People from all walks (or runs) of life experience knee pain. A variety of factors contribute to this, such as age, inactivity, long-duration exercise, or injury. While exercises such as knee extensions and hamstring curls have long been used for knee strengthening, a simpler exercise exists that specifically targets the stability of the knee joint. Closed-chain extension (CCX) causes a short stretch followed by a soft contraction primarily of the quadriceps. Closed-chain extensions are safer than squats, and unlike knee extensions and hamstring curls, include a compound movement (the use of more than one muscle group).

Closed-chain extensions can be done with zero weight and only require a step, box, or other elevated surface solid enough to withstand a person’s body weight. In the starting position of CCX, one foot is placed on an elevated surface, while the other foot is kept off the ground. Both knees are straight in the beginning of the exercise, with the leg not touching the ground positioned slightly in front of the body, as demonstrated in Figure 1. Once this position is reached, the weight-bearing knee is gently bent until the knee cap is in-line with the big toe from the view of the person performing the exercise, as displayed in Figure 2. The knee is then straightened back to the original position.

Figure 1

Figure 2

Another great aspect of CCX is that it does not have to be performed in a fitness center. Surfaces in one’s home, such as stairs or front steps, adequately provide the only “equipment” needed for this exercise.

While the other lifts mentioned are also great for strengthening the knee, closed-chain extensions are a structural lift that improve joint stability by not only strengthening the muscles surrounding the knee, but also by improving one’s balance. The benefits of a stronger knee include ease in performing daily activities such as walking or jogging, reduced pain in any given movement, and reducing the probability of future knee injuries.

Performing this lift twice a week for two sets of ten repetitions on each leg is a great way to improve the health of the all-important knee joint. Whatever the cause of pain, the closed-chain extension is an exercise no knee should be without.