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Single muscle fiber myosin heavy chain distribution in elite female track athletes.
Med Sci Sports Exerc. 2003 Mar; 35(3):434-8.MS

Abstract

PURPOSE

Myosin heavy chain (MHC) characterization of tissue samples from the gastrocnemius muscle of six elite female athletes and 10 untrained females was performed using myosin ATPase histochemistry and gel electrophoresis. Athletes were of national and international caliber, whereas their untrained counterparts were healthy individuals not involved in a regular exercise program.

METHODS

Muscle biopsies for the athletes were performed 14 wk into their training season and analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and myosin ATPase techniques.

RESULTS

Electrophoretic analysis of single muscle fibers from elite athletes revealed a MHC phenotype composition of 46 +/- 6% type I, 21 +/- 6% type IIa, and 0% type IIx, whereas 34% of the single fibers expressed multiple MHC isoforms. When compared with the elite women, untrained subjects demonstrated higher percentages of type I MHC and lower percentages of IIa MHC muscle fibers, 57 +/- 5 and 16 +/- 3%, respectively (P < 0.05). Similar to the female athletes, 27% of the fibers from untrained women possessed multiple myosin isoforms. Myosin ATPase staining demonstrated a greater percentage of type I fibers in untrained subjects versus the elite women (67 +/- 3 vs 41 +/- 2%, P< 0.05) (mean +/- SE), whereas the athletes had a higher percentage of type IIa fibers compared with the untrained women (49 +/- 5 vs 19 +/- 2%, P< 0.05). There were no differences in the percentage of IIb fibers between elite and untrained women (11 +/- 4 vs 14 +/- 2%, respectively).

CONCLUSIONS

Whereas a preponderance of hybrid fibers is generally observed in untrained populations, the diverse MHC phenotype seen in these elite female athletes is uncommon. These unique findings are attributed to the chronic and varied nature of training in which these athletes were involved.

Authors+Show Affiliations

Human Performance Research Center, Brigham Young University, Provo, UT 84602, USA. allen_parcell@byu.eduNo affiliation info availableNo affiliation info available

Pub Type(s)

Comparative Study
Journal Article

Language

eng

PubMed ID

12618572

Citation

Parcell, Allen C., et al. "Single Muscle Fiber Myosin Heavy Chain Distribution in Elite Female Track Athletes." Medicine and Science in Sports and Exercise, vol. 35, no. 3, 2003, pp. 434-8.
Parcell AC, Sawyer RD, Craig Poole R. Single muscle fiber myosin heavy chain distribution in elite female track athletes. Med Sci Sports Exerc. 2003;35(3):434-8.
Parcell, A. C., Sawyer, R. D., & Craig Poole, R. (2003). Single muscle fiber myosin heavy chain distribution in elite female track athletes. Medicine and Science in Sports and Exercise, 35(3), 434-8.
Parcell AC, Sawyer RD, Craig Poole R. Single Muscle Fiber Myosin Heavy Chain Distribution in Elite Female Track Athletes. Med Sci Sports Exerc. 2003;35(3):434-8. PubMed PMID: 12618572.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Single muscle fiber myosin heavy chain distribution in elite female track athletes. AU - Parcell,Allen C, AU - Sawyer,Robert D, AU - Craig Poole,R, PY - 2003/3/6/pubmed PY - 2003/7/18/medline PY - 2003/3/6/entrez SP - 434 EP - 8 JF - Medicine and science in sports and exercise JO - Med Sci Sports Exerc VL - 35 IS - 3 N2 - PURPOSE: Myosin heavy chain (MHC) characterization of tissue samples from the gastrocnemius muscle of six elite female athletes and 10 untrained females was performed using myosin ATPase histochemistry and gel electrophoresis. Athletes were of national and international caliber, whereas their untrained counterparts were healthy individuals not involved in a regular exercise program. METHODS: Muscle biopsies for the athletes were performed 14 wk into their training season and analyzed with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and myosin ATPase techniques. RESULTS: Electrophoretic analysis of single muscle fibers from elite athletes revealed a MHC phenotype composition of 46 +/- 6% type I, 21 +/- 6% type IIa, and 0% type IIx, whereas 34% of the single fibers expressed multiple MHC isoforms. When compared with the elite women, untrained subjects demonstrated higher percentages of type I MHC and lower percentages of IIa MHC muscle fibers, 57 +/- 5 and 16 +/- 3%, respectively (P < 0.05). Similar to the female athletes, 27% of the fibers from untrained women possessed multiple myosin isoforms. Myosin ATPase staining demonstrated a greater percentage of type I fibers in untrained subjects versus the elite women (67 +/- 3 vs 41 +/- 2%, P< 0.05) (mean +/- SE), whereas the athletes had a higher percentage of type IIa fibers compared with the untrained women (49 +/- 5 vs 19 +/- 2%, P< 0.05). There were no differences in the percentage of IIb fibers between elite and untrained women (11 +/- 4 vs 14 +/- 2%, respectively). CONCLUSIONS: Whereas a preponderance of hybrid fibers is generally observed in untrained populations, the diverse MHC phenotype seen in these elite female athletes is uncommon. These unique findings are attributed to the chronic and varied nature of training in which these athletes were involved. SN - 0195-9131 UR - https://www.unboundmedicine.com/medline/citation/12618572/Single_muscle_fiber_myosin_heavy_chain_distribution_in_elite_female_track_athletes_ L2 - https://doi.org/10.1249/01.MSS.0000053735.99344.C0 DB - PRIME DP - Unbound Medicine ER -