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The isometric torque at which knee-extensor muscle reoxygenation stops.
Med Sci Sports Exerc. 2007 Mar; 39(3):443-53.MS

Abstract

PURPOSE

We investigated the knee-extensor torque at which reoxygenation (inflow of arterial blood) during an isometric contraction stopped, whether this torque depended on maximal torque capacity (MTC), and whether there were differences among the synergists.

METHODS

Isometric knee-extension torque was measured using a dynamometer with 90 degrees angles in the hip and knee. Maximal voluntary activation (established with superimposed nerve stimulation) was > 90% in the 15 healthy male subjects (20-30 yr). Near-infrared spectroscopy (NIRS) was used to measure changes in muscle oxygenation of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscle during submaximal isometric contractions at intensities of 20-45% MTC with 5% increments, applied in randomized order and divided over 2 d. At each torque, a contraction with an inflated pressure cuff (450 mm Hg), inducing full arterial occlusion, was followed (10 min of rest) by a second contraction without the cuff.

RESULTS

MTC ranged from 178 to 348 N.m. The torque at which maximal deoxygenation (all oxygen consumed) during contraction without the cuff became similar (P < 0.05) to the maximal deoxygenation reached with the cuff (indicative for complete occlusion of blood flow during the contraction without the cuff) was significantly higher for the RF (35% MTC) than for both vasti (25% MTC). There was no significant relation between MTC and relative (% MTC) torque at which muscle reoxygenation stopped.

CONCLUSION

Knee-extensor reoxygenation stopped at lower torques than previously reported for blood flow in this muscle, and this occurred at the same % MTC in subjects of different strength but at different % MTC for the different synergists.

Authors+Show Affiliations

Institute for Fundamental and Clinical Human Movement Sciences, Vrije University, Amsterdam, The Netherlands. C_J_de_Ruiter@FBW.VU.NLNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

17473770

Citation

de Ruiter, C J., et al. "The Isometric Torque at Which Knee-extensor Muscle Reoxygenation Stops." Medicine and Science in Sports and Exercise, vol. 39, no. 3, 2007, pp. 443-53.
de Ruiter CJ, Goudsmit JF, Van Tricht JA, et al. The isometric torque at which knee-extensor muscle reoxygenation stops. Med Sci Sports Exerc. 2007;39(3):443-53.
de Ruiter, C. J., Goudsmit, J. F., Van Tricht, J. A., & de Haan, A. (2007). The isometric torque at which knee-extensor muscle reoxygenation stops. Medicine and Science in Sports and Exercise, 39(3), 443-53.
de Ruiter CJ, et al. The Isometric Torque at Which Knee-extensor Muscle Reoxygenation Stops. Med Sci Sports Exerc. 2007;39(3):443-53. PubMed PMID: 17473770.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The isometric torque at which knee-extensor muscle reoxygenation stops. AU - de Ruiter,C J, AU - Goudsmit,Jos F A, AU - Van Tricht,Johannes A, AU - de Haan,Arnold, PY - 2007/5/3/pubmed PY - 2007/6/15/medline PY - 2007/5/3/entrez SP - 443 EP - 53 JF - Medicine and science in sports and exercise JO - Med Sci Sports Exerc VL - 39 IS - 3 N2 - PURPOSE: We investigated the knee-extensor torque at which reoxygenation (inflow of arterial blood) during an isometric contraction stopped, whether this torque depended on maximal torque capacity (MTC), and whether there were differences among the synergists. METHODS: Isometric knee-extension torque was measured using a dynamometer with 90 degrees angles in the hip and knee. Maximal voluntary activation (established with superimposed nerve stimulation) was > 90% in the 15 healthy male subjects (20-30 yr). Near-infrared spectroscopy (NIRS) was used to measure changes in muscle oxygenation of the vastus medialis (VM), vastus lateralis (VL), and rectus femoris (RF) muscle during submaximal isometric contractions at intensities of 20-45% MTC with 5% increments, applied in randomized order and divided over 2 d. At each torque, a contraction with an inflated pressure cuff (450 mm Hg), inducing full arterial occlusion, was followed (10 min of rest) by a second contraction without the cuff. RESULTS: MTC ranged from 178 to 348 N.m. The torque at which maximal deoxygenation (all oxygen consumed) during contraction without the cuff became similar (P < 0.05) to the maximal deoxygenation reached with the cuff (indicative for complete occlusion of blood flow during the contraction without the cuff) was significantly higher for the RF (35% MTC) than for both vasti (25% MTC). There was no significant relation between MTC and relative (% MTC) torque at which muscle reoxygenation stopped. CONCLUSION: Knee-extensor reoxygenation stopped at lower torques than previously reported for blood flow in this muscle, and this occurred at the same % MTC in subjects of different strength but at different % MTC for the different synergists. SN - 0195-9131 UR - https://www.unboundmedicine.com/medline/citation/17473770/The_isometric_torque_at_which_knee_extensor_muscle_reoxygenation_stops_ L2 - https://doi.org/10.1249/mss.0b013e31802dd3cc DB - PRIME DP - Unbound Medicine ER -