Tennis

For Patients

The Principle

Whether a foot slides or sticks changes everything about what the joint above it has to absorb.

A foot that slides lets the body slow down over a longer distance, which lowers the force.

A foot that sticks stops the body suddenly and sends the difference up the leg.

At the Knee

Tennis is mostly short sprints sideways, a stop, a stroke and a recovery, repeated for hours.

On clay the foot slides into the shot, which spreads the deceleration out.

On hard courts the foot grips, so the stopping happens through the ankle, knee and hip instead. 3.4.2 covers the forces.

The serve adds a jump and a landing on one leg, usually the same leg every time. 3.14.8 covers landing.

Clinical Relevance

The surface a player uses most is relevant history, because it changes the loading.

Pain at the front of the knee in a tennis player is usually about repeated loading rather than damage. 6.60 covers anterior knee pain.

A sudden twisting injury during a change of direction is a different problem and needs assessing.

No injury rates are given here. No source was available to check them against.

For Medical Students

The Principle

Deceleration is work, and the work has to be done somewhere: by friction at the foot, by muscles lengthening, or by tissue deforming.

Removing friction gives the muscles more time and lowers the peak. Adding friction does the opposite.

Surface and footwear are therefore mechanical variables rather than comfort choices.

At the Knee

Lateral deceleration loads the knee in a combination of flexion, valgus and rotation, which is the same family as a cutting manoeuvre. 3.14.6 covers cutting.

A sliding stop on clay lengthens the deceleration, lowering peak ground reaction force and peak knee moment.

The open stance forehand loads the trail leg in internal rotation while it decelerates, which is a specific tennis exposure.

The serve produces a single leg landing on the same limb repeatedly, loading the extensor mechanism. 3.12.3 covers the pressures.

The dominant presentation is anterior knee pain and patellar tendinopathy rather than instability. 6.64 covers tendinopathy.

What Changes It

Surface and shoe traction, which set whether sliding is possible.

Playing volume and match length, which set cumulative exposure. 3.14.4 covers the argument.

Stance used for groundstrokes, since open and closed stances load differently.

Hip and trunk control during lateral deceleration. 3.12.7 covers dynamic valgus.

Age, since the sport is played across a very wide age range.

Clinical Relevance

Ask which surface the patient plays on and in what proportion, because it changes the loading.

Expect a one sided presentation, since the sport loads one limb preferentially.

Treat anterior knee pain here as a loading problem and take a volume history. 3.12.9 covers the condition.

Avoid quoting injury rates, which this page does not, because no source was available.

MRCS Level

The Principle

Tennis illustrates a general point better than any other sport here: the shoe surface interface is a modifiable determinant of knee load, and it is almost never part of a clinical history.

Traction is a property of the pair, not of the shoe or the court alone.

That makes it a genuinely actionable variable and one the patient controls.

At the Knee

Peak knee moments in lateral deceleration fall when sliding is permitted, which is the mechanical account of clay's reputation.

The trade is volume: longer rallies and more court coverage raise cumulative load even as peak load falls. 3.14.4 covers cumulative load.

Open stance strokes load the trail limb in internal rotation at speed, and the anterolateral structures resist that component. 3.11.5 covers internal rotation control.

Serve landing is a repetitive single leg impact on the same limb, which produces the asymmetrical presentation characteristic of the sport.

Acute cruciate injury occurs by the familiar cutting mechanism and is less prominent here than in field sports. 3.7.14 covers it.

What Changes It

Shoe and surface pairing, which sets traction and is modifiable immediately.

Playing volume, which is the cumulative term.

Technique, particularly stance selection and recovery footwork.

Fatigue within long matches, which degrades deceleration control.

Prior injury and asymmetry, which this sport tends to amplify.

How It Is Measured

Instrumented court studies with force plates or pressure insoles, which measure real movements in a limited number of players. 3.16.8 covers wearables.

Mechanical traction testing of shoe surface pairs, which is reproducible and excludes the player.

Laboratory lateral cutting protocols, which generalise to tennis imperfectly. 3.14.6 covers them.

Match load monitoring from wearables, which captures volume.

No measurement of knee tissue load in tennis exists, so the surface argument rests on ground reaction force and moment rather than on tissue stress.

Clinical Relevance

Ask about shoe and surface as a pair, since traction is a property of both and is modifiable.

Expect and look for asymmetry, because the sport loads one limb preferentially.

Balance the peak load argument for clay against its volume cost when advising.

State that the surface argument rests on joint moments rather than on measured tissue stress.

Weigh the player's age, physiology, comorbidities, knee demand, psychological state and their own ideas, concerns and expectations, since this sport spans ages and ambitions more widely than most.