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High content of MYHC II in vastus lateralis is accompanied by higher VO2/power output ratio during moderate intensity cycling performed both at low and at high pedalling rates.
J Physiol Pharmacol 2006; 57(2):199-215JP

Abstract

The aim of this study was to examine the relationship between the content of various types of myosin heavy chain isoforms (MyHC) in the vastus lateralis muscle and pulmonary oxygen uptake during moderate power output incremental exercise, performed at low and at high pedalling rates. Twenty one male subjects (mean +/- SD) aged 24.1 +/- 2.8 years; body mass 72.9 +/- 7.2 kg; height 179.1 +/- 4.8 cm; BMI 22.69 +/- 1.89 kg.m(-2); VO2max 50.6 +/- 5.3 ml.kg.min(-1), participated in this study. On separate days, they performed two incremental exercise tests at 60 rev.min(-1) and at 120 rev.min(-1), until exhaustion. Gas exchange variables were measured continuously breath by breath. Blood samples were taken for measurements of plasma lactate concentration prior to the exercise test and at the end of each step of the incremental exercise. Muscle biopsies were taken from the vastus lateralis muscle, using Bergström needle, and they were analysed for the content of MyHC I and MyHC II using SDS--PAGE and two groups (n=7, each) were selected: group H with the highest content of MyHC II (60.7 % +/- 10.5 %) and group L with the lowest content of MyHC II (27.6 % +/- 6.1 %). We have found that during incremental exercise at the power output between 30-120 W, performed at 60 rev.min(-1), oxygen uptake in the group H was significantly greater than in the group L (ANCOVA, p=0.003, upward shift of the intercept in VO2/power output relationship). During cycling at the same power output but at 120 rev.min(-1), the oxygen uptake was also higher in the group H, when compared to the group L (i.e. upward shift of the intercept in VO2/power output relationship, ANCOVA, p=0.002). Moreover, the increase in pedalling rate from 60 to 120 rev.min(-1) was accompanied by a significantly higher increase of oxygen cost of cycling and by a significantly higher plasma lactate concentration in subjects from group H. We concluded that the muscle mechanical efficiency, expressed by the VO2/PO ratio, during cycling in the range of power outputs 30-120 W, performed at 60 as well as 120 rev.min(-1), is significantly lower in the individuals with the highest content of MyHC II, when compared to the individuals with the lowest content of MyHC II in the vastus lateralis.

Authors+Show Affiliations

Department of Muscle Physiology, AWF--Kraków, Poland.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Clinical Trial
Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

16845226

Citation

Majerczak, J, et al. "High Content of MYHC II in Vastus Lateralis Is Accompanied By Higher VO2/power Output Ratio During Moderate Intensity Cycling Performed Both at Low and at High Pedalling Rates." Journal of Physiology and Pharmacology : an Official Journal of the Polish Physiological Society, vol. 57, no. 2, 2006, pp. 199-215.
Majerczak J, Szkutnik Z, Karasinski J, et al. High content of MYHC II in vastus lateralis is accompanied by higher VO2/power output ratio during moderate intensity cycling performed both at low and at high pedalling rates. J Physiol Pharmacol. 2006;57(2):199-215.
Majerczak, J., Szkutnik, Z., Karasinski, J., Duda, K., Kolodziejski, L., & Zoladz, J. A. (2006). High content of MYHC II in vastus lateralis is accompanied by higher VO2/power output ratio during moderate intensity cycling performed both at low and at high pedalling rates. Journal of Physiology and Pharmacology : an Official Journal of the Polish Physiological Society, 57(2), pp. 199-215.
Majerczak J, et al. High Content of MYHC II in Vastus Lateralis Is Accompanied By Higher VO2/power Output Ratio During Moderate Intensity Cycling Performed Both at Low and at High Pedalling Rates. J Physiol Pharmacol. 2006;57(2):199-215. PubMed PMID: 16845226.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - High content of MYHC II in vastus lateralis is accompanied by higher VO2/power output ratio during moderate intensity cycling performed both at low and at high pedalling rates. AU - Majerczak,J, AU - Szkutnik,Z, AU - Karasinski,J, AU - Duda,K, AU - Kolodziejski,L, AU - Zoladz,J A, PY - 2006/02/02/received PY - 2006/04/28/accepted PY - 2006/7/18/pubmed PY - 2006/8/30/medline PY - 2006/7/18/entrez SP - 199 EP - 215 JF - Journal of physiology and pharmacology : an official journal of the Polish Physiological Society JO - J. Physiol. Pharmacol. VL - 57 IS - 2 N2 - The aim of this study was to examine the relationship between the content of various types of myosin heavy chain isoforms (MyHC) in the vastus lateralis muscle and pulmonary oxygen uptake during moderate power output incremental exercise, performed at low and at high pedalling rates. Twenty one male subjects (mean +/- SD) aged 24.1 +/- 2.8 years; body mass 72.9 +/- 7.2 kg; height 179.1 +/- 4.8 cm; BMI 22.69 +/- 1.89 kg.m(-2); VO2max 50.6 +/- 5.3 ml.kg.min(-1), participated in this study. On separate days, they performed two incremental exercise tests at 60 rev.min(-1) and at 120 rev.min(-1), until exhaustion. Gas exchange variables were measured continuously breath by breath. Blood samples were taken for measurements of plasma lactate concentration prior to the exercise test and at the end of each step of the incremental exercise. Muscle biopsies were taken from the vastus lateralis muscle, using Bergström needle, and they were analysed for the content of MyHC I and MyHC II using SDS--PAGE and two groups (n=7, each) were selected: group H with the highest content of MyHC II (60.7 % +/- 10.5 %) and group L with the lowest content of MyHC II (27.6 % +/- 6.1 %). We have found that during incremental exercise at the power output between 30-120 W, performed at 60 rev.min(-1), oxygen uptake in the group H was significantly greater than in the group L (ANCOVA, p=0.003, upward shift of the intercept in VO2/power output relationship). During cycling at the same power output but at 120 rev.min(-1), the oxygen uptake was also higher in the group H, when compared to the group L (i.e. upward shift of the intercept in VO2/power output relationship, ANCOVA, p=0.002). Moreover, the increase in pedalling rate from 60 to 120 rev.min(-1) was accompanied by a significantly higher increase of oxygen cost of cycling and by a significantly higher plasma lactate concentration in subjects from group H. We concluded that the muscle mechanical efficiency, expressed by the VO2/PO ratio, during cycling in the range of power outputs 30-120 W, performed at 60 as well as 120 rev.min(-1), is significantly lower in the individuals with the highest content of MyHC II, when compared to the individuals with the lowest content of MyHC II in the vastus lateralis. SN - 0867-5910 UR - https://www.unboundmedicine.com/medline/citation/16845226/High_content_of_MYHC_II_in_vastus_lateralis_is_accompanied_by_higher_VO2/power_output_ratio_during_moderate_intensity_cycling_performed_both_at_low_and_at_high_pedalling_rates_ DB - PRIME DP - Unbound Medicine ER -