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

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.

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.

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.

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.

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.

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.

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.

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).

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.

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.

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.

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.

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.

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.

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.