Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress.

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Version: Final published version
Serval ID
serval:BIB_DAEDD01578E6
Type
Article: article from journal or magazin.
Collection
Publications
Institution
Title
Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress.
Journal
PloS one
Author(s)
Girard O., Brocherie F., Morin J.B., Racinais S., Millet G.P., Périard J.D.
ISSN
1932-6203 (Electronic)
ISSN-L
1932-6203
Publication state
Published
Issued date
2017
Peer-reviewed
Oui
Volume
12
Number
2
Pages
e0170679
Language
english
Notes
Publication types: Journal Article
Publication Status: epublish
Abstract
Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions.
Eleven recreationally active males performed a 30-min warm-up followed by three sets of five 5-s sprints with 25-s recovery and 3-min between sets in each environment. Constant-velocity running for 1-min at 10 and 20 km.h-1 was also performed prior to and following sprinting.
Mean skin (37.2±0.7 vs. 32.7±0.8°C; P<0.001) and core (38.9±0.2 vs. 38.8±0.3°C; P<0.05) temperatures, together with thermal comfort (P<0.001) were higher following repeated sprinting in HOT vs. CON. Step frequency and vertical stiffness were lower (-2.6±1.6% and -5.5±5.5%; both P<0.001) and contact time (+3.2±2.4%; P<0.01) higher in HOT for the mean of sets 1-3 compared to CON. Running distance per sprint decreased from set 1 to 3 (-7.0±6.4%; P<0.001), with a tendency for shorter distance covered in HOT vs. CON (-2.7±3.4%; P = 0.06). Mean vertical (-2.6±5.5%; P<0.01), horizontal (-9.1±4.4%; P<0.001) and resultant ground reaction forces (-3.0±2.8%; P<0.01) along with vertical stiffness (-12.9±2.3%; P<0.001) and leg stiffness (-8.4±2.7%; P<0.01) decreased from set 1 to 3, independently of conditions. Propulsive power decreased from set 1 to 3 (-16.9±2.4%; P<0.001), with lower propulsive power values in set 2 (-6.6%; P<0.05) in HOT vs. CON. No changes in constant-velocity running patterns occurred between conditions, or from pre-to-post repeated-sprint exercise.
Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constant-velocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations.

Keywords
Adult, Body Temperature, Exercise Test, Fatigue, Hot Temperature, Humans, Male, Mechanical Phenomena, Neural Networks (Computer), Psychomotor Performance, Running, Stress, Physiological, Task Performance and Analysis
Pubmed
Web of science
Open Access
Yes
Create date
07/02/2017 17:54
Last modification date
20/08/2019 16:00
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