Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress

Olivier Girard, Franck Brocherie, Jean-Benoit Morin, Sébastien Racinais, Grégoire P. Millet, Julien D Périard

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Purpose Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions. Methods 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. Constantvelocity running for 1-min at 10 and 20 km.h -1 was also performed prior to and following sprinting. Results: 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. Conclusions: Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constantvelocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations.

Original languageEnglish
Article numbere0170679
JournalPLoS One
Volume12
Issue number2
DOIs
Publication statusPublished - 2017
Externally publishedYes

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Exercise equipment
exercise equipment
heat stress
Hot Temperature
Stiffness
heat
Fatigue
Leg
legs
exercise
Skin
Temperature
Thermal comfort
temperature
Fatigue of materials
Recovery
methodology

Cite this

Girard, Olivier ; Brocherie, Franck ; Morin, Jean-Benoit ; Racinais, Sébastien ; Millet, Grégoire P. ; Périard, Julien D. / Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. In: PLoS One. 2017 ; Vol. 12, No. 2.
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title = "Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress",
abstract = "Purpose Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions. Methods 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. Constantvelocity running for 1-min at 10 and 20 km.h -1 was also performed prior to and following sprinting. Results: 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. Conclusions: Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constantvelocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations.",
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Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. / Girard, Olivier; Brocherie, Franck; Morin, Jean-Benoit; Racinais, Sébastien; Millet, Grégoire P.; Périard, Julien D.

In: PLoS One, Vol. 12, No. 2, e0170679, 2017.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress

AU - Girard, Olivier

AU - Brocherie, Franck

AU - Morin, Jean-Benoit

AU - Racinais, Sébastien

AU - Millet, Grégoire P.

AU - Périard, Julien D

PY - 2017

Y1 - 2017

N2 - Purpose Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions. Methods 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. Constantvelocity running for 1-min at 10 and 20 km.h -1 was also performed prior to and following sprinting. Results: 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. Conclusions: Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constantvelocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations.

AB - Purpose Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions. Methods 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. Constantvelocity running for 1-min at 10 and 20 km.h -1 was also performed prior to and following sprinting. Results: 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. Conclusions: Thermal strain alters step frequency and vertical stiffness during repeated sprinting; however without exacerbating mechanical alterations. The absence of changes in constantvelocity running patterns suggests a strong link between fatigue-induced velocity decrements during sprinting and mechanical alterations.

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U2 - 10.1371/journal.pone.0170679

DO - 10.1371/journal.pone.0170679

M3 - Article

VL - 12

JO - PLoS One

JF - PLoS One

SN - 1932-6203

IS - 2

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