slowing the arm to be safe removes the spin that gives you net clearance, so you get a slower ball with less clearance and a returner stepping in. Top-50 men win about 57.5 % of second-serve points, against 73.6 % behind a first.Serve and returnHow to serve in tennis: the service motion step by stepA good tennis serve is a throw that starts in your legs, passes through your trunk and shoulder, and reaches the racquet last. Legs and trunk supply about 51–55 % of the serve's kinetic energy, and shoulder internal rotation about 40 % of racquet-head speed. Load the knees, let the racquet drop edge-on, reach up to a straight-arm contact and land inside the baseline.StrikeHow topspin works: the Magnus effect in tennisTopspin works through the Magnus effect: a spinning ball drags air around with it, and the pressure difference pushes the ball at right angles to its spin axis. With topspin that push points down, so the ball dives. At heavy pro topspin the push is about 0.5 N, close to the ball's own 0.56 N weight. That lets you aim high, swing hard and still land it.