A knee ligament injury, such as a tear to the anterior cruciate ligament (ACL) or medial collateral ligament (MCL), involves damage to the connective tissues that stabilize the knee joint. These injuries require careful rehabilitation to restore function and strength. Cycling is frequently recommended because it is a controlled, non-weight-bearing activity that allows for joint movement with minimal stress. When performed correctly and with professional guidance, cycling can be highly beneficial for rebuilding strength and mobility.
Cycling’s Therapeutic Mechanism for Ligament Healing
Cycling offers a unique advantage over high-impact exercises by providing a controlled, closed kinetic chain movement. In this exercise, the foot remains fixed to the pedal, stabilizing the lower leg and minimizing the sliding of the shin bone (tibia) relative to the thigh bone (femur). This stability is important for healing ligaments, as it reduces shear forces that can place stress on tissues like the ACL.
The non-weight-bearing nature of cycling, where the saddle supports the body’s mass, helps to unload the knee joint, preventing the direct impact that occurs in activities like running or jumping. The cyclical motion promotes the strengthening of surrounding muscles, including the quadriceps and hamstrings. These muscles provide dynamic stability, acting as a protective shell for the healing ligament.
The continuous, low-resistance motion also encourages joint mobility and helps to circulate synovial fluid, which nourishes the joint cartilage. This controlled, therapeutic stress is necessary to enhance recovery without overloading the vulnerable ligament. Recumbent bikes may be preferred early in rehabilitation, especially for ACL injuries, as the altered position can reduce the load compared to an upright bike.
Bike Setup and Pedaling Form
Adjusting the bicycle setup is necessary to ensure the movement remains therapeutic and does not introduce harmful forces to the recovering knee. The correct saddle height is a primary consideration. A saddle that is too low forces a deeper bend in the knee, increasing compression and stress on the joint. Set the saddle so the knee has only a slight bend, approximately 5 to 10 degrees, when the pedal is at its lowest point (six o’clock position).
Maintaining a high cadence, or pedaling speed, with low resistance is essential to minimize strain on the joint. Aim for a pedal revolution rate of around 90 to 100 revolutions per minute (RPM) to prevent the need to push forcefully against heavy resistance. This light and fast pedaling technique reduces the overall force applied to the knee with each stroke. Conversely, a low cadence of less than 80 RPM requires more muscular effort, which increases stress on the joint structures.
The position of the cleats on the shoe also requires specific attention, as they control the foot’s angle throughout the pedal stroke. Cleats should be adjusted to allow the foot to track straight, preventing the knee from falling inward or outward. Rotation of the foot can create rotational forces in the knee, potentially destabilizing the joint and placing excessive force on the healing ligament. For early rehabilitation, some professionals suggest using flat pedals, as this makes it easier to stop and reduces the rotational force applied when clipping in and out.
The Rehabilitation Progression
Before beginning any cycling routine, secure clearance from a physician or physical therapist to ensure the activity is appropriate for the specific stage of injury recovery. The initial phase should focus on restoring range of motion and is typically performed on a stationary bike. Stationary cycling offers a highly controlled and safe environment, eliminating the risk of sudden movements, falls, or unpredictable terrain changes inherent to outdoor riding.
A common requirement before starting is the ability to achieve a minimum of 100 degrees of knee flexion, which is needed to complete a full pedal revolution without excessive strain. Initial sessions should be very short, perhaps 10 to 15 minutes, with zero resistance. The primary goal is pain-free movement, and the duration and resistance should only be increased gradually after successfully completing the previous session without any pain flare-ups.
Progression from a stationary to an outdoor bicycle should be cautious, starting on flat routes to avoid the increased stress hills place on the knee joint. The transition should only occur once the individual can comfortably tolerate light resistance on a stationary bike for an extended duration, such as 30 minutes. Throughout the rehabilitation process, listening to the body and avoiding any activity that causes sharp or persistent pain is the most important guiding principle.