Accelerating Recovery Following a Lower-Extremity Fracture Through Speed HIIT

Lower extremity trauma is one of the largest medical burdens in the military costing almost $2 billion annually and resulting in the highest percentage of days on limited duty [1, 2]. These injuries often result in long-term limitations in physical function and ability to return to deployment readiness [1, 2]. Consequently, an unmet need remains to test novel rehabilitation programs to optimize the recovery of service member¡¦s physical function to return them to effectively carry out the mission [3]. The lack of novel rehabilitation programs to promote early return of function culminates in poor physical outcomes and limited ability to return to duty. Our scientific premise is strengthened by several small studies which show intriguing evidence of continued impairments in muscle strength and gait mechanics 1 to 3 years following surgical fixation of a lower extremity fracture [4-7]. These impairments result in a devastating decline in an individual¡¦s ability to engage in activities of daily living with 20-42% of individuals still unable to return to work 7 years after surgery [6, 8]. Individuals that return to work are limited in approximately 25% of their job demands [1]. This indicates a critical need for programs that improve gait speed, gait mechanics, and performance on functional tests to facilitate reintegration to full duty status. Our pilot work (Fig 1) is the first data to show that the lack of effective rehabilitation protocols results in significant strength and functional impairments 1 year after surgery. One key finding from our pilot work is that patients continue to walk with preferred slower gait speed resulting in lower distances covered during the sixminute walk test (6MWT) as compared to healthy adults (Fig 2). These results agree with other work that studied fractures prevalent in the military, finding protracted, slower walking speeds two years after lower extremity fracture [9]. Our pilot data also indicate significant differences between injured and uninjured limb loading rate, impulse, and stance time (N=48, p