Using crutches is surprisingly exhausting, extending far beyond discomfort in the hands and armpits. This profound fatigue is a complex physiological challenge resulting from a complete overhaul of the body’s mechanics. The sudden demand for the upper body to perform the work normally handled by the powerful leg muscles creates a massive energy deficit. Understanding the shift in energy consumption, localized strain, and hidden mental effort clarifies why crutch ambulation is so draining.
The Drastic Increase in Metabolic Demand
The most significant factor contributing to exhaustion is the massive, inefficient redirection of energy required for crutch walking. Normal human gait is an energy-efficient process, relying on the pendulum-like swing of the legs to conserve momentum. When a person uses a three-point crutch gait, this natural efficiency is lost, forcing the body to perform constant, active muscular work to propel and support itself.
Studies comparing crutch ambulation to normal walking show a substantial physiological cost, with the energy expenditure often measuring two to three times higher than unassisted walking at the same speed. This spike in physical effort translates directly into a higher demand for oxygen consumption (\(\text{VO}_2\)), the technical measure of aerobic energy use. The cardiovascular system must work harder to supply this demand, leading to a significantly elevated heart rate.
For many users, this immediate and high-intensity demand can quickly push the body into an anaerobic state, a condition typically associated with strenuous exercise. The heart rate of a patient using a three-point crutch gait can increase by over 50% compared to their baseline walking rate, sometimes approaching the peak levels seen during maximal upper-extremity exercise. This forced exertion, sustained for even short distances, is the primary scientific reason the body feels completely worn out after just a few minutes of mobility.
Specific Musculoskeletal Strain and Overload
The feeling of fatigue is localized intensely in the upper body because the arms and shoulders are suddenly tasked with bearing the entire body weight. This unnatural load leads to the sustained overuse of muscle groups that are not designed for continuous weight-bearing and propulsion. The triceps brachii muscles, located on the back of the upper arm, become heavily taxed as they perform the powerful push-off required to lift the body off the ground.
These pushing muscles work in tandem with the large stabilizing muscles of the back and torso, particularly the latissimus dorsi and the pectorals. The latissimus dorsi is a crucial muscle for crutch walking, as it helps depress and stabilize the shoulder girdle under the downward force of the body weight. The small muscles of the shoulder, including the rotator cuff, are placed under repetitive strain as they constantly stabilize the shoulder joint with every step, increasing the risk of overuse injuries and localized pain.
An additional source of strain, often compounding the sense of weakness and fatigue, is the risk of “crutch palsy.” This condition is a compression injury to the nerves in the armpit, specifically the radial nerve or the brachial plexus. If the crutch pads are improperly positioned directly into the armpit, they can compress these sensitive nerve bundles against the humerus bone. This nerve irritation can cause pain, weakness, and loss of function in the forearm and hand, making it difficult to grip the crutches and directly contributing to overall physical exhaustion.
Hidden Contributors to Overall Fatigue
Beyond the physiological and muscular strain, a significant portion of the total fatigue comes from the brain’s continuous, demanding effort, known as cognitive load. Unassisted walking is an automatic process that requires little conscious thought, but crutch use demands constant attention to balance, timing, and coordination. The user must continuously plan the placement of the crutches and the “good” foot, negotiate obstacles, and manage uneven terrain, all of which deplete mental resources. This mental effort is a form of neurobiological exhaustion, where the brain’s constant vigilance diminishes a person’s overall mental energy, leading to a feeling of generalized fatigue.
People using crutches often overestimate their walking speed, suggesting a disconnect between perceived effort and the slow rate of travel, which can be mentally discouraging. Poorly fitted equipment and the underlying injury also contribute to exhaustion. Crutches that are too tall or too short force the body into awkward postures, leading to secondary strain on the neck and lower back. This poor alignment forces the healthy leg to absorb extra load, compounding systemic fatigue. Managing the pain from the original injury requires continuous neurological input, adding an unrecognized layer to the overall feeling of being worn out.