Feasibility of a Train-the-Trainer Delivered Exercise Intervention in Firefighters

Study Overview
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Brief Summary
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Purpose: To collect and report feasibility data for conducting a future cluster randomized trial to evaluate the efficacy of a TRAINER delivered integrated exercise program in career firefighters, and to determine intervention fidelity and preliminary effects of a TRAINER delivered integrated exercise program in career firefighters. Participants: 52 career firefighters 18 - 60 years old (40 trainees, 6 trainers, 6 administrators). Procedures (methods): Enrolled fire stations will be randomly assigned (3:2 allocation ratio) to a TRAINER or wait-list control (CON) group, stratified by city, using computer-generated random numbers. All enrolled firefighters will undergo a series of assessments at baseline (week 0) and post-testing (week 7) following the TRAINER delivered 6-week intervention.

Official Title
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Feasibility of a Train-the-Trainer Delivered Exercise Intervention in Firefighters

Conditions
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Firefighter, High Intensity Interval Training

Intervention / Treatment
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* Behavioral: Integrated Exercise Program


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Provide informed consent prior to any study procedures are performed Medically cleared for fire suppression duties A career firefighter from a local department (Carrboro, Chapel Hill, and Durham) Exclusion Criteria: Highly active firefighters, defined as performing 4 or more days/week of vigorous exercise Pregnancy Recent injury preventing their participation in the exercise routine Involved in an active workers' compensation or personal injury case

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Two group design where 40 firefighters are cluster randomized (3:2 ratio) into a TRAINER or waitlist control group. There will be 6 trainers who will lead the TRAINER condition. All participants in the TRAINER group and following the intervention in the waitlist control group will receive the same integrated exercise program, led by a peer-trainer, including a neuromuscular warm-up and high intensity interval training at their respective fire stations 2 times per week for 6 weeks.
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: TRAINER<br>The TRAINER group will receive an integrated exercise program, led by a peer-trainer, including a neuromuscular warm-up and high intensity interval training at their respective fire stations 2 times per week for 6 weeks. | Behavioral: Integrated Exercise Program<br>* Neuromuscular warm-up: Each participant will perform a series of dynamic stretches, core stability, balance, and medicine ball exercises. The dynamic stretches include 8 repetitions of 6 stretches targeting the hip and thigh musculature, followed by 3 core stability isometric exercises (curl-up, side bridge, and bird dog). Participants will then perform 2 sets (per leg) of hop-to-stabilization (with a reach) balance exercises, followed by 3 separate medicine ball exercises emphasizing explosive full-body movements. High Intensity Interval Training (HIIT): HIIT will include a series of high intensity exercise bouts on a stationary bike that includes a 1:1 work-to-rest ratio. Training intensity will be determined from the peak power output obtained during the baseline VO2 peak assessment and progressively increased by the number of bouts and intensity. The number of work bouts will increase from 5 to 8 bouts and the intensity will increase from 90 to 110% of peak power output.<br>* Other names: HIIT;|
| No Intervention: Waitlist Control<br>The waitlist control group will not receive training during the course of the study, but will be offered the opportunity to receive the integrated exercise program after the study ends. | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Firefighters and Fire Stations Recruited to the Study (Feasibility) | To demonstrate the feasibility of an integrated exercise program. Feasibility will be defined as recruitment of 40 firefighters and the number of fire stations (out of 26 potential) to the study within 14 months. | Within 14 months | 
| Percentage of Firefighters Retained (Feasibility) | To demonstrate the feasibility of an integrated exercise program. Retention will be determined from the percentage of firefighters retained at post-testing. Retention of 80% or higher will be considered good feasibility. | Week 7 (post-intervention) | 
| Percentage of Sessions Attended (Feasibility) | To demonstrate the feasibility of an integrated exercise program. Adherence will be determined from the percentage of sessions attended out of total (12) sessions. Adherence of 80% or higher will be considered good feasibility. | Week 7 (post-intervention) | 
| Qualitative Summaries of Participant Experience in Semi-Structured Interviews (Acceptability) | Acceptability will be assessed by semi-structured interviews with the firefighters, peer-trainers, and departmental administration (e.g. fire chiefs). Qualitative summaries for intrapersonal, interpersonal, and organizational constructs will be reported. | Week 7 (post-intervention) | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change in cardiorespiratory fitness as measured by VO2 peak during cycle ergometry | Cardiorespiratory fitness will be measured by peak oxygen consumption (VO2 peak). All participants will perform a cycling ergometer test with respiratory gases continuously monitored with open-circuit spirometry (True One 2400®, Parvo-Medics, Inc., Provo, UT). Data will be averaged over 15-second intervals, with the highest 15-second oxygen consumption recorded as the VO2 peak. | Baseline (i.e., pre-intervention), 7 weeks (i.e., post-intervention) | 
| Change in body composition as measured by % body fat from a 4-compartment model | Body composition will be evaluated to determine the effects of the intervention on % body fat. Dual-energy x-ray absorptiometry (DXA;General Electric Lunar iDXA, Chicago, IL) and bioelectrical impedance spectroscopy (BIS; ImpediMed SFB7, Queensland, AU) will be used to determine a gold-standard DXA-derived four-compartment model of % body fat. | Baseline (i.e., pre-intervention), 7 weeks (i.e., post-intervention) | 
| Change in explosive muscle strength as measured by dynamometry | All participants will perform a rapid and maximal isometric muscle action on a calibrated isokinetic dynamometer (CSMi, Stoughton, MA) against a padded and stiff lever arm for 3-4 seconds. The peak rate of torque development will be determined from the peak of the first derivative of the torque-time curve. | Baseline (i.e., pre-intervention), 7 weeks (i.e., post-intervention) | 
| Change in low-back muscular endurance as measured by a modified Biering-Sorensen test | Low-back muscular endurance (time to task failure) will be examined using a modified version of the Biering-Sorensen test, using a variable angle Roman chair (Powerlift, Jefferson, IA). | Baseline (i.e., pre-intervention), 7 weeks (i.e., post-intervention) | 
| Change in balance as measured by a modified star excursion balance test | Balance will be determined by using a modified star excursion balance test. Following a familiarization, participants will reach with their free limb as far as possible in the anterior, posterolateral, and posteromedial direction relative to the stance leg. Scores will be normalized to leg length. | Baseline (i.e., pre-intervention), 7 weeks (i.e., post-intervention) | 
| Fidelity of the neuromuscular warm-up as measured by a rubric across sessions at Week 2 | The fidelity of the neuromuscular warm-up will be examined using a scoring rubric. The rubric evaluates the leadership abilities of the trainers and the execution of the exercises by the firefighters. Each item is scored 1 to 5 with 1 indicating no correctness and 5 indicating complete correctness. Items will be summed for a total score. Higher values mean higher fidelity. | 2 weeks (i.e., beginning of intervention following train-the-trainer completion) | 
| Fidelity of the neuromuscular warm-up as measured by a rubric across sessions at Week 6 | The fidelity of the neuromuscular warm-up will be examined using a scoring rubric. The rubric evaluates the leadership abilities of the trainers and the execution of the exercises by the firefighters. Each item is scored 1 to 5 with 1 indicating no correctness and 5 indicating complete correctness. Items will be summed for a total score. Higher values mean higher fidelity. | 6 weeks (i.e., one of last 2 sessions) | 
| Fidelity of the HIIT protocol as measured by rate of peak power output across sessions at Week 2 | Fidelity will be assessed to ensure participant adherence to the intervention protocol in each session. The fidelity of the HIIT protocol will be examined by recording the prescribed peak power output (90-110%) during the training session. Training intensity will be established from a percentage of the baseline peak power output (Watts) achieved during the VO2 peak test. Higher fidelity is indicated as the percent power output more closely approaches the prescribed power output percentage. | 2 weeks (i.e., beginning of intervention following train-the-trainer completion) | 
| Fidelity of the HIIT protocol as measured by rate of peak power output across sessions at Week 6 | Fidelity will be assessed to ensure participant adherence to the intervention protocol in each session. The fidelity of the HIIT protocol will be examined by recording the prescribed peak power output (90-110%) during the training session. Training intensity will be established from a percentage of the baseline peak power output (Watts) achieved during the VO2 peak test. Higher fidelity is indicated as the percent power output more closely approaches the prescribed power output percentage. | 6 weeks (i.e., one of last 2 sessions) | 
| Change in physical activity as measured by the International Physical Activity Questionnaire-Short Form | Physical activity will be examined using the validated 7-day recall International Physical Activity Questionnaire-Short Form. Higher scores represent greater total metabolic equivalent of task (MET) minutes of physical activity per week based on the following estimates: 3.3 MET units for walking, 4.4 MET units for moderate activity, 8 MET units for vigorous activity. Total MET minutes of physical activity is calculated from the questionnaire using the following calculation: Total MET-min/week = (Walk METs*min*days) + (Mod METs*min*days) + Vig METs*min*days) The study will test whether there is a BASELINE-to-POST increase in total scores on the International Physical Activity Questionnaire-Short Form (units: MET minutes/week) for the TRAINER group relative to the waitlist control group. The outcome for each group is computed as the main of the difference of the POST score minus the BASELINE score. | Baseline (i.e., pre-intervention), 7 weeks (i.e., post-intervention) | 
| Change in nutrition as measured by the Rapid Eating Assessment for Participants-Short Form | Nutritional habits will be examined using the validated Rapid Eating Assessment for Participants-Short Form. Responses of 'usually/often' receives 1 point, 'sometimes' receives 2 points, and 'rarely/never or does not apply to me' receives 3 points. Possible scores ranged from 13 to 39 with a higher score indicating better nutritional habits. The study will test whether there is a BASELINE-to-POST increase in total scores on the Rapid Eating Assessment for Participants-Short Form for the TRAINER group relative to the waitlist control group. The outcome for each group is computed as the main of the difference of the POST score minus the BASELINE score. | Baseline (i.e., pre-intervention), 7 weeks (i.e., post-intervention) | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Firefighter, Train-the-Trainer, High intensity interval training, Neuromuscular warm-up, Fire and Rescue Personnel