Submitted to:
Mr. Ray Richards, MBA, Director (Fire Chief) Fire & Disaster Services
Station #3 – Headquarters – 100 Giroux Road St. Albert, Albert, Canada
and
Mr. Casey Danford, President and CEO Training Mask, LLC
1140 Plett Rd
Cadillac, Michigan, USA
Submitted by:
Randy W. Dreger, PhD, CSCS, CSEP CEP Scott Paradis, CSEP CPT
Personal Fitness o2 trainer 2.0 Program, School of Health Sciences Northern Alberta Institute of Technology
March 7, 2013
EXECUTIVE SUMMARY
The physical demands of firefighting have been well documented in the scientific literature. The protective equipment necessary for the firefighter to do their job has been shown to negatively impact work ability. The weight and heat stress associated with the equipment is a major factor. In addition, the self contained breathing apparatus (SCBA) has been shown to be a significant limiter to performance.
Various strategies have been used to alleviate the impact of the SCBA including design modifications, enriched oxygen mixtures and physical training programs. The most cost effective method of counteracting the negative effect of the SCBA has been high intensity interval training while wearing the SCBA; in essence, a form of resistive breathing while exercising. However, the cost of an SCBA along with the cost of refilling the air cylinders could be cost prohibitive to small departments.
On the market are a number of resistive breathing devices that are typically used in a sitting position at rest, which is very different from the demands of firefighting. Recently, the development of a resistive breathing device that was designed to be used during exercise has become commercially available – the Elevation Training Mask (ETM). The ETM primarily provides an adjustable resistance during inspiration with a set resistance on expiration.
The current investigation set out to determine the effect the ETM had on indicators of performance. A training study of high intensity interval training (HIIT) was employed while wearing the ETM. Participants (8 males and 6 females) were pre and post tested on measures of pulmonary and cardiac function. The training consisted to cycle ergometry, 2 times per week for 5 weeks. Intensity was set at a load equivalent to a percentage of maximal oxygen consumption (VO2max) and was adjusted in a periodized model.
The response to the HIIT training while wearing the ETM showed an improvement in the primary variables of power output and VO2max in the Rudolph valve maximal test condition. The males showed significant improvements in VO2max (8.3%) and power output (9.8%) whereas; the females were 4.6% and 8.3% respectively (not significant). These findings were similar to previous investigation of HIIT training while wearing the SCBA (Dreger and Paradis, 2011; Paradis and Dreger, 2011).
The underlying physiological mechanisms for the improvements in VO2max and power output were related to increases in ventilator ability for both males and females (VE increased by approximately 9% in both groups [p<0.05]). In addition, cardiac function as described by O2 pulse, which is a surrogate for stroke volume, increased for both males and females 10% and 6.8%, respectively.
During the training sessions heart rate responses were measured at the end of each work and relief interval. The heart rate responses in the last work interval during the first and last training sessions were substantially lower for the males (180 vs. 176 beats•min-1) and females (180 vs. 173 beats•min-1). When averaged over the entire training session, there was a significant reduction in total heart rate responses from the first to last session. Further supporting the improved cardiopulmonary changes noted during the maximal testing.
The results of this study demonstrated that HIIT while wearing the Elevation Training Mask significantly improved selected variables for males and females. The males tended to have more variables significantly improve than females. These findings are similar to previous study using the same training protocols, but wearing the SCBA; thus, implying that the Elevation Training Mask is equally effective as the SCBA during HITT. It is suggested that further study of the female participants are required to determine the reasons why they do not respond to the training as their male counterparts.
ACKNOWLEDGMENTS AND DISCLAIMERS
- The authors would like to thank the many volunteers that participated in this study. With out their participation this project could not have been completed.
- Elevation Training Masks were provided by Training Mask, LLC to perform this study.
- City of St. Albert Fire Department provided air cylinder filling for this project.
- Financial support was provided in part by Alberta Innovates Product Development Program grant.
- Financial support was provided in part by novaNAIT Applied Research grant.
- SCBA and Training Mask pressure testing was provided by Acklands-Grainger Inc, Edmontn, Alberta.
BACKGROUND
Firefighting is considered to be one of the most physically demanding and hazardous civilian occupations (Gledhill and Jamnik 1992a, b; Guidotti and Clough, 1992). Lusa et al. (1994) determined that regardless of age or rank, one of the most physically demanding tasks faced by firefighters is that of smoke-diving (search and rescue). This task typically involves entry into a dark, smoke-filled structure where the firefighter must search, by feel, for casualties and then evacuate them to safety. Research has shown that search and rescue work during actual fire emergencies elicits near-maximal heart rate responses (Sothmann et al., 1992) and places a significant demand on the aerobic system (Gledhill and Jamnik, 1992a; Bilzon et al., 2001).
Due to the environmental hazards the firefighter faces, they are required to wear personal protective equipment (PPE) and a self-contained breathing apparatus (SCBA). Previous investigations have assessed the effect of the SCBA (Eves et al., 2005), PPE (Louhevaara et al., 1995) and the combined effects of SCBA and PPE (Dreger et al., 2006; 2009) on working capacity. This research has shown that the SCBA has a negative impact on an individual’s working capacity (VO2max). Dreger et al. (2006) showed a 17% decrease in VO2max when encumbered in the PPE and SCBA. The cause of this decrease has been associated with a decrease in exercising lung function (ventilation) and heart function (Dreger et al., 2006; 2009; Nelson et al., 2009).
The negative impact the SCBA has on VO2max; researchers have studied various methods to alleviate this problem. One means of improving VO2max is through high intensity interval training (HIIT) (Gormley et al., 2008; Wisloff et al., 2009). Changes in both lung and cardiac function have been associated with the improvements in VO2max (Helgerud et al., 2007). Recently, Dreger and Paradis (2011) and Paradis and Dreger (2011) reported the effect of HIIT while breathing from an SCBA. Their study showed significant improvements in performance, pulmonary and cardiovascular function that was significantly greater than HIIT training without the SCBA. However, the cost of an SCBA is approximately $3,500 with air supply being an additional “disposable” cost. This may be cost prohibitive to for smaller fire departments and those preparing to go into the fire trade. On the market there are a number of devices that restrict breathing, however many of them are used during sitting and not during exercise. Recently, a device has been developed to be used during exercise (Training Mask LLC, Cadillac, MI). The Elevation Training Mask provides variable breathing resistance, which may simulate the SCBA. However, there has not been any scientific study of the ETM nor its effects relative to the SCBA. The purpose of this investigation was to examine the effect of the Elevation Training Mask while performing HIIT.
NAIT UNIVERSITY RESEARCH DESIGN
A two phase approach was undertaken in this project. The first phase involved prototyping and fitting the ETM (Figures 1 and 2) and the SCBA (Figures 3 and 4) with a custom made “cone” to collect expired air while the subjects were exercising.
Figure 1. Custom cone for ETM
Figure 2. ETM with custom cone attached
Figure 3. Custom cone for SCBA
Figure 4. SCBA with custom cone attached
The SCBA and the ETM were then tested to determine the resistance of the devices with the custom made cones.
Figure 5 shows the testing device (PosiCheck3, Sophia, WV) utilized to determine the mask pressure of the ETM and the SCBA.
Testing was performed by a certified technician at an accredited testing center (Acklands- Grainger Inc, Edmonton, Alberta).
Figure 5. PosiCheck3 pressure testing device with ETM and custom cone attached.
The second phase involved recruiting subjects to participate in the research study and then undergo a battery of pre-testing, supervised training program, and post-testing followed by data analysis and report writing.
Experimental Overview
Each subject underwent the following; informed consent; screening via rPAR-Q and Physical Activity Index; pulmonary function test; orientation; three VO2max tests (Rudolph valve, SCBA and ETM condition); a 5-week intensive aerobic training program using the Training Mask; post training pulmonary function test and VO2max tests. Screening Each participant provided written informed consent to participate in the project, which was approved by the NAIT Research Ethics Board (Appendix A). Upon consent, each subject completed a Physical Activity Index (PAI, Appendix B) and Revised Physical Activity Readiness Questionnaire (rPAR-Q, Appendix C) that was designed to identify those individuals for whom vigorous exercise may be inappropriate. Depending on the answers to these questionnaires participants may have become ineligible for entry into the study.
Orientation
The orientation session provided subjects the opportunity to become familiar with the SCBA and ETM, maximal testing and high intensity training. At this session subjects performed pulmonary function tests along with measures of height, weight, and body composition. In addition, they performed an abbreviated exercise bout wearing the SCBA and the ETM.
Anthropometry and Body Composition
Measures of height and weight were taken for each of the subjects and recorded to the nearest 0.5 centimeter and 0.1 kilogram, respectively (CSEP, 2006). Body composition was determined via bioelectrical impedance (BIA) using a hand-held BIA device (Model HBF-306CAN, OMRON, Burlington, ON).
Pulmonary Function Testing (PFT)
During the orientation session and prior to the last VO2max testing session
subjects performed a standard spirometry test (Ruppel, 2009). Subjects sat quietly while breathing through a hand-held screen-pneumotach (#113183, Hans Rudolph, Inc. Kansas City, MO) while wearing a soft nose clip (Figure 6). Subjects were asked to take as deep a breath as possible, and then exhale into the sensor as hard as possible, for as long as
possible. They performed this maneuver two or three times with the best result recorded for the study.
Figure 6. Subject performing spriometry and MVV with hand-held pneumotach.
Maximum Voluntary Ventilation (MVV): Subjects performed a standard MVV (Ruppel, 2009). Subjects sat quietly while breathing through a hand-held screen- pneumotach (#113183, Hans Rudolph, Inc. Kansas City, MO) while wearing a soft nose clip were asked to breathe as deep a and as quickly as possible for a 15-second interval (Figure 6).
VO2max Testing
Maximal Oxygen Consumption (VO2max) test: Subjects rode a cycle ergometer (Velotron Dynafit Pro, RaceMate Inc., Seattle, WA) for the exercise mode. The first phase involved 2 minutes sitting quietly. Subjects then peddle at a self selected rate, with the initial intensity set at 25 Watts with an increase of 25 Watts per minute until volitional exhaustion. During the VO2max test subjects were dressed in athletic shorts, t-shirt and running shoes. They were either breathing through a low resistant valve (Hans Rudolf
2700 series, Shawnee, KS – Figure 7), the SCBA system (Eves et al., 2005 – Figure 8) or Training Mask (Figure 9), which was attached to a metabolic measurement system (TrueOne 2400, ParvoMedics, UT).
Figure 7. Subject performing VO2max test with Rudolph valve condition.
Figure 8. Subject performing VO2max test with SCBA condition.
Figure 9. Subject performing VO2max test with ETM condition.
Training Program
The training program had the subjects wear the ETM (Figure 10) while performing 2 training sessions per week for 5 consecutive weeks. While riding a cycle ergometer (Ergomedic 828E, Monark LTD., Vansbro, Sweden), subject performed a 5 minute warm- up, 2 minute work interval at an intensity equivalent to 90% of VO2max, 3 min relief interval at an intensity equivalent to 30% of VO2max based on the results from the ETM VO2max condition (Figure 9) repeated 5 times, and a 5 to 10 minute cool down (Gormley et al., 2008; Helgerud et al., 2007). When heart rate has returned to below 100 beats per minute subjects were considered “cooled down”. Each session was performed under the supervision of a qualified Personal Fitness Trainer. Table 1 describes the periodized training program used throughout the study.
| Table 1. Periodized training program | |||||
| Week | Sessions/wk | Work Time | Work Intensity | Relief Time | Relief Intensity |
| 1 | 2 | 2 min | 90% | 3 min | |
| 2 | 2 | 2 min | 90% | 3 min | |
| 3 | 2 | 2 min | 95% | 3 min | |
| 4 | 2 | 2 min | 100% | 3 min | |
| 5 | 2 | 2 min | 90% | 3 min | |
Figure 10. Subject performing a training session while wearing the ETM.
Statistics
Standard descriptive statistics of mean and standard deviation were used to describe the data. A paired t-test was used to determine a main effect between group means. A probability value of 0.05 was used to determine significance.
Results and Discussion Pressure Testing
Prior to sale, all SCBA are pressure tested with the same or similar system as described earlier (Figure 5). After the cone was attached to the SCBA (Figure 4) the unit was retested by a qualified technician to determine if there were any functional changes. There were no significant differences between the manufacture and retesting results (maximum pressure 5 cm H2O). During the assessment of the ETM, the pressures generated were beyond the capacity of the testing device (greater than 20 cm H2O) thus causing an automatic shut down. Due to the pressures generated with the ETM, it was determined that the standard (yellow) inspiratory resistance be used on the ETM (Figure 2) during all the testing and training sessions.
Subject Characteristics
Eight male and 6 female participants completed all the testing and training. Both the males and females were of average height and weight (Hoffman, 2006). The females had a normal BMI and percent body fat values; whereas the males BMI would be considered pre obese, however, their body fat percentage suggested that a large portion of their weight was due to muscle mass (Table 2).
| Table 2. Subject characteristics | ||||
| Males | Females | |||
| Variable | Mean | ±SD | Mean | ±SD |
| Age | ||||
| Height (cm) | ||||
| Weight (kg) | ||||
| BMI (kg/m2) | ||||
| Body Fat (%) | ||||
BMI = body mass index. SD = Standard Deviation
Training Responses
During the training sessions, heart rate responses were recorded during the work and rest intervals. Figures 11 and 12 depict the average heart rate responses for the male and female subjects during the first training session and the last training session. The exact same workload was applied in each condition. When the heart rates were averaged for the entire training session there was significant reduction post training for both the males (155 vs. 149 beats•min-1) and females (153 vs. 147 beats•min-1).
Figure 11. Average, male heart rate responses during the first training session (pre training) and the last training (post training) session.
Figure 12. Average, female heart rate responses during the first training session (pre training) and the last training (post training) session.
Power Output
On a cycle ergometer performance is described via power output. The change in power output pre to post testing was significantly improved for the males with a 9 to 12% change (Table 3). The females had improvements from 4.5 to 9.4%, but this did not reach significant change in performance.
| Table 3. Power output (watts – W) pre and post test during the various testingconditions (mean ± standard deviation) | ||||||
| Condition | Males | Females | ||||
| Pre | Post | Pre | Post | |||
| RV | 294 ± 29 | 325 ± 42* | 233 ± 44 | |||
| SCBA | 281 ± 42 | 309 ± 35* | 225 ± 42 | |||
| ETM | 265 ± 33 | 303 ± 31* | 204 ± 29 | |||
*= significant difference from pretesting (p<0.05). RV = Rudolph valve condition. SCBA = self contained breathing apparatus condition. ETM = Elevation Training Mask condition.
Maximal Oxygen Consumption (VO2max)
The primary physiological variable investigated was the effect of the HIIT training while wearing the Elevation Training Mask had on VO2max (Table 4). The males significantly improved their VO2max values in all three conditions whereas the females improved but the results were not statistically significant. In a previous set of studies (Dreger and Paradis, 2011, Paradis and Dreger, 2011) it was noted that males responded to HIIT training with the SCBA produced significant results whereas the females results were selective. The improvement for the males was 11% in the SCBA VO2max testing condition, Dreger and Paradis (2011) found that HIIT training with the SCBA showed a 9.3% improvement in SCBA VO2max. Thus, indicating that physical training while wearing the ETM or SCBA produce similar results
| Table 4. Maximal oxygen consumption Values (VO2max [L•min-1]) pre and post test duringthe various testing conditions (mean ± standard deviation) | ||||||
| Condition | Males | Females | ||||
| Pre | Post | Pre | Post | |||
| RV | 3.36 ± 0.47 | 3.67 ± 0.48* | 2.40 ± 0.49 | |||
| SCBA | 2.62 ± 0.49 | 2.98 ± 0.79* | 1.99 ± 0.35 | |||
| ETM | 2.78 ± 0.35 | 2.99 ± 0.31* | 2.05 ± 0.30 | |||
*= significant difference from pretesting (p<0.05). RV = Rudolph valve condition. SCBA = self contained breathing apparatus condition. ETM = Elevation Training Mask condition.
Pulmonary Responses
Previous studies have shown that changes in pulmonary function are strongly associated with changes in VO2max. The maximum voluntary ventilation test during rest did not show any significant change pre to post training. However, the maximum values during exercise in the Rudolph valve condition was significantly increased in both the males and females, except for breathing frequency for males (Table 5). Similar patterns were found in the SCBA and ETM VO2max conditions, however significance was not reached. These results demonstrate the impact ETM has on the respiratory musculature.
| Table 5. Ventilatory responses pre and post test during the rudolph valve VO2max testing condition (mean ± standard deviation) | ||||||
| Variable | Males | Females | ||||
| Pre | Post | Pre | Post | |||
| VE (L•min-1) | 144 ± 32 | 158 ± 28* | ||||
| VT (L) | 2.57 ± 0.37 | 2.75 ± 0.39* | 2.21 ± 0.34 | |||
| F (breaths•min-1) | ||||||
*= significant difference from pretesting (p<0.05). VE = expired ventilation. VT = tidal volume. F = breathing frequency
Cardiac Responses
Maximal heart rate during the Rudolph valve VO2max condition was not significantly different pre to post testing (Table 6). The O2 pulse, which is a surrogate for stroke volume, showed a significant increase for males but not for females. However there was a 6.8% increase in O2 pulse for the females.
| Table 6. Cardiac responses pre and post test during the rudolph valve VO2max testingcondition (mean ± standard deviation) | ||||||
| Variable | Males | Females | ||||
| Pre | Post | Pre | Post | |||
| Heart Rate (beats•min-1) | 183 ± 10.6 | 180 ± 10.8 | 177 ± 8.36 | |||
| O2 pulse (ml•beat-1) | 18.1 ± 2.48 | 20.2 ± 2.38* | 13.7 ± 3.27 | |||
*= significant difference from pretesting (p<0.05).
Conclusions
The results of this study demonstrate that using the Elevation Training Mask while performing HIIT significantly improved cycling performance responses in males, specifically power output. The increased power output was related to the improvements in VO2max, which were attributed to improved pulmonary and cardiac function. Furthermore the combined ETM and HIIT were as effective as SCBA and HIIT.
The female responses to ETM and HIIT were similar to the results found by Paradis and Dreger (2011), in that, there were selective improvements that reached statistical significance. Thus, suggesting further investigation is required to determine the underlying reasons for the gender differences.
REFERENCES
Bilzon, J.L., Scarpello, E.G., Smith, C.V., Ravenhill, N.A., Rayson, M.P. (2001). Characterization of the metabolic demands of simulated shipboard Royal Navy fire- fighting tasks. Ergonomics. 44: 766-780.
Borg, G.A. (1982) Psychological bases of perceived exertion. Medicine and Science in Sport and Exercise. 14: 377-381.
Canadian Society for Exercise Physiology. (1998). The Canadian Physical Activity Fitness an Lifestyle Appraisal. Canadian Society for Exercise Physiology: Ottawa, ON.
Dreger, R.W., Jones, R.L., Petersen, S.R. (2006). Effects of the self-contained breathing apparatus and fire protective clothing on maximal oxygen uptake. Ergonomics. 49: 911- 920.
Dreger, R.W. and Petersen, S.R. (2008). Impact of fire-protective equipment on peak exercise in males and females. Applied Physiology, Nutrition and Metabolism. 33: S29.
Dreger, R.W. and Paradis, S.M. (2011). Effect of a high intensity interval training (HIIT) program while breathing from a self-contained breathing apparatus (SCBA) in males. Applied Physiology, Nutrition and Metabolism. 36: S313.
Eves, N.D., Petersen, S.R., Jones, R.L. (2002). Hyperoxia improves maximal exercise with the self-contained breathing apparatus (SCBA), Ergonomics. 45: 829-839.
Eves, N.D., Jones, R.L., Petersen, S.R. (2005). The influence of self-contained breathing apparatus (SCBA) on ventilatory function and incremental exercise. Canadian Journal of Applied Physiology. 30: 507-519.
Gledhill, N. and Jamnik, V.K. (1992a). Characterization of the physical demands of firefighting. Canadian Journal of Sports Science. 17: 207-213.
Gledhill, N. and Jamnik, V.K. (1992b). Development and validation of a fitness screening protocol for firefighter applicants. Canadian Journal of Sports Science. 17: 199-206.
Gormley S.E., Swain, D.P., High, R., Spina, R.J., Dowling, E.A., Kotipalli, U.S., Gandrakota, R. (2008). Effect of intensity of aerobic training on VO2max. Medicine Science Sports and Exercise. 40: 1336-1343.
Guidotti, T.L. and Clough, V.M. (1992). Occupational health concerns of firefighting. Annual Review of Public Health. 13: 151-171.
Helgerud, J., Høydal, K., Wang, E., Karlsen, T., Berg, P., Bjerkaas, M., Simonsen, T., Helgesen, C., Hjorth, N., Bach, R., Hoff, J. (2007). Aerobic high-intensity intervals improve VO2max more than moderate training. Medicine Science Sports and Exercise. 39: 665- 671.
Hoffman, J. (2006). Norms for Fitness, Performance, and Health. Human Kinetics. Champaign, IL.
Lusa, S., Louhevaara, V., Kinnunen, K. (1994). Are the job demands on physical work capacity equal for young and aging firefighters? J. Occupational Medicine. 36: 70-74.
Paradis, S.M. and Dreger, R.W. (2011). High intensity interval training (HIIT) while breathing from a self-contained breathing apparatus (SCBA) selectively improves VO2max values in females. Applied Physiology, Nutrition and Metabolism. 36: S343.
Petersen, S.R., Mayne, J.R., Hartley, T.C., Butcher, S.J., Jones, R.L. (2007). Regulator design improves peak exercise performance with self-contained breathing apparatus. Applied Physiology, Nutrition and Metabolism. 32: S71.
Ruppel, G.L. (2009). Manual of Pulmonary Function Testing (9th edition). Mosby: St. Louis, MI.
Sothmann, M.S., Saupe, K., Jasenof, D., Blaney, J. (1992). Heart rate response of firefighters to actual emergencies. Implications for cardiorespiratory fitness. Journal of Occupational Medicine. 34: 797-800.
Wisløff, U., Ellingsen, Ø., Kemi, O.J.(2009). High-intensity interval training to maximize cardiac benefits of exercise training. Exercise Sport Science Review. 37: 139-146.
APPENDIX A
Appendix B
Physical Activity Index (PAI)
Name:
Date: _-
Part 1 – When you engage in sport, fitness, activities, or active leisure, which description is most appropriate?
| Intensity descriptionsVery heavy: Continuous intense effort resulting in rapid heart rate | Points |
| of heavy breathing for the length of the activity | |
| Heavy: Bursts of effort that cause rapid heart rate or heavy breathing | |
| Moderate: Requires moderate effort and works up a sweat. | |
| Light: Requires light effort and is often intermittent. | |
| Minimal: Requires no extra effort. |
Part 2 – When you participate in the activity described in Part 1, how long do you exercise for?
| Duration description 35 min or more | Points 5 |
| 25-34 min | |
| 15-24 min | |
| 5-14 min | |
| Less than 5 min |
Part 3 – How often do you participate in the activity described in Part 1?
| Frequency description | Points |
| Daily | |
| 3-6 times per week | |
| 1-2 times per week | |
| 1-3 times per month | |
| Less than once per month |
PAI scoring:
Intensity points X Duration points X Frequency points Total
APPENDIX C
Applied Research Project Sign-Off Agreement
| Project Title: | Training Mask E7PROTO65 |
| Project Administrator: | novaNAIT |
| novaNAIT Project Officer: | Karen Eastland, Research/Project Officer |
| Lead Investigator / Co-Investigator: | Randy DregerScott Paradis |
| Project End Date: | March 7, 2013 |
PROJECT OVERVIEW :
The physical demands of firefighting have been well documented in the scientific literature. The protective equipment necessary for the firefighter to do their job has been shown to negatively impact work ability. The weight and heat stress associated with the equipment is a major factor. In addition, the self-contained breathing apparatus (SCBA) has been shown to be a significant limiter to performance.
Various strategies have been used to alleviate the impact of the SCBA including design modifications, enriched oxygen mixtures and physical training programs. The most cost effective method of counteracting the negative effect of the SCBA has been high intensity interval training while wearing the SCBA; in essence, a form of resistive breathing while exercising. However, the cost of an SCBA along with the cost of refilling the air cylinders could be cost prohibitive to small departments.
On the market are a number of resistive breathing devices that are typically used in a sitting position at rest, which is very different from the demands of firefighting. Recently, the development of a resistive breathing device that was designed to be used during exercise has become commercially available – the Elevation Training Mask (ETM). The ETM primarily provides an adjustable resistance during inspiration with a set resistance on expiration.
PROJECT OUTCOMES (brief statement outlining the overall outcome of the project)
This investigation set out to determine the effect the ETM had on indicators of performance. A training study of high intensity interval training (HIIT) was employed while wearing the ETM. Participants (8 males and 6 females) were pre and post tested on measures of pulmonary and cardiac function. The training consisted to cycle ergometry, 2 times per week for 5 weeks. Intensity was set at a load equivalent to a percentage of maximal oxygen consumption (VO2max) and was adjusted in a periodized model.
The response to the HIIT training while wearing the ETM showed an improvement in the primary variables of power output and VO2max in the Rudolph valve maximal test condition. The males showed significant improvements in VO2max (8.3%) and power output (9.8%) whereas; the females were 4.6% and 8.3% respectively (not significant). These findings were similar to previous investigation of HIIT training while wearing the SCBA (Dreger and Paradis, 2011; Paradis and Dreger, 2011).
The underlying physiological mechanisms for the improvements in VO2max and power output were related to increases in ventilator ability for both males and females (VE increased by approximately 9% in both groups [p<0.05]). In addition, cardiac function as described by O2 pulse, which is a surrogate for stroke volume, increased for both males and females 10% and 6.8%, respectively.
During the training sessions heart rate responses were measured at the end of each work and relief interval. The heart rate responses in the last work interval during the first and last training sessions were substantially lower for the males (180 vs. 176 beats•min-1) and females (180 vs. 173 beats•min-1). When averaged over the entire training session, there was a significant reduction in total heart rate responses from the first to last session. Further supporting the improved cardiopulmonary changes noted during the maximal testing.
The results of this study demonstrated that HIIT while wearing the Elevation Training Mask significantly improved selected variables for males and females. The males tended to have more variables significantly improve than females. These findings are similar to previous study using the same training protocols, but wearing the SCBA; thus, implying that the Elevation Training Mask is equally effective as the SCBA during HITT. It is suggested that further study of the female participants are required to determine the reasons why they do not respond to the training as their male counterparts.
MILESTONES ACHIEVED (as per Work plan)
Phase: Baseline set up of resistance technology and prototype of Training Mask
Tasks: This phase involved the fitting the mask with a custom made “cone” to collect expired air while the subjects are utilizing the mask. In addition, pressure sensors would be fitted to the mask to determine mask pressure throughout the trial. The fitted mask would then be examined to determine which resistance setting most closely matched the parameters off the SCBA, and calibrations set for the trial.
Outcomes/Outputs Achieved: Cones were designed and manufactured to fit the SCBA and Training Mask. Pressure testing was completed and found no difference in the SCBA pre and post cone attachment. The ETM was pressure tested, however, the generated pressures were great than the system tolerance and thus was unable to properly assess. It was determined that the minimal resistance be used on the ETM for the testing and training conditions.
Phase: Recruitment, Pre-test Evaluation, Training and Testing, and Post-test Evaluation
Tasks: This phase involved recruiting subjects to participate in the research study and then undergo a battery of pre-testing, supervised training program, and post-testing.
Outcomes/Outputs Achieved: Eight males and 6 females completed all of the pre testing, training and post testing.
Phase: Analysis and Reporting
Tasks: This phase involved the analysis of the data set and writing a Technical Consultancy Report (TCR).
Outcomes/Outputs Achieved: The data was analyzed for the subjects that completed the entire project and a TCR was produced.
