The practice of walking backward, often termed retrowalking, is a simple change in locomotion that offers distinct advantages for knee health compared to traditional forward movement. This exercise is frequently incorporated into physical therapy and rehabilitation programs because it fundamentally alters the forces acting on the knee joint and shifts the way specific muscle groups are activated. Understanding these biomechanical differences explains why moving in reverse can be a beneficial strategy for managing chronic knee discomfort and improving overall joint stability.
Changes in Joint Loading and Impact
Walking backward fundamentally changes the impact mechanics on the knee joint, primarily by reversing the typical gait cycle. When moving forward, the gait typically begins with a heel strike, which creates a significant impact shock that travels up the leg into the joint. Retrowalking, however, causes the foot to land with the toes or the ball of the foot first, which provides a natural cushioning effect before the heel touches down. This toe-first contact allows for a smoother transition of weight, which substantially reduces the magnitude of the initial ground reaction forces on the knee.
The altered weight distribution during the stance phase also decreases the load on the patellofemoral joint, where the kneecap (patella) glides over the thigh bone (femur). Studies indicate that backward walking reduces the External Knee Adduction Moment (EKAM). The EKAM correlates with compressive forces on the inner, or medial, compartment of the knee, which is often affected in conditions like osteoarthritis. By lowering this moment, retrowalking decreases the stress and shear forces placed on the joint surfaces, making it a lower-strain activity than walking forward.
This reversal of movement also affects the knee’s range of motion. Unlike forward walking, which requires the knee to absorb shock and then push off, walking backward encourages greater use of the knee in an extended position during the leg’s contact phase. This helps to promote full knee extension, a range of motion that can become limited following injury or due to conditions like knee arthritis.
Targeted Muscle Strengthening
The biomechanical shift during retrowalking also translates into a significant change in how the muscles surrounding the knee are recruited and strengthened. Forward walking heavily relies on the hamstring and calf muscles to eccentrically decelerate the leg, while backward walking emphasizes concentric muscle work, particularly from the quadriceps (the muscles on the front of the thigh). Concentric contractions, where the muscle shortens while generating force, are generally less stressful on the joints than eccentric ones.
This increased reliance on concentric quadriceps strength is especially beneficial for knee stability. Crucially, retrowalking has been shown to increase the activation of the vastus medialis obliquus (VMO), which is the teardrop-shaped muscle located just above the knee on the inner thigh. The VMO is responsible for the final degrees of knee extension and plays a significant role in ensuring the kneecap tracks correctly within its groove on the femur.
Strengthening the VMO is a primary goal in treating patellofemoral pain syndrome, often called runner’s knee, where improper tracking of the kneecap causes pain. By selectively increasing VMO activation, retrowalking helps to correct muscle imbalances and provides better dynamic stabilization for the kneecap.
The continuous need for controlled movement and balance in reverse also engages the hip flexors and extensors more intensely than forward walking. This contributes to a more stable support system for the entire lower limb.
Incorporating Retrowalking Safely
For individuals new to the practice or those with existing knee issues, initial attempts at retrowalking should be performed in a controlled environment to mitigate the risk of falling or tripping. Using a treadmill is highly recommended, as it provides a flat, predictable surface and allows the user to hold onto handrails for support and balance. A slow starting pace, such as 2 miles per hour, is advisable until the new movement pattern becomes comfortable.
When beginning, focus on maintaining an upright posture and taking short, deliberate steps, rather than trying to achieve speed or distance. For those using a treadmill, start with a flat incline and gradually increase the duration of the activity, perhaps starting with five to ten-minute intervals.
A general rule for progression is to increase the duration or intensity by no more than ten percent per week to allow the muscles and joints time to adapt to the new demands. Individuals with severe balance concerns or significant knee pain should consult a physical therapist and may require a spotter or the continuous use of supportive structures, like a wall or parallel bars, to ensure a safe experience.