Knee extension exercises, together with flexion angles, are collectively referred to as knee mobility exercises.
The knee joint is the site of more frequent injuries and osteoarthritic diseases, and is the basis for essential functions of daily life such as standing and walking. This is why the ability to straighten the knee joint is so important. If you can’t straighten your knee joint, you can’t even stand with one leg long and one leg short, and you will definitely walk with a limp. Not only is it very painful psychologically, but it is impossible to restore normal joint function. Even if the bending angle is good and the muscle strength is strong, many of the same movements cannot be completed.
Before the knee extension exercise, we need to pay attention to the following.
First of all, a word of caution: if both flexion and extension angles of the knee joint need to be practiced, attention should be paid to the arrangement of the exercises. Unless there is a special need, generally speaking the extension exercises should be separated from the flexion exercises for as long as possible, for example, one in the morning and the other in the afternoon. This is to avoid interactions that can counteract the effects of the exercises and increase inflammation and swelling of the joint due to excessive stimulation.
Afterwards, it should be noted that during the knee extension exercises, if the muscles of the back of the thigh or the joint capsule of the back of the knee feel a pulling sensation, or a slight pain from the pulling, this is normal and expected. Do not contract your muscles to fight this feeling, but try to relax them completely to adapt to the sensation. Otherwise, the exercise will become ineffective because the muscles that need to be stretched are contracting against each other.
It is also important to note that the weight of the sandbag used in stretching exercises should not be too heavy. The weight should be added so that the affected knee is still relaxed and does not instinctively contract the muscles against it because of the pain at once. If the whole exercise is 30 minutes, the first 5-10 minutes should be pain-free and the muscles and joints should be able to relax, and the pain should start to increase in the middle 10 minutes and continue until the last 10 minutes, when you basically reach your limit and need to hold on to hold on. This is the right intensity and volume.
It is also important to remember that throughout the stretching exercise, do not rest in the middle of the pain. If the contracted tissue is stretched and relaxed, it will quickly shrink and become shorter, and the exercise will have little effect. It will also increase inflammation and swelling due to the repeated stimulation of pulling and relaxing. So if you can’t hold on for 20-30 minutes, it means that the added load is too heavy and the intensity is too great, so don’t take a break or grit your teeth and stick to it, but you should adjust the weight and intensity and practice again.
The following describes the specific methods.
Sitting (or supine) knee extension.
Sitting or lying flat on your back. The ankles and feet are elevated with a pillow or something like that, leaving the lower leg and the underside of the knee completely empty. Afterwards, relax the muscles completely and rely on the weight of the leg to naturally drop down to reach full extension. If necessary, you can add a heavy object such as a sandbag to the thigh area above the knee joint to increase the intensity of the exercise. Note! It’s “above the knee thigh area”! Putting weights directly on the knee joint will increase the pressure between the patella and femur, and prolonged compression will cause new injuries!
The general rule is to hold this position and practice for 20-30 minutes. This method is suitable for the pre-surgical period, and for patients with only a slight limitation of the knee extension angle (only a little).
Prone heavy suspension knee extension.
Prone, which is lying face down on the bed. The lower leg and foot below the knee are to be outside the edge of the bed, suspended over the edge of the bed. Again, the muscles are completely relaxed and full extension is achieved by the natural dropping of the weight of the leg. If necessary, weights such as sandbags can be added to the ankle (ankle) to increase the intensity of the exercise.
The general idea is to hold this position and practice for 20-30 minutes. This method is suitable for patients in the mid to late post-operative period, and also for patients with a significantly more limited knee extension (that is, a little more poor extension).
Seated prone N-cord retraction knee extension.
The name of this exercise is a bit long because I wanted to describe the movement clearly. It does not necessarily mean that the angle of movement of the joint is normal if there is no joint adhesion. What affects the angle is also the “extensibility” of the “antagonist muscle”. In layman’s terms, this means whether the relevant muscles and tissues are long enough, and whether they are flexible enough. If not, the angle is also affected!
For knee flexion, the antagonist muscle is the quadriceps, and for knee extension, it is the opposite of the N cord muscle. So in order to improve the angle of knee extension, there is this exercise “N cord muscle pulling”.
Although the name is long, but the posture is simple. It is to sit on the bed with legs straight and together, bend forward and try to touch your toes with your hands. Should feel the back of the thighs have a significant pulling sensation to indicate that the movement is correct.
The point of the action is: try to bend the hip (hip joint, that is, the hip bone), rather than bending over. This can feel the pulling sensation of the N rope muscle on the back of the thigh, otherwise the pulling is the waist and back. After feeling obvious pulling pain after stopping to keep still, or a slight trembling, 1-2 minutes after the tissue adapted, pulling feeling gradually disappeared or reduced, then pull forward.
It is usually necessary to maintain this position and practice for 10-15 minutes. This method is applicable to all periods after surgery, mainly for patients with limited knee extension and also with significant contracture of the N cord muscle (that is, the above two positions can be pressed straight, but active extension is poor).
Finally, it must be reminded that patients with problems in the lumbar spine should never do this exercise, such action is to increase the pressure on the lumbar spine and aggravate the lumbar disc herniation!
Leg press type N rope muscle pulling knee extension.
Find a height and waist about the same, or a slightly higher fixed object. After that, lift the affected leg up and do the leg press action. You can also try to use your hands to touch your toes to increase the intensity. The same exercise is done for the antagonist N cord muscle that pulls the knee extension. You should feel a significant pulling sensation on the back of the thigh to indicate the correct movement.
The point of the movement is also: try to bend the hip (hip joint, that is, the hips), rather than bending. This can feel the pulling sensation of the N rope muscle on the back of the thigh, otherwise the pulling is the back and back. After feeling obvious pulling pain after stopping to keep still, or a slight trembling, 1-2 minutes after the tissue adapted, pulling feeling gradually disappeared or reduced, then pull forward.
Generally, it is necessary to maintain this position and practice for 10-15 minutes. This method is suitable for all periods after surgery, mainly for patients with limited extension of the knee and significant contracture of the N cord muscle (that is, the first two positions can be pressed straight, but active extension is poor).
Lunge N cord pulling knee extension.
Hold a wall or a table or something fixed. The affected leg is then placed in a “lunge” position behind. The front healthy leg is slightly bent, while the body weight is forward, and the back leg is stretched straight and pulled. You should feel a significant pulling sensation on the back of the thigh to indicate that the movement is correct.
The key point of the movement is: the back of the affected leg should try to extend the knee as hard as possible, not just passively follow the body movement. This is the only way to feel the pulling sensation of the N cord muscle on the back of the thigh, and to pull the joint capsule on the back of the knee and the calf muscles (the calf muscles also pass through the knee joint and have an effect on the straightening of the knee!) This has an effect on knee extension! After you feel the obvious pulling pain, stop and keep still, or tremble slightly, 1-2 minutes after the tissues have adapted, and the pulling sensation gradually disappears or decreases, then pull forward again.
Generally, it is necessary to maintain this position and practice for 10-15 minutes. This method is suitable for all periods after surgery, mainly for patients with limited knee extension, as well as significant contracture of both the N cord muscle and the calf muscle (that is, the first two positions can be pressed straight, but active extension is poor).
To summarize.
There is no need to repeat the importance of being able to return the knee to a normal angle of extension. It is also important to remember not to just look at the angle values in books or rehabilitation programs.
When practicing, the most important thing is to see what the maximum angle of extension is for the leg that is not injured. Some people have significant hyperextension, which is a little more than 0°, about 5-10°. It’s a negative angle. So before you practice you must take a good look at what your maximum straightening angle is before you start to practice with control. You can refer to the previous article, which describes in detail how to measure your knee extension angle.
These are exercises for different levels and situations of limited knee extension. In general, no matter which method is used, it should be controlled for about 30 minutes, and only continuous stretching can be safe and effective. Absolutely no violent and violent leg presses! Too long and repetitive exercises will overstimulate the joint and cause increased swelling and inflammation of the knee joint, which is detrimental to the recovery of the joint function!
Pay attention to the antagonist muscles of the knee, the N cord muscles, during the exercise. This is very good for increasing the extensibility and flexibility of the antagonist muscles and can help improve the flexibility of knee extension.
The above, although all do not need special equipment, can be practiced at home by themselves, but due to the different injuries and surgeries of each person, tissue conditions are different, the exercise must still be assessed and guided by a professional doctor therapist, that you are suitable for a particular exercise, before you can do. Blindly practicing on your own in one-sided pursuit of angle will only cause danger! Remember! Remember!
It is also important to remind that the joint release treatment done by a professional therapist in a regular hospital is, on the surface, similar to the methods described above in some positions, but in fact it is a very operational treatment technique that cannot be learned just by looking at it. If the situation requires that the angle does not progress or is difficult to progress or even regress after practicing on your own, you must go to a regular hospital to have joint release treatment done by a professional therapist!