skeletal muscle phenotype and performance of an …...athletes muscle characteristics at the...
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![Page 1: Skeletal Muscle Phenotype and Performance of an …...athletes muscle characteristics at the cellular level. The purpose of this study was to determine the myocellular phenotype [fiber](https://reader036.vdocument.in/reader036/viewer/2022070812/5f0bf93f7e708231d433229a/html5/thumbnails/1.jpg)
ABSTRACT
Purpose: Mixed martial arts (MMA) requires a unique combination of muscular
strength, power, and endurance. However, little is known regarding elite MMA
athletes muscle characteristics at the cellular level. The purpose of this study was
to determine the myocellular phenotype [fiber type, size, and myonuclear domain
(MND) size] and whole muscle performance of an elite MMA fighter. Methods:
One male MMA athlete [Record: 8 wins, 2 losses; Ranked: top 10 in the Ultimate
Fighting Championship (UFC) Light Heavyweight Division] volunteered to
participate in this study [Age: 33 y, Height: 1.89 m, Mass: 102.1 kg (competes at
93.0 kg)]. The participant underwent a vastus lateralis muscle biopsy to analyze
myocellular characteristics, which included myosin heavy chain (MHC) fiber type
distribution (via SDS-PAGE), fiber size (cross-sectional area; CSA), and MND size
(via immunofluorescent labeling and confocal microscopy). Whole muscle
performance measures included hand grip dynamometry, peak isometric mid-thigh
pulls, vertical jump (measured with no counter-movement), and 5 repeat Wingate
Anaerobic Tests (WAnT). Results: Muscle fiber type composition was 29% MHC I
(pure slow-twitch fibers), 66% MHC IIa (pure fast-twitch fibers) and 5% hybrid
fibers (containing multiple MHC types). Mean ± SE fiber CSA and MND size were
3,183 ± 225 m² and 11,008 ± 1,331 m³, respectively. His grip strength was 78.4 kg,
isometric mid-thigh pull peak force was 37.7 N/kg, and vertical jump was 57.2 cm.
Additionally, the WAnT determined his peak power (PP): 1,075.89 W, relative PP:
10.45 W/kg, average power (AP): 838.87 W, fatigue index: 43.39%, and PP
decrease over 5 rounds: 12.1%. Conclusion: This elite MMA athlete exhibited a
homogeneous muscle fiber type (i.e. predominantly fast-twitch with few hybrids)
with relatively small MND sizes compared to untrained men in the literature (using
similar measures). These cellular characteristics may help partially explain the
athletes elevated whole muscle strength, power, and endurance performance. This
case study provides initial insight into the muscle physiology of high-level MMA
fighters; future research should continue investigating the myocellular
structure/function relationship among these unique athletes to further our
knowledge regarding elite human muscle physiology.
METHODS
Skeletal Muscle Phenotype and Performance of an
Elite Mixed Martial Artist
1 Muscle Physiology Laboratory, Department of Kinesiology, College of Health & Social Sciences, San Francisco State University
2 Biochemistry & Molecular Exercise Physiology Laboratory, Center for Sport Performance, California State University, Fullerton
CONCLUSIONRESULTS
CONTACT
PARTICIPANT
James R. Bagley1, Jose A. Arevalo2, Kylie K. Malyszek2, Jennifer A. Spencer2, Jakob Rosengarten2,
Saldiam R. Barillas2, Whitney D. Leyva2, Ryan T. McManus2, David Lee2, and Andrew J. Galpin2
Elite Male Mixed Martial Artist
Age: 33 y
Height 1.89 m
Mass: 102.1 kg
Competes at: 93.0 kg
MMA RECORD
8 wins; 2 losses
UFC RANKING
Top 10 in the Light
Heavyweight Division
Myocellular Structural Characteristics
Whole Muscle Functional Performance
Vastus Lateralis Biopsy
Single Fiber Isolation
MHC Fiber Type Continuum
Fluorescence Labeling
• Actin: Alexa Fluor 568 Phalloidin
• Myonuclei: DAPI
Laser Scanning Confocal Microscopy
Hand Grip Dynamometry Peak Isometric Mid-thigh Pulls Vertical Jump Height Wingate Anaerobic Power Test
Single Fiber Myosin Heavy Chain (MHC)
Determination via SDS-PAGE
Muscle Fiber Size and Myonuclei Content
Adapted from Bagley et al. 2012
This MMA fighter’s muscle exhibited:
• A homogenous muscle fiber type (66% MHC IIa
and 5% total hybrids)
• A small MND size, which may be related to
myocellular transport and repair efficiency
• High whole muscle peak power and only a 20%
drop in power over five rounds of Wingate Tests
Myosin Heavy Chain (MHC) Fiber Type Myonuclear Domain (MND) Size Whole Muscle Performance
Dr. Jimmy Bagley Email: [email protected]
@DrJimmy Bagley
Dr. Andy GalpinEmail: [email protected]
@DrAndyGalpin
MHC
Metabolism
Twitch
I I/IIa IIa IIa/IIx IIx
Slow
Oxidative Glycolytic
Fast
0
10
20
30
40
50
60
70
I I/IIa IIa IIa/IIx IIx TotalHybrids
% D
istr
ibu
tio
n
MHC Isoform
Elite MMA Fighter (n=149 fibers)
Sedentary Males (Klitgaard et al. 1990)
Untrained Males (Williamson et al. 2001)
Rec. Active Males (Kohn et al. 2007)
0
10000
20000
30000
40000
50000
MND Size (µm3)0
10
20
30
40
50
MN
D S
ize
(µ
m3;
x10
4)
Elite MMA
Fighter
n = 4 Fibers Analyzed
(sarcomere length
correction to 2.8 um)
Mean
MN
D R
an
ge
Mean MND Range
from Untrained Men
(~22-47.4 µm3; x104)
Liu et al. 2009
Cristea et al. 2010
Qaisar et al. 2011
Single Muscle Fiber
Myo
nu
cle
i
www.musclephyslab.com
@musclephyslab
5
6
7
8
9
10
11
12
Pat
Re
lati
ve P
eak P
ow
er
(W/k
g)
Repeated Wingate Tests (Rounds 1-5)
12.1% Drop in Power
Round
1 2 3 4 5
WINGATE ANAEROBIC
CYCLING TEST
Peak Power
1,075.89 W
Relative Peak Power
10.45 W·kg-1
Fatigue Index
43.39 %
His elevated whole muscle function may be partially explained by his unique
myocellular phenotype. Future research should continue to investigate the muscle
cell structure/function relationship among these unique athletes to further our
knowledge regarding elite human muscle physiology.
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