Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress.
<h4>Purpose</h4>Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions.<h4>Methods</h4>Eleven recreationally active males performed a 30-min warm-up followed by three sets of five 5-s sprints with 25-s...
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| Language: | English |
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Public Library of Science (PLoS)
2017-01-01
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| Series: | PLoS ONE |
| Online Access: | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0170679&type=printable |
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| author | Olivier Girard Franck Brocherie Jean-Benoit Morin Sébastien Racinais Grégoire P Millet Julien D Périard |
| author_facet | Olivier Girard Franck Brocherie Jean-Benoit Morin Sébastien Racinais Grégoire P Millet Julien D Périard |
| author_sort | Olivier Girard |
| collection | DOAJ |
| description | <h4>Purpose</h4>Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions.<h4>Methods</h4>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.<h4>Results</h4>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.<h4>Conclusions</h4>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. |
| first_indexed | 2024-12-21T10:53:27Z |
| format | Article |
| id | doaj.art-3bad571b62a54a4d8aa9462b9798acbe |
| institution | Directory Open Access Journal |
| issn | 1932-6203 |
| language | English |
| last_indexed | 2025-03-14T14:16:08Z |
| publishDate | 2017-01-01 |
| publisher | Public Library of Science (PLoS) |
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| spelling | doaj.art-3bad571b62a54a4d8aa9462b9798acbe2025-02-27T05:33:51ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01122e017067910.1371/journal.pone.0170679Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress.Olivier GirardFranck BrocherieJean-Benoit MorinSébastien RacinaisGrégoire P MilletJulien D Périard<h4>Purpose</h4>Examine the mechanical alterations associated with repeated treadmill sprinting performed in HOT (38°C) and CON (25°C) conditions.<h4>Methods</h4>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.<h4>Results</h4>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.<h4>Conclusions</h4>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.https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0170679&type=printable |
| spellingShingle | Olivier Girard Franck Brocherie Jean-Benoit Morin Sébastien Racinais Grégoire P Millet Julien D Périard Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. PLoS ONE |
| title | Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. |
| title_full | Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. |
| title_fullStr | Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. |
| title_full_unstemmed | Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. |
| title_short | Mechanical Alterations Associated with Repeated Treadmill Sprinting under Heat Stress. |
| title_sort | mechanical alterations associated with repeated treadmill sprinting under heat stress |
| url | https://journals.plos.org/plosone/article/file?id=10.1371/journal.pone.0170679&type=printable |
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