Twenty-Four Percent of Wildland Firefighters Reach Critical Levels of Serum Creatine Kinase During 80-Hour Critical Training

Katherine S. Christison; Joseph A. Sol; Shae C. Gurney; Charles L. Dumke

doi:10.1016/j.wem.2023.04.004

Twenty-Four Percent of Wildland Firefighters Reach Critical Levels of Serum Creatine Kinase During 80-Hour Critical Training

Katherine S. Christison
, Joseph A. Sol
, Shae C. Gurney
, Charles L. Dumke

School of Integrative Physiology and Athletic Training

University of Montana
United States Department of Agriculture

Research output: Contribution to journal › Article › peer-review

2 Scopus citations

Abstract

Introduction: Wildland firefighters (WLFFs) must undergo a 2-wk critical training (CT) period prior to deployment to the field. This stress may result in clinical risks, including severe muscle damage and rhabdomyolysis. We aimed to document the effects of WLFFs’ CT on physiologic markers of muscle damage and soreness. Methods: Two interagency hotshot crews (n=25) were followed during spring 2022 for 80 h of training. Activity counts as well as records of upper-body (US) and lower-body (LS) muscle soreness were collected daily. Body weight (BW) and skinfold measurements were recorded on Day 1 (D1) and D11 to estimate body fat (BF) and lean body weight (LBW). Blood was collected on D1 and D11 to measure muscle and liver damage markers. Results: Critical training resulted in significant elevations in creatine kinase (CK) (216.9±57.4 U/L vs 5166.4±1927.8 U/L, P=0.017) and lactate dehydrogenase (LDH) (175.5±4.0 IU/L vs 340.0±42.6 IU/L, P=0.001) despite no significant changes in BW, BF, LBW, cortisol, or testosterone. Main effects of time were seen in US and LS, peaking on D11 (US: 5.2±0.4 cm, P<0.001; LS: 5.5±0.4 cm, P<0.001). Those who spent the most minutes with activity counts of >1500 counts/min showed the greatest increase in CK and LDH. Conclusions: These data suggest that WLFFs undergo significant physiologic stressors, resulting in muscle soreness and damage during CT, with 6 of the 25 subjects reaching critical levels of serum CK. It appears that much of the muscle damage and soreness occurred because of unaccustomed WLFF job-specific tasks.

Original language	English
Pages (from-to)	334-340
Number of pages	7
Journal	Wilderness and Environmental Medicine
Volume	34
Issue number	3
DOIs	https://doi.org/10.1016/j.wem.2023.04.004
State	Published - Sep 2023

Funding

Financial/Material Support: This study was funded by the US Forest Service (16-CR-11138200-005). The authors report no potential conflicts of interest. Acknowledgments: The authors thank the participating fire crew members for their time and effort. Special gratitude is extended to Molly West and Skylar Brown for their data collection efforts. The results of this study are presented clearly and honestly and without fabrication, falsification, or inappropriate data manipulation. Author Contributions: study concept and design (KSC, JAS, SCG, CLD); obtaining funding (JAS, CLD); acquisition of the data (JAS, SCG); analysis of the data (KSC, CLD); drafting of the manuscript (KSC, CLD); critical revision of the manuscript (KSC, JAS, SCG, CLD); approval of the final manuscript (KSC, JAS, SCG, CLD). Financial/Material Support: This study was funded by the US Forest Service (16-CR-11138200-005). The authors report no potential conflicts of interest. Disclosures: The authors declare that they have no competing interests in access to these data or associations with companies involved with the products used in this research. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the US Department of Agriculture, Forest Service, the National Wildfire Coordination Group, or the Department of Interior.

Funders	Funder number
U.S. Department of the Interior
U.S. Forest Service-Retired	16-CR-11138200-005

UN SDGs

This output contributes to the following UN Sustainable Development Goals (SDGs)

SDG 3 Good Health and Well-being

Keywords

delayed-onset muscle soreness
occupational physiology
overreaching
rhabdomyolysis
wildland firefighting
Firefighters
Body Weight
Humans
L-Lactate Dehydrogenase/blood
Creatine Kinase/blood
Muscle, Skeletal
Myalgia/blood

Access to Document

10.1016/j.wem.2023.04.004

Cite this

@article{ed09b0ab25c64b08a8b566f0c3dc795e,

title = "Twenty-Four Percent of Wildland Firefighters Reach Critical Levels of Serum Creatine Kinase During 80-Hour Critical Training",

abstract = "Introduction: Wildland firefighters (WLFFs) must undergo a 2-wk critical training (CT) period prior to deployment to the field. This stress may result in clinical risks, including severe muscle damage and rhabdomyolysis. We aimed to document the effects of WLFFs{\textquoteright} CT on physiologic markers of muscle damage and soreness. Methods: Two interagency hotshot crews (n=25) were followed during spring 2022 for 80 h of training. Activity counts as well as records of upper-body (US) and lower-body (LS) muscle soreness were collected daily. Body weight (BW) and skinfold measurements were recorded on Day 1 (D1) and D11 to estimate body fat (BF) and lean body weight (LBW). Blood was collected on D1 and D11 to measure muscle and liver damage markers. Results: Critical training resulted in significant elevations in creatine kinase (CK) (216.9±57.4 U/L vs 5166.4±1927.8 U/L, P=0.017) and lactate dehydrogenase (LDH) (175.5±4.0 IU/L vs 340.0±42.6 IU/L, P=0.001) despite no significant changes in BW, BF, LBW, cortisol, or testosterone. Main effects of time were seen in US and LS, peaking on D11 (US: 5.2±0.4 cm, P<0.001; LS: 5.5±0.4 cm, P<0.001). Those who spent the most minutes with activity counts of >1500 counts/min showed the greatest increase in CK and LDH. Conclusions: These data suggest that WLFFs undergo significant physiologic stressors, resulting in muscle soreness and damage during CT, with 6 of the 25 subjects reaching critical levels of serum CK. It appears that much of the muscle damage and soreness occurred because of unaccustomed WLFF job-specific tasks.",

keywords = "delayed-onset muscle soreness, occupational physiology, overreaching, rhabdomyolysis, wildland firefighting, Firefighters, Body Weight, Humans, L-Lactate Dehydrogenase/blood, Creatine Kinase/blood, Muscle, Skeletal, Myalgia/blood",

author = "Christison, \{Katherine S.\} and Sol, \{Joseph A.\} and Gurney, \{Shae C.\} and Dumke, \{Charles L.\}",

note = "Funding Information: Financial/Material Support: This study was funded by the US Forest Service (16-CR-11138200-005). The authors report no potential conflicts of interest. Funding Information: Acknowledgments: The authors thank the participating fire crew members for their time and effort. Special gratitude is extended to Molly West and Skylar Brown for their data collection efforts. The results of this study are presented clearly and honestly and without fabrication, falsification, or inappropriate data manipulation. Author Contributions: study concept and design (KSC, JAS, SCG, CLD); obtaining funding (JAS, CLD); acquisition of the data (JAS, SCG); analysis of the data (KSC, CLD); drafting of the manuscript (KSC, CLD); critical revision of the manuscript (KSC, JAS, SCG, CLD); approval of the final manuscript (KSC, JAS, SCG, CLD). Financial/Material Support: This study was funded by the US Forest Service (16-CR-11138200-005). The authors report no potential conflicts of interest. Disclosures: The authors declare that they have no competing interests in access to these data or associations with companies involved with the products used in this research. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the US Department of Agriculture, Forest Service, the National Wildfire Coordination Group, or the Department of Interior. Publisher Copyright: {\textcopyright} 2023 Wilderness Medical Society Copyright {\textcopyright} 2023 Wilderness Medical Society. All rights reserved.",

year = "2023",

month = sep,

doi = "10.1016/j.wem.2023.04.004",

language = "English",

volume = "34",

pages = "334--340",

journal = "Wilderness and Environmental Medicine",

issn = "1080-6032",

publisher = "SAGE Publications Inc.",

number = "3",

}

TY - JOUR

T1 - Twenty-Four Percent of Wildland Firefighters Reach Critical Levels of Serum Creatine Kinase During 80-Hour Critical Training

AU - Christison, Katherine S.

AU - Sol, Joseph A.

AU - Gurney, Shae C.

AU - Dumke, Charles L.

N1 - Funding Information: Financial/Material Support: This study was funded by the US Forest Service (16-CR-11138200-005). The authors report no potential conflicts of interest. Funding Information: Acknowledgments: The authors thank the participating fire crew members for their time and effort. Special gratitude is extended to Molly West and Skylar Brown for their data collection efforts. The results of this study are presented clearly and honestly and without fabrication, falsification, or inappropriate data manipulation. Author Contributions: study concept and design (KSC, JAS, SCG, CLD); obtaining funding (JAS, CLD); acquisition of the data (JAS, SCG); analysis of the data (KSC, CLD); drafting of the manuscript (KSC, CLD); critical revision of the manuscript (KSC, JAS, SCG, CLD); approval of the final manuscript (KSC, JAS, SCG, CLD). Financial/Material Support: This study was funded by the US Forest Service (16-CR-11138200-005). The authors report no potential conflicts of interest. Disclosures: The authors declare that they have no competing interests in access to these data or associations with companies involved with the products used in this research. The views and conclusions contained herein are those of the authors and should not be interpreted as necessarily representing the official policies or endorsements, either expressed or implied, of the US Department of Agriculture, Forest Service, the National Wildfire Coordination Group, or the Department of Interior. Publisher Copyright: © 2023 Wilderness Medical Society Copyright © 2023 Wilderness Medical Society. All rights reserved.

PY - 2023/9

Y1 - 2023/9

N2 - Introduction: Wildland firefighters (WLFFs) must undergo a 2-wk critical training (CT) period prior to deployment to the field. This stress may result in clinical risks, including severe muscle damage and rhabdomyolysis. We aimed to document the effects of WLFFs’ CT on physiologic markers of muscle damage and soreness. Methods: Two interagency hotshot crews (n=25) were followed during spring 2022 for 80 h of training. Activity counts as well as records of upper-body (US) and lower-body (LS) muscle soreness were collected daily. Body weight (BW) and skinfold measurements were recorded on Day 1 (D1) and D11 to estimate body fat (BF) and lean body weight (LBW). Blood was collected on D1 and D11 to measure muscle and liver damage markers. Results: Critical training resulted in significant elevations in creatine kinase (CK) (216.9±57.4 U/L vs 5166.4±1927.8 U/L, P=0.017) and lactate dehydrogenase (LDH) (175.5±4.0 IU/L vs 340.0±42.6 IU/L, P=0.001) despite no significant changes in BW, BF, LBW, cortisol, or testosterone. Main effects of time were seen in US and LS, peaking on D11 (US: 5.2±0.4 cm, P<0.001; LS: 5.5±0.4 cm, P<0.001). Those who spent the most minutes with activity counts of >1500 counts/min showed the greatest increase in CK and LDH. Conclusions: These data suggest that WLFFs undergo significant physiologic stressors, resulting in muscle soreness and damage during CT, with 6 of the 25 subjects reaching critical levels of serum CK. It appears that much of the muscle damage and soreness occurred because of unaccustomed WLFF job-specific tasks.

AB - Introduction: Wildland firefighters (WLFFs) must undergo a 2-wk critical training (CT) period prior to deployment to the field. This stress may result in clinical risks, including severe muscle damage and rhabdomyolysis. We aimed to document the effects of WLFFs’ CT on physiologic markers of muscle damage and soreness. Methods: Two interagency hotshot crews (n=25) were followed during spring 2022 for 80 h of training. Activity counts as well as records of upper-body (US) and lower-body (LS) muscle soreness were collected daily. Body weight (BW) and skinfold measurements were recorded on Day 1 (D1) and D11 to estimate body fat (BF) and lean body weight (LBW). Blood was collected on D1 and D11 to measure muscle and liver damage markers. Results: Critical training resulted in significant elevations in creatine kinase (CK) (216.9±57.4 U/L vs 5166.4±1927.8 U/L, P=0.017) and lactate dehydrogenase (LDH) (175.5±4.0 IU/L vs 340.0±42.6 IU/L, P=0.001) despite no significant changes in BW, BF, LBW, cortisol, or testosterone. Main effects of time were seen in US and LS, peaking on D11 (US: 5.2±0.4 cm, P<0.001; LS: 5.5±0.4 cm, P<0.001). Those who spent the most minutes with activity counts of >1500 counts/min showed the greatest increase in CK and LDH. Conclusions: These data suggest that WLFFs undergo significant physiologic stressors, resulting in muscle soreness and damage during CT, with 6 of the 25 subjects reaching critical levels of serum CK. It appears that much of the muscle damage and soreness occurred because of unaccustomed WLFF job-specific tasks.

KW - delayed-onset muscle soreness

KW - occupational physiology

KW - overreaching

KW - rhabdomyolysis

KW - wildland firefighting

KW - Firefighters

KW - Body Weight

KW - Humans

KW - L-Lactate Dehydrogenase/blood

KW - Creatine Kinase/blood

KW - Muscle, Skeletal

KW - Myalgia/blood

UR - https://www.scopus.com/pages/publications/85160443360

U2 - 10.1016/j.wem.2023.04.004

DO - 10.1016/j.wem.2023.04.004

M3 - Article

C2 - 37258394

AN - SCOPUS:85160443360

SN - 1080-6032

VL - 34

SP - 334

EP - 340

JO - Wilderness and Environmental Medicine

JF - Wilderness and Environmental Medicine

IS - 3

ER -

Twenty-Four Percent of Wildland Firefighters Reach Critical Levels of Serum Creatine Kinase During 80-Hour Critical Training

Abstract

Funding

UN SDGs

Keywords

Access to Document

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