How to hit harder in tennis without swinging harder

Hit harder without swinging harder.

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.

Sinner's forehand, instant 5 of 8 — Sinner's forehand: eight instants traced from the footage, frame for frame. Hover or tap to flip; the dot marks contact.

Sinner's forehand: eight instants traced from the footage, frame for frame. Hover or tap to flip; the dot marks contact.

Try it

Move the idea yourself.

One instrument from The Program, free here. Drag it and watch the numbers change: models are labelled as models.

The chain · serve

Model

Traced serve · 6/8

Through the servecontact

100 %

racquet speed at contact, relative

Each link peaks just after the one below it and passes the speed up. The racquet, last, gets the sum. The figure is a traced tour serve; the curves are drawn for illustration. Legs, hips and trunk: about 51 % of the energy (Kibler 1995). Of the arm's share of racquet speed: internal rotation about 40 %, pronation about 5 % (Elliott 2006).

Key facts

~40%
On the serve, internal rotation of the shoulder is the biggest single contributor to racquet speed, about 40%.
Elliott, "Biomechanics and tennis", British Journal of Sports Medicine, 2006
15%
Elliott’s Table 2 estimates upper-arm horizontal flexion at 15% for the power serve and 25% for forward racquet velocity in the topspin forehand.
Elliott, 2006, Table 2
48.1%
Pedro and colleagues found upper-arm flexion/abduction contributions of 48.1% cross-court and 45.2% inside-out in six players performing attacking forehands. The direction difference was not statistically significant.
Pedro et al., Sensors, 2022, Table 2; forward racquet-head centre velocity at impact
45.43m/s
A preliminary study of four ranked players reports peak racquet velocities during acceleration of 34.89 and 45.43 m/s for its slow-versus-fast serve comparison. These are racquet speeds, not ball speeds or population norms.
Gorce & Jacquier-Bret, Frontiers, 2024
51–55%
The 51–55% estimate concerns energy delivered to the hand by the legs and trunk together during the serve. It cannot be added to a percentage of racquet velocity.
Kovacs & Ellenbecker, Sports Health, 2011

Why it works

The court exerts an equal and opposite force when the player pushes against it. Muscle work and coordinated movement throughout the body also contribute to the stroke.

Legs, trunk, arm and racquet interact. A proximal-to-distal sequence is a learning cue, not a requirement that five measured speed peaks occur in a fixed order.

The lesson’s video-derived poses are smoothed and retimed. Their speed scale, ball speed and spin were presentation values. Relative motion is displayed; calibrated speed, energy and activation timing are not measured by these curves.

The line to say on court
“The arm is last.”

Drill: The chain count

15 min · alone

Shadow-swing 20 forehands, counting out loud: legs, hips, torso, arm, racquet.
Drop-feed 20 forehands from a comfortable knee bend and easy turn. Coordinate the legs, trunk and arm.
Count how many land past the service line without you trying harder.

Number to beat12 of 20 balls past the service line at comfortable effort

More drills like this: forehand

Faults and fixes

Arming the ball

Limited leg and trunk involvement can leave more of the task to the arm.

FixUse a comfortable knee bend and an easy unit turn. Compare similar drop-feeds.

Early arm firing

The arm may be poorly coordinated with the trunk for this stroke.

FixRhythm and shadow-stroke drills, counting the sequence out loud: legs, hips, torso, arm, racquet.

Poor separation

The pelvis and shoulders may move together more than intended for this stroke.

FixTry a slow shadow turn; explore resistance and range with a coach.

Off-balance base

An unstable base can make the intended stroke harder to coordinate.

FixFootwork and stance work: land balanced, load evenly, keep the base under the shot.

Blocked deceleration

An abruptly constrained swing may disrupt comfortable acceleration and deceleration.

FixUse a comfortable finish and review contact and spacing as well as timing.

Questions players ask

Does tennis power come from the arm?

The arm contributes actively alongside the legs and trunk. Upper-arm internal rotation is an important contributor to racquet velocity at serve impact.

What is the kinetic chain in tennis?

The linked body segments that coordinate movement and transfer energy during the stroke.

Which part of the body is fastest at contact?

The racquet head can move much faster than the body’s joint centres. That comparison does not establish which segment supplied the most energy.

Do the links have to fire in a strict order?

A body-to-racquet sequence is a coaching cue. Exact timing varies with the stroke and player; these retimed, two-dimensional curves cannot verify a fixed order of five speed peaks.

What this doesn't cover

The Wave uses one retimed forehand reconstruction and a relative movement display. It cannot verify absolute speed, spin, energy transfer or a strict sequence of measured peaks. The alternate comparison makes two independent chart edits: an earlier arm curve and a reduced racquet curve. The reduction is assigned, not a calculated consequence. The 2024 study used optical markers and four ranked players, not wearable sensors on a professional sample. Serve estimates do not measure this forehand. Contribution percentages depend on the study, stroke and velocity definition; the serve estimates are not a pooled range. The 2022 forehand study used six elite men and 120 Hz inertial sensors in an attacking task.

Sources

StrikeHow to use hip and shoulder separation for a heavier forehandFor a heavier forehand, coil the shoulders against the hips on the unit turn, then fire the hips first while the shoulders hold for a beat. That stretches the trunk like a spring, and the shoulders uncoil on top of the hips' speed. A longer backswing isn't a speed source. The coil is.StrikeHow to use your legs on the tennis serveTo use your legs on the serve, bend into a deep load and push the court away, then leave the ground and land on your front foot inside the baseline. The court pushes back with the same force, and that force is the budget your hips, trunk and arm spend. Elite servers push about 1.5 to 2.1 times their body weight into the ground.StrikeHow to get racquet lag on your forehandYou get racquet lag on your forehand by keeping your hand soft while your body turns, so the racquet head trails your hand and then releases. Don't snap the wrist for power. In elite forehands, forearm pronation adds almost nothing to racquet speed, while the shoulder adds about 45 to 48%. The wrist's job is to get out of the way.StrikeHow to hit a modern topspin forehandPrepare early and give yourself room to meet the ball in front. Racquet path and face orientation affect topspin, but they do not guarantee accuracy. In Kwon and colleagues’ collegiate sample, upward racquet velocity and a more closed face were associated with more spin. Use the contact drill to explore comfortable spacing, then test placement with a target.