Tennis injuries to hip and knee

Marc Darrow, MD, JD.

Many tennis players take lessons on how to improve their open forehand stance and generate power on the return. As research has shown the open stance forehand is a pretty traumatic service and it can significantly impact the knee and hip. Over time the open forehand stroke can be a contributing factor in the development of a “tennis knee” or a “tennis hip.”  As these knee and hip injuries get more nagging, the player will employ braces, tapes, and anti-inflammatories to keep themselves on the court. As the injury progresses cortisone may be suggested. Eventually the injury will cause the player to stop playing or to seek other treatments including arthroscopic surgery. In this article I will suggest the possibility of injection treatments such as Platelet Rich Plasma or bone marrow aspirate stem cell therapy as an option to repair knee and hip damage and strengthen the joint.

The impact on the knee in an open stance forehand

A May 2021 published study (1) examined the open stance forehand and concluded it was more traumatic for the knee than the neutral stance forehand. The study authors compared motion, kinematics and kinetics at the knee during three common forehand stroke stances:

  • Attacking neutral stance
  • Attacking open stance
  • Defensive open stance

They then sought out to determine if the open stance forehand induces higher knee loadings:

  • Eight advanced tennis players performed eight repetitions of forehand strokes with each stance:
    • Attacking neutral stance: forward run and stroke with feet parallel with the hitting direction,
    • Attacking open stance: forward run and stroke with feet perpendicular to the hitting direction,
    • Defensive open stance: lateral run and stroke with feet perpendicular to the hitting direction at maximal effort.

The findings? The defensive open stance: a lateral run and then stroke had increased vertical ground reaction forces, maximum knee flexion and abduction angles, range of knee flexion-extension, peak of compressive, distractive and medial knee forces, peak of knee abduction and external rotation torques. What does all this mean? There is a lot of strain and forces on you knee when you are facing your opponent in the open stance and returning the ball. Consequently, the defensive open stance appears potentially more at risk for given knee injuries.

How about the hip?

The same authors also examined the hip. They published this research in December 2020 (2) Here they wrote: “The open stance forehand has been hypothesized by tennis experts (coaches, scientists, and clinicians) to be more traumatic than the neutral stance forehand as regards hip injuries in tennis.”

Again, the study authors looked at:

  • Attacking neutral stance
  • Attacking open stance
  • Defensive open stance

Their findings imply that the defensive open stance increased hip joint angles and loading, thus potentially increasing the risk of hip overuse injuries. The Defensive open stance-induced hip motion could put players at a higher risk of posterior-superior hip impingement compared with the attacking neutral stance and attacking open stance.

Everyone says the neutral stance is better, but during the match I find myself returning into the open or semi-open stance

Many tennis players will say things like, when I rotate my trunk or, turn my shoulder in open or semi-open stance my lead hip hurts. It does not hurt when I am in neutral stance though. I have to alter my game.

It can be challenging to alter a game when your natural tendency is to return the ball anyway you can. In the defense open stance forehand, the muscles, ligaments and tendons, the soft tissue that holds the hip joint together are put under tremendous joint loading (the weight of the body) stress.  Then from the planting of your feet comes the concentric (muscle shortening contraction) torque that generates the power of the return. Wear and tear or repetitive injury can be common in this motion. This is where problems of the labrum, ligament laxity and tendon wear can cause pain and reduced play performance.

Treating knee and hip wear and tear

Starting with the knee. All sports that require cutting, quick stops, acceleration and change of direction like tennis, racquet sports, basketball, football share a common thread of accelerated and extreme forces that strain the knee ligaments.

The knee can be injured in many ways during a tennis match including ligament injury, whether acute tear or degenerative micro-tearing. The ACL (anterior cruciate ligament), the MCL (medial collateral ligament) and the PCL (posterior cruciate ligament), are powerful ligaments responsible for holding the knee, the thigh bone (femur) and the shin bone (tibia) in their proper place in respect to each other.

When these ligaments suffer from excessive wear caused by a twisting motion they can overstretch and become lax. When the thigh and shin bone are allowed to become hypermobile they can grind down and wear out the protective padding between them, the meniscus and the articular cartilage.

There are many treatment options available to the athlete. Most physicians will recommend a conservative route rich in anti-inflammatory medications, ice, pain-killers, and rest. When these options fail, as most times they do, the next conservative option is to “live with it,” or have the surgery.


1 Martin C, Sorel A, Touzard P, Bideau B, Gaborit R, DeGroot H, Kulpa R. Influence of the forehand stance on knee biomechanics: Implications for potential injury risks in tennis players. Journal of sports sciences. 2020 Dec 7:1-9.
2 Martin C, Sorel A, Touzard P, Bideau B, Gaborit R, Degroot H, Kulpa R. Can the Open Stance Forehand Increase the Risk of Hip Injuries in Tennis Players?. Orthopaedic Journal of Sports Medicine. 2020 Dec 11;8(12):2325967120966297.


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