Metabolic energy expenditure during spring-loaded crutch ambulation.

ABSTRACT

CONTEXT Individuals using traditional axillary crutches to ambulate expend approximately twice as much energy as individuals who perform able-bodied gait. A relatively novel spring-loaded crutch now being marketed may reduce metabolic energy expenditure during crutch ambulation. This idea, however, had not yet been tested. OBJECTIVE: To determine whether the novel spring-loaded crutch reduces oxygen consumption during crutch ambulation, relative to traditional-crutch ambulation. A secondary purpose was to evaluate the design for subject-perceived comfort and ease of use. DESIGN: Within-subject. SETTING: Indoor track. PARTICIPANTS: 10 able-bodied men and 10 able-bodied women. INTERVENTIONS: The independent variable was crutch design. Each subject ambulated using 3 different crutch designs (traditional, spring-loaded, and modified spring-loaded), in a randomized order. MAIN OUTCOME MEASURES: The primary dependent variable was oxygen consumption. Secondary dependent variables were subject-perceived comfort and ease of use, as rated by the subjects using a 100-mm visual analog scale. Dependent variables were compared among the 3 crutch designs using a 1-way repeated-measures ANOVA (α = .05). RESULTS: Oxygen consumption during spring-loaded-crutch ambulation (17.88 ± 2.13 mL · kg⁻¹ · min⁻¹) was 6.2% greater (P = .015; effect size [ES] = .50) than during traditional axillary-crutch ambulation (16.84 ± 2.08 mL · kg⁻¹ · min⁻¹). There was no statistically significant difference (P = .068; ES = -.45) for oxygen consumption between spring-loaded-crutch ambulation and ambulation using the modified crutch (17.03 ± 1.61 mL · kg⁻¹ · min⁻¹). Subjects perceived the spring-loaded crutch to be more comfortable (P < .001; ES = .56) than the traditional crutch. There was no difference (P = .159; ES = -.09) between the spring-loaded and traditional crutches for subject-perceived ease of use. CONCLUSIONS: Compared with traditional axillary crutches, the novel spring-loaded crutch may be more comfortable but does not appear to benefit subjects via reduced metabolic energy expenditure.