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Trial registered on ANZCTR


Registration number
ACTRN12620001314910
Ethics application status
Approved
Date submitted
16/09/2020
Date registered
7/12/2020
Date last updated
7/12/2020
Date data sharing statement initially provided
7/12/2020
Type of registration
Retrospectively registered

Titles & IDs
Public title
Keeping cool and calm in the heat: The development of evidence-based recovery strategies for optimised performance and safety in operational firefighters
Scientific title
The effect of evidence-based recovery and cooling strategies on the core temperature of firefighters following stressful fire-fighting tasks in the heat
Secondary ID [1] 302330 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Healthy firefighters under heat stress 319099 0
Condition category
Condition code
Other 317053 317053 0 0
Research that is not of generic health relevance and not applicable to specific health categories listed above

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
This experiment will be a randomised control cross over trial. Participants will visit UTS Moore Park climate chamber on four separate occasions separated by at least one week. Participants will perform one of three separate conditions during each visit (control and two recovery protocols [basic and advanced cooling]) plus a familiarisation visit.

Protocol
The performance task will be representative of parts of structural, rescue and bushfire fire-fighting as these were the most demanding (physically and mentally) and hottest perceived tasks found in previous research, the most demanding critical task simulations highlighted in physical aptitude testing (PAT) previous research (Taylor et al. 2015a, Taylor et al., 2015b, Groeller et al. 2015, Fullagar et al., 2015) and will overall reflect current FRNSW operational procedures (e.g. firefighters are trained and familiar with these tasks and loads). Overall, this task will last approximately 20 minutes in total to replicate an average breathing apparatus wear which firefighters perform in the field. Firefighters will wear duty wear (standard undergarments), full personal protective clothing (PPC), breathing apparatus (BA), helmet and radio (total weight ~20 kg) as per normal FRNSW procedures. Task will involve:

Stressful firefighter task in the heat
2 min warm up walk on treadmill (5 km/h, no incline)
Loaded carry walk (5 km/h level; 26 kg black rock jerry can [water] using preferred hand; 1 min)
Step up task on blocks off treadmill (replicate stair climb [structural]; set cadence and step up w/ 17.5 kg load [water blue cap]; 4 min)
Car rescue task with tool. This task involves static hold of a 19.5 kg tool at three differing levels —knee, waist, and eye level (approx. duration 2 min 40 sec [rescue])
Bushfire replicated task – alternating minute on treadmill and minute off with battle rope whips/bands/hose (replicate bush walk/hose pull [bushfire]; 5 km/h at 3.5%; 10 min in total)
The climate chamber will be set and matched to mean max temperature and humidity for summer in the Sydney region to replicate likely firefighter conditions (~30-32oC, 60% humidity) and a normobaric (750 mmHg) environment. The simulated task will then be repeated (40 min in total [2 BA wears]; SOG, Incident Ground Rehabilitation FRNSW)), with mandatory “rehabilitation/recovery” periods in between each task as per standard firefighting and SOG procedures. Here, three separate conditions will be undertaken (control and two recovery protocols; each 20 minutes) outside the climate chamber in the UTS physiological laboratory. The conditions are:

CONTROL: Passive, seated rest with top layer of PPC/BA removed + 7 g·kg-1 BW (e.g. ~600 ml for an 85 kg person; Ihsan et al. 2010) ambient water [sealed bottle; 20oC; which contains a dissolved hypotonic solution (150 mOsmol·L-1) (Aqualyte, Point Health Pty Ltd., Australia)].

RECOVER-BASIC (R1): Remove top and bottom layer of clothing as per control + fans + CoolaTM chairs w/ ambient water [20oC] + wet towels [to be placed on head/upper back/neck; pulled from ambient water buckets; 20oC]) + 7 g·kg-1 BW cold water ingestion [sealed bottle from fridge; 13-15oC, which contains a dissolved hypotonic solution (150 mOsmol·L-1) (Aqualyte, Point Health Pty Ltd., Australia)]
Example timeline: TASK 1 – R1 – TASK 2 – R1

RECOVER-ADVANCED (R2): Remove top and bottom layer of clothing as per control + misting/cooling fans + CoolaTM chairs w/ iced water [13-15oC] + ice packs/towels [to be placed on head/upper back/neck; pulled from iced water buckets; 10-12oC] + ice slushy ingestion [7 g·kg-1 BW of crushed ice slush drink (–1 °C; Caress 1, CAB S.p.A, Italy), which contains a dissolved hypotonic solution (150 mOsmol·L-1) (Aqualyte, Point Health Pty Ltd., Australia)).

That is, there will be 20 minutes of pre-baseline measures, a 20 minute task, a 20 min recovery protocol, a 20 min task and a 20 min recovery protocol followed by post-measures. Four ESSA accredited exercise scientists will be supervising, and there will always be one of these personnel who is first aid trained. The experiment will be completed individually, with instruction and recording completed by the support personnel. There will be a minimum of a 5 day washout between sessions and a maximum of two weeks. The familiarisation will be a guided simulation of the activities to be undertaken during the assessment sessions but with actual completion of all performance measures.

Primary outcome measures will include:
• Pre-post nude body mass (kg)
• Core temperature (BodyCap core temperature pills, ToC). Core-temperature pills will be ingested at least 6-8 h before exercise. Core temperature will be recorded continuously (1-minute intervals) using a wireless data logger worn by the participants.
• Heart rate (Polar Systems; HR; beats per min) monitored continually through the protocol through a HR belt
• Blood pressure (Hg; automatic cuff; Omron)
• Rating of perceived exertion (RPE; arbitrary units)
• Grip strength (Handgrip dynamometer; N)
• Proprioception/balance (Balance Error Scoring System (BESS); score)
• Validated perceptual scales (thermal sensation, fatigue, task performance)
• Thermal sensation scale prior to and after performance. Thermal sensation will be evaluated using a subjective scale from 1 (extremely cold) to 13 (extremely hot), modified after Gagge et al. (1967), where the end points have been extended to enable a better resolution of thermal sensation. Participants will be asked: “How does the temperature of your body feel?”. Thermal discomfort will be assessed using a second scale (1= comfortable to 5= extremely uncomfortable), also modified after Gagge et al. (1967), and participants will respond to the question: “How comfortable do you feel with the temperature of your body?”
• Perceptual fatigue (1= no fatigue, 10 = fully fatigued; (Neuberger 2003)
• Task performance (Likert; 1 = extremely poor, 10 = extremely good)
• Gastrointestinal comfort (Likert 1 = no symptoms, 100 = extreme symptoms; Costa et al 2016)
• Perceptual-cognitive and -motor tasks
• Multiple object tracking task (sustained selective attention; task developed using the MOT paradigm, Pylyshyn & Storm, 1988) where participants are required to track a subset of identical items designated as target items, while all items move randomly and independently.
• Precued reaction time task. Finally, a precued reaction time paradigm (Beavan et al., 2019; Barela et al., 2019) will be used to assess firefighters ability to use or suppress congruent and incongruent information that is presented as a brief precue.
Intervention code [1] 318622 0
Treatment: Other
Comparator / control treatment
CONTROL: Passive, seated rest with top layer of clothing and breathing apparatus removed + 7 g·kg-1 BW (e.g. ~600 ml for an 85 kg person; Ihsan et al. 2010) ambient water [sealed bottle; 20oC; which contains a dissolved hypotonic solution (150 mOsmol·L-1) (Aqualyte, Point Health Pty Ltd., Australia)].

This is performed immediately following each firefighter task
Control group
Active

Outcomes
Primary outcome [1] 325150 0
Core temperature (BodyCap core temperature pills, ToC). Core-temperature pills will be ingested at least 8 h before exercise.
Timepoint [1] 325150 0
Core temperature will be recorded continuously (1-minute intervals) using a wireless data logger worn by the participants (approx 120 minutes).
Secondary outcome [1] 387005 0
Multiple object tracking task (sustained selective attention; task developed using the MOT paradigm, Pylyshyn & Storm, 1988) where participants are required to track a subset of identical items designated as target items, while all items move randomly and independently.
Timepoint [1] 387005 0
Pre and post trial for each of three sessions
Secondary outcome [2] 387006 0
Perceptual scales (thermal sensation)
• Thermal sensation scale prior to and after performance. Thermal sensation will be evaluated using a subjective scale from 1 (extremely cold) to 13 (extremely hot), modified after Gagge et al. (1967), where the end points have been extended to enable a better resolution of thermal sensation. Participants will be asked: “How does the temperature of your body feel?”. Thermal discomfort will be assessed using a second scale (1= comfortable to 5= extremely uncomfortable), also modified after Gagge et al. (1967), and participants will respond to the question: “How comfortable do you feel with the temperature of your body?”
Timepoint [2] 387006 0
Pre and post trial for each of three sessions
Secondary outcome [3] 387007 0
Grip strength (Handgrip dynamometer)
Timepoint [3] 387007 0
Pre and post trial for each of three sessions
Secondary outcome [4] 387008 0
• Proprioception/balance (Balance Error Scoring System (BESS); score)
Timepoint [4] 387008 0
Pre and post trial for each of three sessions
Secondary outcome [5] 387009 0
Heart rate, blood pressure (Hg; automatic cuff; Omron)
Timepoint [5] 387009 0
Continuous data monitored (30 sec intervals) for approx 120 minutes across all sessions
Secondary outcome [6] 388586 0
Precued reaction time task. Finally, a precued reaction time paradigm (Beavan et al., 2019; Barela et al., 2019) will be used to assess firefighters ability to use or suppress congruent and incongruent information that is presented as a brief precue. This reflects firefighters’ abilities to use implicit sources of information to inform action.
Timepoint [6] 388586 0
Pre and post trial for each of three sessions
Secondary outcome [7] 388587 0
Perceptual fatigue (1= no fatigue, 10 = fully fatigued; (Neuberger 2003)
Timepoint [7] 388587 0
Every 5 minutes during each session
Secondary outcome [8] 388588 0
• Task performance (Likert; 1 = extremely poor, 10 = extremely good)
Timepoint [8] 388588 0
Every 5 minutes during each session
Secondary outcome [9] 388589 0
• Gastrointestinal comfort (Likert 1 = no symptoms, 100 = extreme symptoms; Costa et al 2016)
Timepoint [9] 388589 0
Every 5 minutes during each session
Secondary outcome [10] 388590 0
Rating of perceived exertion (RPE 6-20)
Timepoint [10] 388590 0
Every 5 minutes during each session

Eligibility
Key inclusion criteria
The selection pool of participants are all firefighters employed by FRNSW. To be considered healthy, participants cannot be current or recent (<6 months) smokers, and those with any history of cardiovascular, renal, musculoskeletal, or metabolic diseases will be excluded. Health history will be collected using questionnaires (American College of Sports Medicine Pre-Participation Screening) to assess for eligibility. To be included, and ensure completion of the exercise protocol, participants must be physically active, which is defined, in accordance with ACSM, as regularly engaging in a minimum of 30 minutes of moderate intensity aerobic activity at least 3 days a week. Participants will also complete a Par-Q Questionnaire to prove their health (no risks to cardiovascular health, heat illness or other contraindications). Further, since core temperature will be monitored using a telemetry pill, participants will complete a screening form, and any participant with contraindications to telemetry pill use will be excluded from the study.
- Sex: M/F
- Age range: 18-65y
- Weight: any
- Height: any
- Willingness to give written consent willingness to participate to and comply with the study.
Minimum age
18 Years
Maximum age
65 Years
Sex
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
Those not in the inclusion criteria.
- Participants with a history of a psychological illness or condition such as to interfere with the Participant's ability to understand the requirements of the study.
- Participants with a diagnosed injury that is likely to interfere with the evaluation of the Participant's safety and of the study outcome.

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Central randomisation by computer
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Simple randomisation using a randomisation table created by computer software
Masking / blinding
Open (masking not used)
Who is / are masked / blinded?



Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint/s
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
11/11/2020
Date of last participant enrolment
Anticipated
15/01/2021
Actual
Date of last data collection
Anticipated
28/02/2021
Actual
Sample size
Target
17
Accrual to date
5
Final
Recruitment in Australia
Recruitment state(s)
NSW

Funding & Sponsors
Funding source category [1] 306761 0
University
Name [1] 306761 0
Early Career Research Seed Funding Award
Country [1] 306761 0
Australia
Primary sponsor type
University
Name
University of Technology Sydney
Address
University of Technology Sydney, Moore Park Rd & Driver Ave,
Moore Park, NSW 2021, Australia
Country
Australia
Secondary sponsor category [1] 307313 0
None
Name [1] 307313 0
Address [1] 307313 0
Country [1] 307313 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 306925 0
University of Technology Human Research Ethics Committee
Ethics committee address [1] 306925 0
Ethics committee country [1] 306925 0
Australia
Date submitted for ethics approval [1] 306925 0
Approval date [1] 306925 0
30/03/2020
Ethics approval number [1] 306925 0
ETH20-4578

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 105470 0
Dr HUGH FULLAGAR
Address 105470 0
UTS Sport and Exercise Science
PO Box 123 Broadway NSW 2007 Australia
Country 105470 0
Australia
Phone 105470 0
+61295145240
Fax 105470 0
Email 105470 0
Hugh.Fullagar@uts.edu.au
Contact person for public queries
Name 105471 0
HUGH FULLAGAR
Address 105471 0
UTS Sport and Exercise Science
Moore Park precinct
PO Box 123 Broadway NSW 2007 Australia
Country 105471 0
Australia
Phone 105471 0
+61295145240
Fax 105471 0
Email 105471 0
Hugh.Fullagar@uts.edu.au
Contact person for scientific queries
Name 105472 0
HUGH FULLAGAR
Address 105472 0
UTS Sport and Exercise Science
Moore Park precinct
PO Box 123 Broadway NSW 2007 Australia
Country 105472 0
Australia
Phone 105472 0
+61295145240
Fax 105472 0
Email 105472 0
Hugh.Fullagar@uts.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.