Reduction of Risk for Low Back Injury in Theater of Operations

The investigators will conduct a controlled clinical trial with U.S. Army soldiers training to become combat medics. The purpose of this study is to determine if a 11-week, high intensity exercise program targeting the low back muscles using specialized equipment will result in a 25% increase in low back muscular strength and endurance compared with a lower intensity general core stability exercise.

Study Overview

• Status: Completed
• Conditions: Lower Back Injury
• Intervention / Treatment: Other: Lumbar ext. high intensity progressive resistance exercise; Other: Low intensity core stabilization exercise

Detailed Description

Background Low back injury is responsible for the largest percentage of non-battle injuries in the theater of operations and is a large contributor to non-expiration of active service attrition in the US Armed Forces. Weakness and poor endurance of the back muscles are associated with low back injury. Targeted, high intensity exercise approaches using specialized equipment to develop the strength and endurance of the "weak link" muscle group (the lumbar extensors) have been shown to reduce risk for low back injury in high-risk civilian workers, but have not been widely implemented in military settings.

Objective/Hypothesis Specific Aim: In a controlled clinical trial, the investigators will assess the effectiveness of a high intensity progressive resistance exercise training program targeting the lumbar extensors to improve lumbar extensor muscular strength and endurance in US Army soldiers.

Hypothesis: A high intensity progressive resistance exercise for the lumbar extensors will result in a 25% increase in lumbar extensor muscular strength and endurance compared with control following the 11-week intervention.

Study Design A mixed methods, two-arm, controlled clinical trial with cluster randomization will be conducted. The sampling frame will be soldiers training to become combat medics from one domestic US Army base. Soldiers will be randomly assigned (by platoon) to one of two interventions - experimental or control. All participants at a given platoon will receive the same intervention and all interventions will be carried out at the US Army base, in addition to the soldiers' usual physical fitness training program. Participants randomized to the experimental group (strengthening exercise) will perform lumbar extensor muscle progressive resistance exercise using standardized protocols. Exercise training will consist of 1 set of high intensity progressive resistance exercise for lumbar extensors on specialized equipment. Participants in the active comparator control group (stabilization exercise) will perform 5 minutes of low intensity core stabilization exercises on the floor. Interventions will be carried out 1X/week for 11 weeks. Outcome measures that will be utilized to test the hypothesis of Aim 1 include validated physical fitness tests for lumbar extension muscular strength and endurance. Fitness tests will be conducted at baseline and following the 11-week intervention period.

Relevance Soldiers preparing for deployment are in need of advanced technology to help improve and optimize the functional capacity of the lumbar extensor muscles. Assuming positive results from this study and confirmatory trials, implementation of this targeted exercise protocol will maximize resilience in soldiers at high risk for low back injury, thereby helping them become more physically fit to counteract the extreme physical demands required in combat.

• Study Type: Interventional
• Enrollment (Actual): 582
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Florida
    • Tampa, Florida, United States, 33612
      • University of South Florida
  • Texas
    • Fort Sam Houston, Texas, United States, 78234
      • Brooke Army Medical Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 35 years (ADULT)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Age 18-35 years
• Active duty soldiers in the US Army training to become combat medics at Fort Sam Houston

Exclusion Criteria:

• Cardiovascular contraindications to resistance exercise as identified by history and physical examination
• Orthopedic contraindications to resistance exercise as identified by history and physical examination
• History of systemic inflammatory disease or spinal surgery
• Low back pain intensity > "mild"
• Disability >= 50% on the Roland Morris Disability Questionnaire
• Currently receiving care for spinal pain disorder/injury
• Currently disabled due to spinal pain disorder/injury
• Currently diagnosed with or receiving treatment for a psychological or psychiatric disorder
• Currently performing progressive resistance exercises for the lumbar extensor muscles other than those included in standard for military fitness programs
• Active workers' compensation or personal injury case
• Pregnant
• Simultaneously enrolled in another biomedical clinical trial
• Drug or alcohol abuse within the past year
• Any other condition, which in the opinion of the investigators or military medical authority, would put the candidate at increased safety risk or otherwise make the candidate unsuitable for this study
• Unable or unwilling to complete the study procedures

Study Plan

How is the study designed?

Design Details

• Primary Purpose: PREVENTION
• Allocation: RANDOMIZED
• Interventional Model: PARALLEL
• Masking: SINGLE

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
EXPERIMENTAL: Strengthening Exercise; Lumbar ext. high intensity progressive resistance exercise	Other: Lumbar ext. high intensity progressive resistance exercise; 1 active set of 1 exercise, 1x/week, 11 weeks
ACTIVE_COMPARATOR: Stabilization Exercise; Low intensity core stabilization exercise	Other: Low intensity core stabilization exercise; 1 set of 5 exercises, 1x/week, 11 weeks

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Isometric Lumbar Extension Muscular Strength at 11 Weeks	Isometric lumbar extension muscular strength (torque - Nm) as assessed by a validated physical performance test on the lumbar dynamometer	11 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Isometric Core Muscular Endurance at 11 Weeks	Isometric core muscular endurance as assessed by a validated physical performance test (prone static plank test)	11 weeks
Dynamic Lumbar Extension Muscular Endurance at 11 Weeks	Dynamic lumbar extension muscular endurance (# repetitions at 50% peak torque) as assessed by a validated physical performance test on the lumbar dynamometer	11 weeks

Collaborators and Investigators

• Sponsor: University of South Florida
• Collaborators: Brooke Army Medical Center
• Investigators: Principal Investigator: William S Quillen, PT,DPT,PhD, University of South Florida; Study Director: John M Mayer, DC,PhD, University of South Florida

Publications and helpful links

General Publications

• Mayer JM, Childs JD, Neilson BD, Chen H, Koppenhaver SL, Quillen WS. Effect of Lumbar Progressive Resistance Exercise on Lumbar Muscular Strength and Core Muscular Endurance in Soldiers. Mil Med. 2016 Nov;181(11):e1615-e1622. doi: 10.7205/MILMED-D-15-00543.

Study record dates

Study Major Dates

• Study Start: June 1, 2012
• Primary Completion (ACTUAL): April 1, 2014
• Study Completion (ACTUAL): March 1, 2015

Study Registration Dates

• First Submitted: June 15, 2011
• First Submitted That Met QC Criteria: July 22, 2011
• First Posted (ESTIMATE): July 25, 2011

Study Record Updates

• Last Update Posted (ESTIMATE): May 25, 2015
• Last Update Submitted That Met QC Criteria: May 22, 2015
• Last Verified: May 1, 2015

More Information

Terms related to this study

• Keywords: low back muscular strength and endurance
• Additional Relevant MeSH Terms: Wounds and Injuries; Back Injuries
• Other Study ID Numbers: 10193004