MUSCULAR POWER CORRELATES TO ECHO INTENSITY AND MUSCLE ARCHITECTURE IN NCAA DIVISION I
FEMALE SOCCER PLAYERS
Tyler C. Scanlon, William P. McCormack, Jonathan D. Bohner, Adam J. Wells, Adam R. Jajtner, Jeremy R. Townsend, Nadia S. Emerson, Adam M. Gonzalez, Edward H. Robinson IV, Gabriel J. Pruna, Carleigh H. Boone,
Maren S. Fragala, Jay R. Hoffman FACSM, Jeffery R. Stout FACSM
Human Performance Laboratory, University of Central Florida, Orlando, FL., USA,
ABSTRACT
METHODS
BACKGROUND: High muscular power output is desirable for sport success and is
determined by many collective architectural properties of muscle. Muscle
ultrasonography is often used to non-invasively evaluate muscle architecture through
measures of muscle thickness (MT) and muscle cross-sectional area (CSA). In
addition, recent technological advances in ultrasound measures has provided an
ability to assess muscle quality through echo intensity (EI), in which fibrous tissue
and intramuscular adipose is measured relative to contractile units. To our knowledge
no data exists examining the relationship between power output, muscle architecture
and muscle quality in female college athletes. PURPOSE: To examine the
relationship between lower extremity peak jump power (JP) and measures of muscle
architecture and muscle quality in competitive female soccer players. METHODS:
Peak vertical jump power was assessed in twenty-six division-1 female soccer
players (age: 19.4 ± 1.1; height: 169.3 ± 7.7 cm; weight: 64 ± 6.9 kg). MT, CSA, and
EI of the rectus femoris (RF) and vastus lateralis (VL) were evaluated with
ultrasonography. Relative muscle quality (MQ) and relative thigh muscle quality (tMQ)
were calculated as (EI/CSA) and (RF+VL EI/ RF+VL CSA), respectively. Pearson’s
correlation coefficients were computed to assess the relationship among variables.
RESULTS: Peak vertical jump power demonstrated significant correlations with
vastus lateralis cross-sectional area (VL-CSA), vastus lateralis relative muscle quality
(VL-MQ), as well as tMQ. CONCLUSIONS: Peak jump power was significantly
correlated to vastus lateralis CSA, vastus lateralis relative MQ, and thigh relative MQ
in female soccer athletes. Results suggest that power output is related not only to
muscle CSA, but also muscle quality per unit of muscle mass as assessed by
ultrasonography.
INTRODUCTION
• High muscular power output is desirable for
sport success and is determined by many
collective architectural properties of muscle.
• To our knowledge no data exist examining
the relationship between power output,
muscle architecture and muscle quality in
female college athletes.
PURPOSE
• To examine the relationship between
lower extremity peak jump power
(JP) and measures of muscle
architecture and muscle quality in
competitive female soccer players.
• Muscle Thickness: For measures of MT, the probe was oriented parallel to the
muscle tissue interface. Thickness was measured as the perpendicular distance
from the superficial aponeurosis to the deep aponeurosis.
Study Protocol
Rest 15 Minutes
supine on
examination
table
• Allow for any
fluid shifts to
occur
Ultrasound
• Echo intensity: Echo intensity values were obtained using the same images as
for CSA. EI was determined by grayscale analysis (figure 1) using the standard
histogram function in ImageJ, where an increased value denotes a lower quality,
stemming from a higher acoustical impedance due to an increase in
intramuscular adipose and connective tissue.
• Rectus Femoris
• Vastus Lateralis
• Relative MQ and Thigh
relative MQ calculated
Peak Vertical
Jump Power (w)
• Hands on hips
• Participants rested supine for 15 minutes allowing for any fluid shifts to occur.
*p ≤ .05
r= -.54*
Figure 4. Correlation between peak power
(W) and thigh muscle quality (EI/cm^2).
Figure 1. Echo intensity of the rectus
femoris quantified using grayscale analysis.
r= -.47*
• MT, CSA, and EI of the rectus femoris (RF) and vastus lateralis (VL) were
evaluated with ultrasonography.
*p ≤ .05
• A 12MHz linear probe scanning head (General Electric LOGIQ P5, Wauwatosa, WI,
USA) with a gain of 50 dB, dynamic range of 72, and depth of 5 cm was used to
optimize spatial resolution. The probe was coated with water soluble transmission
gel and positioned on the surface of the skin to provide acoustic contact without
depressing the dermal layer to collect the image.
• For images of VL: Participant placed recumbent on non-dominant leg side with legs
bent at 10 degrees. Toes angled approximately 45 degrees in relation to the frontal
plane. Measurements were taken at 50% of limb length, determined as the midpoint
from the most prominent point of the greater trochanter of the femur to the lateral
epicondyle (Thomaes et al. 2012).
• Relative muscle quality (MQ) and relative thigh muscle quality (tMQ) were
calculated as (EI/CSA) and [(RF EI + VL EI) / (RF CSA + VL CSA)], respectively.
• Peak vertical jump power was assessed via accelerometer fixed with a pelvic strap
and with hands on waist.
• Pearson’s
correlation
coefficients were computed
to assess the relationship
among variables.
Vastus lateralis
Rectus femoris
Collection of muscle architecture
and muscle quality images.
Figure 3. Correlation between peak power
(W) and vastus lateralis muscle quality
(EI/cm^2).
• Peak Vertical Jump Power: Participants were instructed to place hands on hips
while jumping. Body mass was entered in kilograms to calculate power in
wattage. 5 jumps were performed non-consecutively. The highest recorded
wattage was accepted as peak jump power.
• For images of RF: Participant placed supine, with legs extended but relaxed and
toes pointed toward the ceiling. A rolled towel was placed beneath the popliteal
fossa to allow for a 10 degree bend in the knee as measured by goniometer
(Bemben 2002). Measurements were taken at 50% of limb length, determined as
half the distance from the anterior, inferior iliac to the proximal border of the patella.
Peak vertical jump power
assessment using an
accelerometer.
r=.62*
• Cross-sectional area: For measures of CSA, the probe was oriented
perpendicular to the muscle tissue interface. Scans were conducted using LV
(logiq view) mode ultrasonography. The polygon tool was used in ImageJ
(National Institutes of Health, USA, version 1.45s). to outline as much of the
muscle as possible without including any surrounding fascia.
• For each measure, three consecutive images were
captured analyzed
(Koppenhaver et al. 2009). The same investigator performed all ultrasound
measurements. (ICC) for MT was 0.89 (SEM= .12), for CSA ICC was 0.99 (SEM=
1.26), and for EI, ICC was 0.93 (SEM= 5.1).
• Muscle ultrasonography is often used to
non-invasively evaluate muscle architecture
through measures of muscle thickness (MT)
and muscle cross-sectional area (CSA).
• Recent
technological
advances
in
ultrasound measures have provided an
ability to assess muscle quality through
echo intensity (EI), in which fibrous tissue
and intramuscular adipose is measured
relative to contractile tissue.
Measures
Figure 2. Correlation between peak power (W)
and vastus lateralis cross-sectional area (cm^2).
Cross-sectional
sweep of the vastus
lateralis in LV mode.
Hamstrings
Femur
Vastus intermedius
(EI/cm^2)
*p ≤ .05
RESULTS
SUMMARY & CONCLUSIONS
• Peak vertical jump power demonstrated significant correlations with vastus
lateralis cross-sectional area (VL-CSA; figure 2), vastus lateralis relative muscle
quality (VL-MQ; figure 3), as well as tMQ (figure 4).
• The table and figures below present the correlation of jump power to measures
of muscle quality and quantity.
Table 1. Correlation of jump power to measures of muscle quality and quantity.
Measure
Pearson's Correlation Coefficient
P-value
VL- MT
VL- CSA
VL- EI
VL- MQ
RF- MT
RF-CSA
RF- EI
RF- MQ
0.18
0.62*
−0.03
−0.54*
0.18
0.21
0.08
−0.13
0.36
0.00
0.80
0.00
0.36
0.29
0.68
0.52
tMQ
−0.47*
0.01
*significance (p≤.05)
• Peak jump power was significantly correlated to vastus lateralis CSA, vastus
lateralis relative MQ, and thigh relative MQ in female soccer athletes.
• Results suggest that power output is
related not only to muscle CSA, but
also muscle quality per unit of muscle
mass as assessed by ultrasonography.
• Further research is warranted to
investigate the relationship between
muscle quality and various
performance measures including, but
not limited to muscular power in
collegiate female athletes.
Analysis output given as a mean pixel count ranging 0-255 Au.
REFERENCES
Bemben, M.G. Use of Diagnostic Ultrasound for Assessing Muscle Size. Journal of
Strength and Conditioning Research. 16 (1): 103-108, 2002.
Koppenhaver, S.L., Parent, E.C., Teyhen, D.S., Hebert, J.J., Fritz, J.M. The effect of
averaging multiple trials on measurement error during ultrasound imaging of
transverse abdominis and lumbar multifidus muscles in individuals with lower
back pain. Journal of Orthopedic and Sports Physical Therapy. 39 (8): 604-611,
2009.
Thomaes, T., Thomis, M., Onkelinx, S., Coudyzer, W., Cornelissen, V., and Vanhees, L.
Reliability and validity of the ultrasound technique to measure the rectus femoris
muscle diameter in older CAD-patients. BMC Medical Imaging. 12 (7): 2012.