Further characterization and validation of the oxygen uptake efficiency slope for persons with multiple sclerosis.

OBJECTIVE: To further characterize the oxygen uptake efficiency slope (OUES) in persons with multiple sclerosis through a direct comparison with matched controls, and by examining differences across the multiple sclerosis disability spectrum. Also, to validate the OUES as an alternative method, which can be derived from submaximal exercise testing, for expressing cardiorespiratory fitness in persons with mild-to-severe multiple sclerosis. PARTICIPANTS: A total of 62 participants (Expanded Disability Status Scale (EDSS) = 1.5-6.5) with MS and 21 non-multiple sclerosis controls completed a symptom-limited cardiopulmonary exercise test. RESULTS: The OUES was significantly lower in persons with multiple sclerosis (mean 1,708.5 (standard deviation (SD) 503.7)) compared with non-multiple sclerosis controls (mean 2074.2 (SD 823.2)). With regards to the multiple sclerosis sample, there was a significant difference in the OUES (F[2,59] = 8.9, p < 0.001, ηρ2 = 0.23) across the multiple sclerosis disability spectrum. The OUES was significantly correlated with both OUES50 (r = 0.86) and OUES75 (r = 0.91), and Bland-Altman plots demonstrated agreement between OUES and submaximal OUES values. CONCLUSION: Overall, the OUES is a viable method for expressing cardiorespiratory fitness in individuals with multiple sclerosis, and submaximal OUES is an appropriate alternative when maximal exercise testing is not feasible.

Objectively measured sedentary behavior and brain volumetric measurements in multiple sclerosis.

AIM: This study examined the association between sedentary behavior patterns and whole brain gray matter (GM), white matter (WM) and subcortical GM structures in persons with multiple sclerosis (MS). METHODS: 36 persons with MS wore an accelerometer and underwent a brain MRI. Whole brain GM and WM and deep GM structures were calculated from 3D T1-weighted structural brain images. RESULTS: There were statistically significant (p < 0.01) and moderate or large associations between number of sedentary bouts/day and brain volume measures. The primary result was a consistent negative association between number of sedentary bouts/day and whole brain GM and WM, and deep GM structures. CONCLUSION: We provide novel evidence for decreased brain volume as a correlate of a sedentary behavior pattern in persons with MS.

Firefighter exercise protocols conducted in an environmental chamber: developing a laboratory-based simulated firefighting protocol.

A standard exercise protocol that allows comparisons across various ergonomic studies would be of great value for researchers investigating the physical and physiological strains of firefighting and possible interventions for reducing the demands. We compared the pattern of cardiorespiratory changes from 21 firefighters during simulated firefighting activities using a newly developed firefighting activity station (FAS) and treadmill walking both performed within an identical laboratory setting. Data on cardiorespiratory parameters and core temperature were collected continuously using a portable metabolic unit and a wireless ingestible temperature probe. Repeated measures ANOVA indicated distinct patterns of change in cardiorespiratory parameters and heart rate between conditions. The pattern consisted of alternating periods of peaks and nadirs in the FAS that were qualitatively and quantitatively similar to live fire activities, whereas the same parameters increased logarithmically in the treadmill condition. Core temperature increased in a similarly for both conditions, although more rapidly in the FAS. Practitioner Summary: The firefighting activity station (FAS) yields a pattern of cardiorespiratory responses qualitatively and quantitatively similar to live fire activities, significantly different than treadmill walking. The FAS can be performed in a laboratory/clinic, providing a potentially standardised protocol for testing interventions to improve health and safety and conducting return to duty decisions.

Patterns and Predictors of Change in Moderate-to-Vigorous Physical Activity Over Time in Multiple Sclerosis.

BACKGROUND: Physical inactivity is common in persons with multiple sclerosis (MS), but there is very little known about the pattern and predictors of changes in physical activity over time. PURPOSE: This study examined changes in moderate-to-vigorous physical activity (MVPA) over a 30-month time period and the demographic and clinical predictors of such changes in relapsing-remitting MS (RRMS). METHODS: 269 persons with MS wore an accelerometer for a 7-day period and completed a demographic/clinical scale every 6 months over a 30-month period. Data were analyzed using latent class growth modeling (LCGM). RESULTS: LCGM identified a two-class model for changes in levels of MVPA over time. Class 1 involved higher initial levels of MVPA and linear decreases in MVPA over time, whereas Class 2 involved lower initial levels of MVPA and linear increases in MVPA over time. LCGM further indicated that males were more likely (OR = 5.8, P < .05) and those with higher disability status were less likely (OR = 0.51, P < .05) to belong to Class 1 than Class 2. CONCLUSION: Levels of MVPA change over time in persons with RRMS and the pattern of change suggests that behavioral physical activity interventions for persons with MS might target men and those with lower disability.

Physical activity, sedentary behavior, and aerobic capacity in persons with multiple sclerosis.

BACKGROUND: There is substantial evidence that exercise training improves aerobic capacity among people with multiple sclerosis (MS), but less is known about the associations between physical activity and sedentary behaviors with aerobic capacity. OBJECTIVE: This study examined if objectively-measured moderate-to-vigorous (MVPA) and light (LPA) physical activity and sedentary behavior were associated with peak aerobic capacity (VO2peak) measured using an established protocol for conducting a maximal, incremental exercise test in persons with MS. METHODS: The study involved a cross-sectional, observational study design and included 49 persons with MS. Participants wore an accelerometer around the waist during the waking hours for a 7-day period as a measure of physical activity and sedentary behaviors, and completed a maximal, incremental exercise test on an electronically-braked, computer-controlled cycle ergometer with open-circuit spirometry for measuring VO2peak. RESULTS: VO2peak was significantly correlated with MVPA (r=0.53, p<0.001) and LPA (r=0.39, p<0.01), but not sedentary behavior (r=-0.12, p=0.44). Linear regression analysis indicated that MVPA (B=0.19, SE B=0.04, ß=0.51, p<0.001) and LPA (B=0.02, SE B=0.01, ß=0.30, p<0.05), but not sedentary behavior (B=-0.01, SE B=0.01, ß=-0.14, p=0.26), explained significant variance in VO2peak (R2=0.40). CONCLUSION: We provide the first evidence that MVPA and LPA represent concurrent correlates of VO2peak and both could be targeted for improving aerobic capacity in persons with MS.

Systematically developed pilot randomized controlled trial of exercise and cognition in persons with multiple sclerosis.

Cognitive impairment is common and debilitating among persons with multiple sclerosis (MS) and might be managed with exercise training. The present pilot study adopted a single-blind randomized controlled trial (RCT) design and is the first to examine the effect of a systematically developed, progressive treadmill walking exercise training intervention on cognition among fully ambulatory persons with MS. Ten fully ambulatory females with MS were randomly assigned into exercise training intervention or waitlist control conditions. The intervention condition involved 12 weeks of supervised, progressive chronic treadmill walking exercise training. Participants underwent measures of cognition (i.e., cognitive processing speed (CPS), executive function), walking performance, and cardiorespiratory fitness before and after the 12-week period; baseline and follow-up assessments were performed by blinded assessors. Overall, there were large intervention effects on CPS (d = 0.95), walking performance (d = 0.76), and cardiorespiratory fitness (d > 1.08). The change in cardiorespiratory fitness was significantly associated with change in CPS (r = .60), but not walking performance. This small pilot RCT provides preliminary proof-of-concept data supporting progressive treadmill walking exercise training for potentially improving CPS, walking performance, and cardiorespiratory fitness in fully ambulatory persons with MS, and that improved fitness might be a possible mechanism for improved CPS.

Effects of exercise in a relapsing-remitting model of experimental autoimmune encephalomyelitis.

Previous research has examined the effects of exercise in experimental autoimmune encephalomyelitis (EAE), the animal model of multiple sclerosis. However, all previous studies have utilized a chronic model of EAE, with exercise delivered prior to or immediately after induction of EAE. To our knowledge, no study has examined the effects of exercise delivered during a remission period after initial disease onset in a relapsing-remitting model of EAE (RR-EAE). The current study examines the effects of both voluntary wheel running and forced treadmill exercise on clinical disability and hippocampal brain-derived neurotrophic factor (BDNF) in SJL mice with RR-EAE. The results demonstrate no significant effects of exercise delivered during remission after initial disease onset on clinical disability scores or levels of hippocampal BDNF in mice with RR-EAE. Furthermore, our results demonstrate no significant increase in citrate synthase activity in the gastrocnemius and soleus muscles of mice in the running wheel or treadmill conditions compared with the sedentary condition. These results suggest that the exercise stimuli might have been insufficient to elicit differences in clinical disability or hippocampal BDNF among treatment conditions. © 2016 Wiley Periodicals, Inc.

Levels and Rates of Physical Activity in Older Adults with Multiple Sclerosis.

There is much evidence supporting the safety and benefits of physical activity in adults with multiple sclerosis (MS) and recent evidence of beneficial effects on physical function in older adults with MS. However, there is very little known about physical activity participation in older adults with conditions such as MS. This study compared levels of physical activity (i.e., sedentary behavior, light physical activity (LPA), and moderate-to-vigorous physical activity (MVPA)) and rates of meeting public health guidelines for MVPA (i.e., ≥30 min/day) among young (i.e., ages 20-39 years), middle-aged (i.e., ages 40-59 years) and older adults (i.e., ages ≥60 years) with MS. The sample included 963 persons with MS who provided demographic and clinical information and wore an accelerometer for a 7-day period. The primary analysis involved a between-subjects ANOVA on accelerometer variables (i.e., accelerometer wear time; number of valid days; sedentary behavior in min/day; LPA in min/day; and MVPA in min/day). Collectively, our data indicated that older adults with MS engaged in less MVPA and more sedentary behavior than middle-aged and young adults with MS. Such results highlight the importance of developing physical activity interventions as an effective means for managing the progression and consequences of MS in older adults.

Reliability of Accelerometer Scores for Measuring Sedentary and Physical Activity Behaviors in Persons With Multiple Sclerosis.

This brief research note examined the reliability of scores from an accelerometer as measures of sedentary and physical activity behaviors in persons with multiple sclerosis (MS). The analysis was performed on a combined data set from 2 previous longitudinal investigations of physical activity in MS. We focused on the number of days required to reliably estimate sedentary behavior, based on time spent in sedentary behavior per day and number of sedentary breaks, number of long sedentary bouts, and average length of sedentary bouts per day. We further examined the number of days required to reliably estimate physical activity behavior, based on time spent in light and moderate-to-vigorous physical activity and average length of activity bouts per day. Between 4-6 days of monitoring and 3-7 days of monitoring were necessary for good reliability of scores from all sedentary outcomes and physical activity outcomes, respectively. These results should guide research and practice examining sedentary and physical activity behaviors using accelerometry in persons with MS.

Comprehensive Profile of Cardiopulmonary Exercise Testing in Ambulatory Persons with Multiple Sclerosis.

BACKGROUND: The study and application of exercise in multiple sclerosis (MS) often requires cardiopulmonary exercise testing (CPET) to provide a comprehensive assessment of exercise tolerance and responses, including an evaluation of the pulmonary, cardiovascular, and skeletal muscle systems. Research on CPET in persons with MS has considerable limitations, including small sample sizes, often without controls; not reporting outcomes across disability status; and different modalities of exercise testing across studies. Although some key outcome variables of CPET have been studied in persons with MS, additional calculated variables have not been directly studied. OBJECTIVE: The objective of this study was to provide a comprehensive examination of outcome variables from CPET among persons with MS and healthy controls. METHODS: We included data from 162 persons with MS and 80 healthy controls who underwent CPET on a leg ergometer and satisfied criteria for valid testing for measuring oxygen uptake (VO2), carbon dioxide production (VCO2), ventilation (VE), respiratory exchange ratio, work rate, and heart rate (HR). Calculated variables [i.e. ventilatory anaerobic threshold (VO2/VCO2), VE/VCO2 slope, VO2/power slope, VO2/HR slope, and oxygen uptake efficiency slope] were processed using standard guidelines. We examined differences in the CPET variables between groups (e.g. MS vs. controls and categories of mild, moderate, and severe disability status) using analysis of covariance (ANCOVA), controlling for age, sex, body mass index, and disease duration. RESULTS: Overall, persons with MS demonstrate alterations in outcomes from CPET compared with controls, and these are generally exacerbated with increasing disability. CONCLUSION: Our results provide novel information for the evaluation of CPET in MS for developing exercise prescriptions and documenting adaptations with exercise training based on the comprehensive variables obtained during CPET.

Physical Fitness Assessment Across the Disability Spectrum in Persons With Multiple Sclerosis: A Comparison of Testing Modalities.

BACKGROUND AND PURPOSE: Appropriate assessment of physical fitness (ie, aerobic capacity and muscular strength) is necessary for the design and evaluation of exercise training in multiple sclerosis (MS). However, this is challenging in persons with substantial disability, because of physical inaccessibility and insensitivity of certain exercise testing modalities. This study compared different methods of measuring cardiorespiratory (arm ergometer vs recumbent stepper) and muscular (hand-held dynamometry vs computerized dynamometry) fitness across the MS disability spectrum. Associations between physical fitness and other measures that represented all domains of the International Classification of Functioning, Disability and Health (ICF) were also examined. METHODS: Sixty-four participants with MS completed 2 symptom-limited cardiorespiratory fitness and muscular strength tests. We also assessed disability, cognition, fatigue, walking speed and endurance, health-related quality of life, and activities of daily living. RESULTS: Across all levels of disability, peak aerobic capacity assessed by recumbent stepping was higher compared with arm ergometry (P < 0.001). Peak torque of the knee extensors and knee flexors was significantly higher assessed by computerized dynamometry compared with hand-held dynamometry (P < 0.001). Aerobic capacity and peak torque decreased as a function of increasing disability (P < 0.001). Significant, moderate to strong correlations were observed between the physical fitness measures and measures representing all domains of the ICF, irrespective of the fitness testing mode. DISCUSSION AND CONCLUSIONS: Overall, peak physical capacity was higher when assessed by recumbent stepping and computerized dynamometry. The assessment and prescription of exercise in MS should be based on these modalities to provide the most appropriate stimulus for exercise training adaptations. There continues to be an important association between physical fitness and other measures that represent all domains of the ICF, regardless of fitness assessment mode.Video Abstract available for additional insights from the authors (see Video Abstract, Supplemental Digital Content 1, http://links.lww.com/JNPT/A109).

Objectively Measured Physical Activity Is Associated with Brain Volumetric Measurements in Multiple Sclerosis.

BACKGROUND: Little is known about physical activity and its association with volumes of whole brain gray matter and white matter and deep gray matter structures in persons with multiple sclerosis (MS). PURPOSE: This study examined the association between levels of physical activity and brain volumetric measures from magnetic resonance imaging (MRI) in MS. METHOD: 39 persons with MS wore an accelerometer for a 7-day period and underwent a brain MRI. Normalized GM volume (NGMV), normalized WM volume (NWMV), and deep GM structures were calculated from 3D T1-weighted structural brain images. We conducted partial correlations (pr) controlling for demographic and clinical variables. RESULTS: Moderate-to-vigorous physical activity (MVPA) was significantly associated with NGMV (pr = 0.370, p < 0.05), NWMV (pr = 0.433, p < 0.01), hippocampus (pr = 0.499, p < 0.01), thalamus (pr = 0.380, p < 0.05), caudate (pr = 0.539, p < 0.01), putamen (pr = 0.369, p < 0.05), and pallidum (pr = 0.498, p < 0.01) volumes, when controlling for sex, age, clinical course of MS, and Expanded Disability Status Scale score. There were no associations between sedentary and light physical activity with MRI outcomes. CONCLUSION: Our results provide the first evidence that MVPA is associated with volumes of whole brain GM and WM and deep GM structures that are involved in motor and cognitive functions in MS.

Does the effect of a physical activity behavioral intervention vary by characteristics of people with multiple sclerosis?

BACKGROUND: Behavioral interventions have significantly increased physical activity in people with multiple sclerosis (MS). Nevertheless, there has been interindividual variability in the pattern and magnitude of change. This study documented the efficacy and variability of a behavioral intervention for changing physical activity and examined the possibility that efficacy varied by the characteristics of individuals with MS. METHODS: Eighty-two people with MS were randomly assigned to one of two conditions: behavioral intervention (n = 41) or waitlist control (n = 41). We collected information before the study on MS type, disability status, weight status based on body-mass index, and current medications. Furthermore, all participants completed the Godin Leisure Time Exercise Questionnaire and the abbreviated International Physical Activity Questionnaire and wore an accelerometer for 1 week to measure minutes of moderate-to-vigorous physical activity before and after the 6-month intervention period. RESULTS: Analysis of covariance (ANCOVA) indicated that participants in the behavioral intervention had significantly higher levels of physical activity than control participants after the 6-month period (P < .001). There was substantial interindividual variability in the magnitude of change, and ANCOVA indicated that MS type (relapsing vs. progressive) (P < .01), disability status (mild vs. moderate) (P < .01), and weight status (normal weight vs. overweight/obese) (P < .05) moderated the efficacy of the behavioral intervention. CONCLUSIONS: The behavioral intervention was associated with improvements in physical activity, particularly for those with mild disability, relapsing-remitting MS, or normal weight status.

Impairment and disability in persons with MS: do functional performance or functional limitations matter?

Persons with multiple sclerosis (MS) often demonstrate impairment in cardiorespiratory and musculoskeletal systems that may be associated with functional performance, functional limitations, and disability limitations. This study examined such relationships in persons with MS using Nagi's disablement model and its subsequent conceptual modifications. The sample included 63 persons with MS (75% relapsing-remitting MS, median EDSS = 4.0, and mean MS duration = 13.1 years) who underwent measurements of aerobic fitness and muscular strength (i.e. impairment), functional performance, functional limitations, and disability limitations. The data were primarily examined using path analysis in Mplus 7.0. Our final model provided an excellent fit for the data (χ² = 0.67, df = 3, p = 0.88, SRMR = 0.01, and CFI = 1.00). The final model indicated that aerobic fitness and muscular strength were indirectly associated with disability limitations in persons with MS through a pathway that included functional limitations (indirect path coefficients of 0.29 and 0.20, respectively), but not functional performance. Aerobic fitness and muscular strength may be the important targets of exercise training interventions for improving perceived functional limitations and disability limitations in persons with MS.

Relationships among physical inactivity, deconditioning, and walking impairment in persons with multiple sclerosis.

BACKGROUND AND PURPOSE: We have previously proposed a conceptual model of physical inactivity, physiological deconditioning, and walking impairment in persons with multiple sclerosis (MS) that suggests engaging in physical activity and improving physiological conditioning may lead to improvements in walking performance. This cross-sectional study examined the nature of associations among physical activity, aerobic capacity, and walking performance in persons with MS and healthy controls. METHODS: The sample included 31 persons with MS and 31 controls matched by age, sex, height, and weight. Participants completed the 6-minute walk (6MW), wore an ActiGraph model GT3X accelerometer for 7 days as an objective measure of physical activity (expressed as time spent in moderate-to-vigorous physical activity [MVPA]), and completed an incremental exercise test on a cycle ergometer as a measure of aerobic capacity (VO2peak). RESULTS: Hierarchical linear regression analyses indicated that MVPA and VO2peak partially explained group differences in 6MW performance (R = 0.782), although group remained a significant predictor of 6MW performance (ß = 0.304; P < 0.001). Path analysis indicated that group had both statistically significant direct and indirect effects on 6MW performance, and the indirect effect operated through pathways involving MVPA and VO2peak. DISCUSSION AND CONCLUSIONS: These results provide direct preliminary evidence that physiological deconditioning, perhaps occurring as a result of physical inactivity, may explain variability in walking impairment in persons with MS. These findings support the design and implementation of targeted interventions for improving walking impairment in this population. VIDEO ABSTRACT AVAILABLE: for more insights from the authors (see Supplemental Digital Content 1, http://links.lww.com/JNPT/A93).

Reliability of gait in multiple sclerosis over 6 months.

Gait impairment is ubiquitous in multiple sclerosis (MS) and is often characterized by alterations in spatiotemporal parameters of gait. There is limited information concerning reliability of spatiotemporal gait parameters over clinical timescales (e.g. 6 months). The current report provides novel evidence that gait parameters of 74 ambulatory persons with MS with mild-to-moderate disability are reliable over 6-months (ICC's for overall sample range from 0.56 to 0.91) in the absence of any intervention above and beyond standard care. Such data can inform clinical decision-making and power analyses for designing RCTs (i.e., sample size estimates) involving persons with MS.

Experimental protocol of a randomized controlled clinical trial investigating exercise, subclinical atherosclerosis, and walking mobility in persons with multiple sclerosis.

BACKGROUND: This randomized controlled trial (RCT) will investigate the effects of a home-based aerobic exercise training regimen (i.e., cycle ergometry) on subclinical atherosclerosis and walking mobility in persons with multiple sclerosis (MS) and minimal disability. METHODS/DESIGN: This RCT will recruit 54 men and women who have an Expanded Disability Status Scale characteristic of the 1st stage of MS (i.e., 0-4.0) to participate in a 3 month exercise or stretching intervention, with assessments of subclinical atherosclerosis and walking mobility conducted at baseline, week 6 (midpoint), and week 12 (conclusion) of the program. The exercise intervention will consist of 3 days/week of cycling, with a gradual increase of duration followed by an increase in intensity across the 3 month period. The attention-control condition will incorporate stretching activities and will require the same contact time commitment as the exercise condition. Both study groups will participate in weekly video chat sessions with study personnel in order to monitor and track program adherence. Primary outcomes will consist of assessments of vascular structure and function, as well as several walking tasks. Additional outcomes will include questionnaires, cardiorespiratory fitness assessment, and a 1-week free-living physical activity assessment. DISCUSSION: This investigation will increase understanding of the role of aerobic exercise as part of a treatment plan for managing subclinical atherosclerosis and improving walking mobility persons in the 1st stage of MS. Overall, this study design has the potential to lead to effective aerobic exercise intervention strategies for this population and improve program adherence.

Physiological responses to simulated firefighter exercise protocols in varying environments.

For decades, research to quantify the effects of firefighting activities and personal protective equipment on physiology and biomechanics has been conducted in a variety of testing environments. It is unknown if these different environments provide similar information and comparable responses. A novel Firefighting Activities Station, which simulates four common fireground tasks, is presented for use with an environmental chamber in a controlled laboratory setting. Nineteen firefighters completed three different exercise protocols following common research practices. Simulated firefighting activities conducted in an environmental chamber or live-fire structures elicited similar physiological responses (max heart rate: 190.1 vs 188.0 bpm, core temperature response: 0.047°C/min vs 0.043°C/min) and accelerometry counts. However, the response to a treadmill protocol commonly used in laboratory settings resulted in significantly lower heart rate (178.4 vs 188.0 bpm), core temperature response (0.037°C/min vs 0.043°C/min) and physical activity counts compared with firefighting activities in the burn building. Practitioner Summary: We introduce a new approach for simulating realistic firefighting activities in a controlled laboratory environment for ergonomics assessment of fire service equipment and personnel. Physiological responses to this proposed protocol more closely replicate those from live-fire activities than a traditional treadmill protocol and are simple to replicate and standardise.

Mobility disability and the pattern of accelerometer-derived sedentary and physical activity behaviors in people with multiple sclerosis.

OBJECTIVE: Low physical activity and high sedentary behavior levels are major concerns in persons with multiple sclerosis (MS) and these differ depending on the level of mobility disability. However, the manner in which daily activity is accumulated is currently unknown in this population. METHODS: A secondary analysis was performed on a combined data set of persons with MS from two previous investigations of physical activity and symptomatic or quality of life outcomes in the United States over a two year period (2007-2009). Mobility disability status was determined using the Patient Determined Disease Steps (PDDS) while activity behavior was objectively monitored using an ActiGraph accelerometer for 7 days. RESULTS: Persons with MS who have mobility disability were involved in sedentary behavior, light and moderate intensity activity for 65%, 34% and 1% of the day, respectively compared to 60%, 37%, and 3%, respectively in those without mobility disability (p < 0.05). Breaks in sedentary time did not differ by mobility disability status. Compared to those without mobility disability, the average number of sedentary bouts longer than 30 min was greater in those with mobility disability (p = 0.016). CONCLUSION: Persons with MS with mobility disability are less active, engage in more sedentary behavior and accumulate prolonged sedentary bouts.

A modified SCBA facepiece for accurate metabolic data collection from firefighters.

To better assess the energy expenditure and exertion of firefighters during simulated firefighting activities, a commercial firefighter self-contained breathing apparatus (SCBA) facepiece was modified to interface with a portable metabolic monitoring device (Cosmed K4b(2)) while still functioning as a positive pressure SCBA air supply. To validate the device, standard National Fire Protection Association 1981 SCBA function tests were conducted and 14 subjects performed variable-workload assessments using all combinations of two test devices (Cosmed K4b(2) and metabolic cart) and two masks (modified SCBA facepiece and stock manufacturer-supplied breath collection). Metabolic data collected with the Cosmed K4b(2) via the modified facepiece were found to be accurate when compared to a ParvoMedics Truemax 2400 metabolic cart (average per cent difference: 4.6%). This modified facepiece design is suitable for use in metabolic studies requiring the utilisation of an SCBA system. Furthermore, the well-established overestimation of oxygen consumption from the Cosmed K4b(2) system was replicated.