This study examined the effects of firefighter self-contained breathing apparatus (SCBA) design, exercise duration, and load carriage on gait parameters related to fall risk. Thirty firefighters completed various exercise protocols while wearing SCBAs of different sizes. Heavier SCBAs and longer exercise duration were found to cause more conservative gaits that may indicate fatigue, a risk factor for slips, trips and falls. However, a prototype low-profile SCBA design did not significantly affect gait. Additional bouts of exercise further changed gait, but breaks did not reduce these changes, suggesting greater muscular fatigue.

1. Faith F. Bradley1 , Grace S. Deetjen1, Michael J. Angelini2, Richard M. Kesler3, Matthew N. Petrucci4,
Karl S. Rosengren5, Gavin P. Horn2,3, and Elizabeth T. Hsiao-Wecksler1,2
Exercise and Load Carriage Can Affect Firefighter Gait
1Dept. of Bioengineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
2 Dept. of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, IL, USA
3Illinois Fire Service Institute, University of Illinois at Urbana-Champaign, Champaign, IL, USA
4Neuroscience Program, University of Illinois at Urbana-Champaign, Urbana, IL, USA
5Dept. of Psychology, Northwestern University, Evanston, IL, USA
Introduction
• Slip, trip, and fall (STF) injuries account for over 11,000 fireground injuries
every year [1].
• Changes to gait have previously been associated with dynamic instability,
loss of control of gait, and muscular fatigue [2,3]. Muscular fatigue has
been suggested to be an indicator of risk of STF injuries [4].
• This study quantified the effects of firefighter self-contained breathing
apparatus (SCBA) design and duration of firefighting activities on gait
parameters that may indicate risk for STF-related incidents.
Comparisons
Exercise
Condition
Rounds
Bout of
exercise
1R 1
2R 2*
BB 2**
*5 minute rehabilitation
break between bouts
outside chamber
**No break
Subjects completed 7 sessions with different combinations of SCBA and
exercise durations.
Four comparisons testing:
1. SCBA size
2. Exercise
3. Profile
4. SCBA size * Exercise
P45
SCBA
Standard Cylinders
Larger bottles supply more air but
weigh more and create a larger
displacement of the center of mass.
Low-Profile Prototype
Designed to reduce
displacement of center of
mass. Comparable weight
to S60 and comparable
volume to S45.
S30 S45 S60
30-minute 45-minute 60-minute
P45
Firefighting-Simulating
Exercise
Stair ascent and
decent
Hose advance
Room search Ceiling pull
• Exercise completed in environmental
chamber (47oC; 20% humidity, lights
off)
• 1 Bout of exercise = 2 minutes each
activity with 2 minutes rest between
activities
P45_1RS45_1R
S60_BB
S60_2RS30_2R
S30_1R S60_1R
Methods
Subjects
• 30 Firefighters (29 male, 1 female)
• Age: 30.7±8.1 years
• Height: 1.82±0.1 meters
• Weight: 91.2±15.4 kilograms
Session Agenda
Gait Assessment (PRE)  Exercise Protocol  Gait Assessment (POST)
Gait Analysis
Results and Discussion
SCBA Size
Multivariate ANOVAs were performed with SPSS (IBM, Armonk, NY) with
significance levels of α=0.05 for all analyses. Values were averaged from two PRE
and POST trials.
Results and Discussion (continued)
• Increased weight of SCBA increases DT.
• Changes to double-support time suggests the S30 affects gait significantly less
than the S45 or S60.
• Data represents average of PRE and POST. Error bars indicate standard error.
• (*) indicates significant differences from S30_1R (p<0.05).
Conclusion
• Heavier SCBA and extended duration of exercise may cause
firefighters to adopt more conservative gait, while profile appears to
have no effect. These gait changes may serve as a compensatory
strategy.
• The measured changes in gait may also indicate muscular fatigue,
which has been previously suggested to be associated with an
increased risk of STF injuries [3,4].
Future Work
• Examine leg length, level of fitness and years of experience
interaction with SCBA and exercise duration on firefighter gait.
• Examine if longer breaks will significantly reduce gait changes
resulting from fatigue.
• Some firefighters were not able to complete each 2R or BB exercise
protocol. These data may be separated from those who fully
completed all 8 sessions.
• All 4 gait parameters change as a result of an additional bout of
exercise.
• No effects on gait parameters as a result of a rehabilitation break.
• Reduced gait performance following an additional bout of exercise
may indicate greater muscular fatigue.
• (*) indicates significant differences from S60_1R (p<0.05).
• Data represents the average of PRE and POST values. Error bars
indicate standard error.
Exercise
Profile
• No effects on gait with the low-profile prototype.
SCBA Size * Exercise
• No significant interaction between the SCBA size and exercise.
Double-Support time
(DT) = time both feet
contact ground
Four parameters of gait were assessed using a
gait mat (GAITRite, 29 foot Platinum, CIR
Systems; Sparta, NJ):
(1) stride velocity (SV)
(2) stride length(SL), (3) step width (SW)
and (4) double-support time (DT).
7.92 m
[1] M. J. Karter, Patterns of Firefighter Fireground Injuries, Quincy, Massachusetts: National Fire
Protection Association, 2003.
[2] Barbieri, Fabio Augusto, et al. "Systematic review of the effects of fatigue on spatiotemporal
gait parameters," Journal of back and musculoskeletal rehabilitation, 2013, 125-131.
[3] Barbieri, Fabio Augusto, et al. "Effect of muscle fatigue and physical activity level in motor
control of the gait of young adults." Gait & posture, 2013, 702-707.
[4] Parijat, Prakriti, and Thurmon E. Lockhart. "Effects of lower extremity muscle fatigue on the
outcomes of slip-induced falls." Ergonomics, 2008, 1873-1884.
References
Acknowledgements
This project was funded through the DHS grant (#EMW-2010-FP-01606).