Relationship between muscle oxygenation kinetics and the rate of decline in peak torque during isokinetic knee extension in acute hypoxia and normoxia

Yoyoi Kawahara, Y. Salto, K. Kashimura, Isao Muraoka

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

To investigate whether low FiO2 affects muscle oxygenation and the rate of decline in peak torque (DR) during isokinetic knee extension, subjects performed 50 isokinetic knee extensions at 180°/s and at 0.5 Hz while inhaling low O2 gas (12%O2; H) or air (N). Muscle oxygenation kinetics was assessed by near-infrared spectroscopy, and wholebody V̇O2 and HR were measured. We calculated total-, oxy- and deoxy-hemoglobin/myoglobin concentrations (TotalHb/Mb, OxyHb/Mb, DeoxyHb/Mb), and the slopes of the change in OxyHb/Mb during exercise. SpO2 decreased in H while DR and V̇O2 did not differ between the conditions. During exercise, OxyHb/Mb was lower in H than in N, and DeoxyHb/Mb was higher in H than in N. TotalHb/Mb began to increase from the resting level earlier in H. HR was higher during the latter half of the exercise in H. The slopes of the change in OxyHb/Mb were the same in the two conditions. Our results show that low FiO2 decreases SpO2 and muscle oxygenation during maximal isokinetic knee extension. However, low SpO 2 and muscle oxygenation did not affect the rates of decline of peak torque. These results suggest that the decline in peak torque occurs for reasons other than O2 availability.

Original languageEnglish
Pages (from-to)379-383
Number of pages5
JournalInternational Journal of Sports Medicine
Volume29
Issue number5
DOIs
Publication statusPublished - 2008 May

Fingerprint

Torque
Knee
Muscles
Hemoglobins
Near-Infrared Spectroscopy
Myoglobin
Inhalation
Gases
Air
Hypoxia

Keywords

  • Hypoxia
  • Isokinetic knee extension
  • Near-infrared spectroscopy
  • Oxygenation

ASJC Scopus subject areas

  • Public Health, Environmental and Occupational Health
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Relationship between muscle oxygenation kinetics and the rate of decline in peak torque during isokinetic knee extension in acute hypoxia and normoxia. / Kawahara, Yoyoi; Salto, Y.; Kashimura, K.; Muraoka, Isao.

In: International Journal of Sports Medicine, Vol. 29, No. 5, 05.2008, p. 379-383.

Research output: Contribution to journalArticle

@article{e0c2a203b0704c338e70073d760dd7c9,
title = "Relationship between muscle oxygenation kinetics and the rate of decline in peak torque during isokinetic knee extension in acute hypoxia and normoxia",
abstract = "To investigate whether low FiO2 affects muscle oxygenation and the rate of decline in peak torque (DR) during isokinetic knee extension, subjects performed 50 isokinetic knee extensions at 180°/s and at 0.5 Hz while inhaling low O2 gas (12{\%}O2; H) or air (N). Muscle oxygenation kinetics was assessed by near-infrared spectroscopy, and wholebody V̇O2 and HR were measured. We calculated total-, oxy- and deoxy-hemoglobin/myoglobin concentrations (TotalHb/Mb, OxyHb/Mb, DeoxyHb/Mb), and the slopes of the change in OxyHb/Mb during exercise. SpO2 decreased in H while DR and V̇O2 did not differ between the conditions. During exercise, OxyHb/Mb was lower in H than in N, and DeoxyHb/Mb was higher in H than in N. TotalHb/Mb began to increase from the resting level earlier in H. HR was higher during the latter half of the exercise in H. The slopes of the change in OxyHb/Mb were the same in the two conditions. Our results show that low FiO2 decreases SpO2 and muscle oxygenation during maximal isokinetic knee extension. However, low SpO 2 and muscle oxygenation did not affect the rates of decline of peak torque. These results suggest that the decline in peak torque occurs for reasons other than O2 availability.",
keywords = "Hypoxia, Isokinetic knee extension, Near-infrared spectroscopy, Oxygenation",
author = "Yoyoi Kawahara and Y. Salto and K. Kashimura and Isao Muraoka",
year = "2008",
month = "5",
doi = "10.1055/s-2007-965567",
language = "English",
volume = "29",
pages = "379--383",
journal = "International Journal of Sports Medicine",
issn = "0172-4622",
publisher = "Georg Thieme Verlag",
number = "5",

}

TY - JOUR

T1 - Relationship between muscle oxygenation kinetics and the rate of decline in peak torque during isokinetic knee extension in acute hypoxia and normoxia

AU - Kawahara, Yoyoi

AU - Salto, Y.

AU - Kashimura, K.

AU - Muraoka, Isao

PY - 2008/5

Y1 - 2008/5

N2 - To investigate whether low FiO2 affects muscle oxygenation and the rate of decline in peak torque (DR) during isokinetic knee extension, subjects performed 50 isokinetic knee extensions at 180°/s and at 0.5 Hz while inhaling low O2 gas (12%O2; H) or air (N). Muscle oxygenation kinetics was assessed by near-infrared spectroscopy, and wholebody V̇O2 and HR were measured. We calculated total-, oxy- and deoxy-hemoglobin/myoglobin concentrations (TotalHb/Mb, OxyHb/Mb, DeoxyHb/Mb), and the slopes of the change in OxyHb/Mb during exercise. SpO2 decreased in H while DR and V̇O2 did not differ between the conditions. During exercise, OxyHb/Mb was lower in H than in N, and DeoxyHb/Mb was higher in H than in N. TotalHb/Mb began to increase from the resting level earlier in H. HR was higher during the latter half of the exercise in H. The slopes of the change in OxyHb/Mb were the same in the two conditions. Our results show that low FiO2 decreases SpO2 and muscle oxygenation during maximal isokinetic knee extension. However, low SpO 2 and muscle oxygenation did not affect the rates of decline of peak torque. These results suggest that the decline in peak torque occurs for reasons other than O2 availability.

AB - To investigate whether low FiO2 affects muscle oxygenation and the rate of decline in peak torque (DR) during isokinetic knee extension, subjects performed 50 isokinetic knee extensions at 180°/s and at 0.5 Hz while inhaling low O2 gas (12%O2; H) or air (N). Muscle oxygenation kinetics was assessed by near-infrared spectroscopy, and wholebody V̇O2 and HR were measured. We calculated total-, oxy- and deoxy-hemoglobin/myoglobin concentrations (TotalHb/Mb, OxyHb/Mb, DeoxyHb/Mb), and the slopes of the change in OxyHb/Mb during exercise. SpO2 decreased in H while DR and V̇O2 did not differ between the conditions. During exercise, OxyHb/Mb was lower in H than in N, and DeoxyHb/Mb was higher in H than in N. TotalHb/Mb began to increase from the resting level earlier in H. HR was higher during the latter half of the exercise in H. The slopes of the change in OxyHb/Mb were the same in the two conditions. Our results show that low FiO2 decreases SpO2 and muscle oxygenation during maximal isokinetic knee extension. However, low SpO 2 and muscle oxygenation did not affect the rates of decline of peak torque. These results suggest that the decline in peak torque occurs for reasons other than O2 availability.

KW - Hypoxia

KW - Isokinetic knee extension

KW - Near-infrared spectroscopy

KW - Oxygenation

UR - http://www.scopus.com/inward/record.url?scp=43949088858&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=43949088858&partnerID=8YFLogxK

U2 - 10.1055/s-2007-965567

DO - 10.1055/s-2007-965567

M3 - Article

C2 - 17879886

AN - SCOPUS:43949088858

VL - 29

SP - 379

EP - 383

JO - International Journal of Sports Medicine

JF - International Journal of Sports Medicine

SN - 0172-4622

IS - 5

ER -