Crutches are frequently used as a temporary mobility aid following an injury or surgery that prevents full weight-bearing on a lower limb. This change requires the body to engage muscles in new and demanding ways to maintain balance and propel forward. Does this modified form of ambulation actually lead to muscle development in the upper body and core?
Strength and Endurance Adaptations
While using crutches is unlikely to cause significant muscle hypertrophy, the repetitive action does induce measurable physiological changes. The body experiences a localized increase in muscular strength and endurance, particularly in the shoulder and arm regions. This conditioning results from the need for continuous, low-level force production over long periods of movement. The type of muscle fibers primarily recruited are slow-twitch, or Type I, fibers, which are designed to resist fatigue. This constant recruitment enhances the muscle’s ability to maintain contraction, increasing its endurance capacity rather than its bulk.
Specific Upper Body and Core Muscles Engaged
The act of crutch walking transforms the upper body into the primary engine for locomotion, activating a specific chain of muscles. The triceps brachii becomes a major mover, working to extend the elbow and push the body upward and forward with each step, bearing the majority of the body’s weight. The shoulder girdle muscles are equally involved, with the deltoids stabilizing the arm and positioning the crutches during the swing phase of the gait. The large latissimus dorsi muscles of the back and the pectorals (chest muscles) are also activated to provide a stable base and downward force for safely transferring weight to the handgrips. The entire core musculature, including the abdominal and lower back muscles, constantly contracts to stabilize the trunk and maintain posture.
Atrophy in the Non-Weight-Bearing Limb
The physical gains in the upper body are contrasted by a predictable loss of muscle mass in the injured, non-weight-bearing lower limb. This process is known as disuse atrophy and can begin rapidly after immobilization. Muscle mass loss can start within two to three weeks of disuse. Studies have shown that the cross-sectional area of muscles in the thigh and calf can decrease significantly, sometimes by over 8% in just four weeks of non-weight-bearing status. The large leg extensor muscles, such as the quadriceps, which are designed for powerful weight-bearing, experience a substantial reduction in activation when the leg is not being used. This loss of muscle tissue is accompanied by a decrease in muscle strength that is disproportionately greater than the initial loss of mass. Mitigating this atrophy requires a structured approach, often involving isometric exercises and physical therapy to safely maintain muscle tone until full weight-bearing can be resumed.
Proper Crutch Technique for Safety and Efficiency
To maximize the benefits and minimize the risks of crutch use, proper technique is necessary for both safety and muscle engagement. The correct crutch fit is paramount, requiring that the top of the crutch pad be positioned approximately two finger-widths below the armpit. Weight should always be supported by the hands pressing down on the handgrips, not by leaning on the armpit pads. Leaning on the armpit can compress nerves and blood vessels in the brachial plexus, potentially causing numbness or nerve damage.
The handgrips should be set so the elbows are slightly bent, about 30 degrees, allowing for effective pushing power. A common gait involves the three-point pattern: the crutches move forward first, followed by the injured leg, and then the strong leg steps through. Maintaining this sequence and keeping the crutches slightly out to the sides forms a stable triangle, which improves balance and ensures that the correct upper body and core muscles are doing the work.