When a lower-body injury requires the temporary use of crutches, the body must adapt to a new method of movement. Crutches allow a person to walk and maintain mobility while reducing or eliminating weight-bearing on the injured leg. This reliance on the arms and upper body raises a common question: does this activity effectively build arm muscle? The mechanics of crutch walking shift the burden of propulsion and stabilization entirely to the upper body.
Strength, Endurance, and the Physics of Crutching
Using crutches primarily develops muscular endurance rather than significant muscle hypertrophy, which is the increase in muscle size or bulk. Muscle growth requires high-intensity resistance, often achieved through lifting heavy weights with low repetitions, a principle known as progressive overload. Crutching is a moderate-load activity performed for long durations and a high number of repetitions throughout the day. This sustained activity trains muscle fibers to resist fatigue and efficiently use oxygen, which defines muscular endurance. While new users experience initial strength gains as the nervous system adapts, crutch walking does not provide the intense resistance needed for substantial muscle size increase.
The Key Upper Body Muscles at Work
Crutch walking heavily engages the muscles responsible for pushing the body upward and stabilizing the shoulder girdle.
Propulsion and Stabilization
The triceps brachii, the primary elbow extensor, exerts force downward on the handgrips to lift the body during the push-off phase. Crucial for stabilization is the latissimus dorsi, a large back muscle that depresses the shoulder girdle, preventing the body from sinking between the crutches. The posterior deltoid muscles also assist the lats in this stabilizing motion, coordinating the shoulder joint while propelling the body forward.
Grip Strength
The forearm and grip muscles are constantly under tension to maintain a firm hold and control over the crutch handgrips. These muscles are responsible for the sustained, isometric contraction needed to keep the crutches firmly in place. The continuous engagement of these groups leads to improved muscle tone and fatigue resistance in the upper body.
Proper Technique for Safety and Muscle Engagement
Correct crutch technique is necessary to ensure proper muscle engagement and prevent injury. Weight must be borne entirely by the hands and wrists, pressing down on the handgrips, for the triceps and latissimus dorsi to function effectively. The handgrips should be adjusted so the elbows are slightly bent (about 20 to 30 degrees) when grasping them.
It is imperative to avoid resting or leaning on the padded tops of the crutches with the armpits (axilla). Placing weight on this area compresses the nerves and blood vessels, which can lead to axillary nerve damage, or crutch paralysis. Leaning on the handgrips allows the muscles of the arm and back to take the load, maximizing engagement and minimizing the risk of nerve injury.