Jumper's knee (also known as Patellar tendinitis)

Jumper's knee (also known as Patellar tendinitis)

Mitsutoshi Hayashi

Mitsutoshi Hayashi

Doctor of Medicine, specialist in the Japanese Society of Rehabilitation Medicine, specialist in the Japanese Society of Orthopaedic Surgery, specialist in the Japanese Society of Rheumatology, staff to strengthen JOC, and sports physician certified by the Japan Sports Association

Jumper's knee / Patellar tendinitis

Disease Overview

Jumper's knee, as its name implies, is knee sports disorder caused by overuse, often caused by jumping or landing in volleyball or basketball, or by repeated football kicking or dashing motions.

Cause and mechanism of onset


One of the factors is decreasing flexibility of the quadriceps muscle. In growing athletes, in particular, it is a chronic disorder that results when muscle growth fails to keep up with pace of bone growth, resulting in muscle stiffness that accumulates around the peripheral patella.


Frequent and prolonged flexion and extension of the knee joint with jumps or dashes can cause micro-damage to the patella periphery by repetitive over traction on the knee extension mechanism (pulling the quadriceps muscle add traction to patella, patellar tendon and tibial tuberosity). The condition can cause changes in the tendon parenchyma, such as bleeding, edema, mucoid degeneration (mucous degeneration of connective tissue), and fibrinoid degeneration (deposition of fibrinoid material in tissues, causing tissue damage and inflammation), resulting in minimal rupture and, rarely, complete rupture in the most severe cases.

Jumper's knee 1
Jumper Knee 2

Figure: Jumper’s Knee Mechanism
Repeated application of excessive traction to the knee-extension mechanism (pulling the quadriceps muscle into the patella, patellar tendon, and tibial tuberosity) causes micro-damage to the patella periphery


Age predilection

Age predilection
12-20 years old. It is particularly common among men in their teens.


There was no difference in the affected side between the left and right sides, but one-third of the players who complained of pain on the affected side had injury in both sides. Therefore, it is important to check the other side, even if the person feels pain on only one side.


35 of 108 patients reported pains at our medical check of the National Volleyball Team, for a rate of 32.4%.

Clinical Condition

There are pain and tenderness over the front of the knee during exercise (Photo 1), feeling heat and swelling. An important finding is that lying on the floor and bending the knee causes the buttocks to rise (Photo 2) to escape from tight pain on the front of the thigh.

Frequent site

The sites frequently affected are from the lower part of the patella to the insertion site of the patellar tendon (about 70%), from the upper part of the patella to the insertion site of the quadriceps muscle tendon (about 20%), and from the middle part of the patellar tendon to the attachment site of the tibial rough surface (about 10%).

Jumper's knee 1

Photo 1 Pain and tenderness, mainly from the patella to the insertion of the patellar tendon (anterior aspect of the knee)

Jumper Knee 2

Photo 2 Bending the knee of the patient with jumper’s knee, who is on one’s belly, rise a "buttock" to avoid pain.

Similar disease

[Osgood disease]
It is a growth disorder of tibial tuberosity that occurs mainly in boys between the ages of 10 to 15.

Treatment and rehabilitation


Because the measurement of treatment depends on the degree of pain, the stage of the disease is divided into four stages. Recently, braces and supports are recommended for primary prevention and prevention of recurrence.

[Phase 1]
If pain occurs after exercise, thorough stress on the anterior thigh and icing on the affected area after exercises should be performed. It is recommended to apply supports. (Photo4)
[Phase 2]
If pain appears before and after exercise, in addition to the abovementioned, pause from jumping, exercise therapy of the lower extremities, centered on the knees and hip joint, and icing on the area are recommended.
[Phase 3]
In case of pain affecting movement, rest from exercise on a monthly basis and stretching to improve muscle balance in the lower extremities are performed, followed by resumption of training after pain relief.

[Phase 4]
Suturing is necessary in cases of rupture.

To stretch the iliopsoas
Quadriceps muscle stretching

Photos 5 and 6 If you feel pain after the exercises, it is recommended to stretch the quadriceps muscle and iliopsoas. Please check for adequate stretching of the hip joint because both are less effective if the hip joint is not hyperextended.

Yoshizumi Iwasaki

Yoshizumi Iwasaki

NATA certified athletic trainers, certified athletic trainers from the Japan Physical Education Association, and chairman of the Japan Core Conditioning Association (JCCA)

Jumper's knee: Patellar tendinitis


Encouraging proper warm-up and cool-down before and after sports is the cornerstone of preventing overuse problems. Please be sure to perform sufficient stretching especially after hard exercises or matches (while the body temperature is still high immediately after exercise).
For jumper's knee, the quadriceps muscle has muscle aches, difficulty of climbing and descending stairs, and any signs of thigh pain (such as swelling of the entire leg) before the main symptoms. It is important to do the following procedures at this stage to prevent the development of symptoms.
・ Sufficient stretching
・ Icing and ice massage
・ Knead with massage

On-site evaluation and first aid

Basically, please icing on the area with pain. However, when the quadriceps muscle is overused and tense, the entire thigh is treated with icing at the same time.
When symptoms are severe enough to stop sports, the patient need to see a doctor. However, simply resting is not enough to relieve symptoms. Therefore, it is essential to perform icing while applying an anti-inflammatory analgesic or taking it by mouth under the doctor’s direction. If the inflammation in the affected area subsides, it is effective to relax the muscles of thigh with hot packs or other procedures.


Jumper’s knee supports are available on the market, as described in the doctor’s section. These supports are designed to prevent excessive force from being applied at the origin or insertion of the patellar tendon.
There are also many trainers who use Kinesio tape for jumper’s knee. It is important to adjust the amount of practice and the time of practice before overuse, as jumper's knee is a common problem with overuse.
If you experience more exercise or training hours, you had to know your condition, increase your stretching time, or take icing as needed. Massage between players may be helpful. Particular attention should be paid if you have alignment or movement problems.

Prevention stretching

・ Stretching of thigh
・ Stretching of adductor
・ Stretching of iliotibial band
・ Stretching of Popliteus muscle
It's important to stretch over sufficient time.

Related Sports Injuries