Early Ambulation After Injury Is Associated With Increased Muscle Size and Strength

Background: Trauma and management of injuries can result in reduction or loss of mobility, which can lead to skeletal muscle deconditioning and sustained disability. Prior investigators have examined changes in skeletal muscle due to injury and immobility separately. The muscular consequences of combined immobility and trauma have not been systematically investigated. Objective: The purpose of this study was to explore the association of time to first ambulation with skeletal muscle size and strength in patients after major trauma. Methods: Adults (N = 19) admitted for major trauma (Injury Severity Score [ISS] > 15) provided daily measures of muscle size (ultrasound) and strength (dynamometry) during hospitalization. Participants were grouped based on time to first ambulation. Repeated measures analysis of variance was used to compare muscle measures between the groups across 5 days while controlling for age and gender. Results: Participants were primarily male (63%) aged 40 ± 17 years with a mean ISS of 21 ± 4. Early ambulation was associated with a 10% increase from baseline in bicep size on Days 3 and 4 and a 15% increase from baseline on Day 5. There were no changes in rectus femoris size in either group. The early ambulation group was significantly stronger than the delayed ambulation group throughout the study in measures taken with the biceps (22%–37%) and quadriceps (26%–46%). Conclusion: Early ambulation following major trauma was associated with increased bicep size and greater muscle strength in the biceps and quadriceps muscles over time.