Carleigh H. Boone, Maren S. Fragala, Tyler C. Scanlon, Nadia S. Emerson, Kyle S. Beyer, Gabriel J. Pruna, Adam J. Wells, Leonardo P. Oliveira, Jeffrey R. Stout, FACSM and Jay R. Hoffman, FACSM
Institute of Exercise Physiology and Wellness, University of Central Florida, Orlando, FL, USA
INTRODUCTION
• Muscle quality (MQ) has been shown to be more closely related to physical
functioning than muscle quantity or mass in older adults.
• MQ can be analyzed non-invasively with ultrasonography (US) to assess
muscle architectural characteristics and echo-intensity (EI), a value that
represents the amount of intramuscular connective tissue and adipose
tissue.
• Echo-intensity values are quantified in arbitrary units of a scale from 0-255.
• An increased EI is indicative of increased amounts of connective and
adipose tissue within the muscle, and thus decreased levels of strength,
power, and functional capacity.
• In a prior study, a negative correlation was found between echo-intensity
values and strength in older males (Fukumoto, et al. 2012)
RESULTS cont’d.
METHODS cont’d.
Ultrasound Muscle Quality & Leg Strength
• Twenty-six healthy older adults (13 male, 13 female; age: 71.0 ± 6.5 y; BMI:
27.5 ± 4.8 kg∙m-2)
• Each participant voluntarily completed an individualized bilateral leg-extension
multiple-repetition maximum (RM) test to measure muscular strength. In
addition, each subject performed a hand grip dynamometer test, and gait
speed and chair rise time exercises to quantify muscle function.
• CROSS-SECTIONAL AREA of the RF and VL was quantified through
analysis of three separate images of each muscle from which an average was
derived (Koppenhaver, et al. 2009). The transducer was positioned
perpendicular to the muscle tissue interface. Scans were conducted using LV
(logiq view) mode ultrasonography.
• ECHO-INTENSITY values were measured using the same images as for CSA
of the RF and VL. Grayscale analysis was performed using ImageJ (National
Institute of Health, USA) to determine EI.
Ultrasound
image of the
dominant leg
Rectus
Femoris.
Crosssectional
area outlined
in yellow.
• LEG STRENGTH was assessed on a seated leg extension machine using a
submaximal protocol. Each subject began with a relatively light load to warm
up. During the test, all participants were asked to complete as many repetitions
as possible prior to fatigue. Their testing weight was determined to allow
completion of 5 to 10 repetitions until volitional fatigue. Strength levels were
estimated using the Brzycki equation to predict maximal strength from
submaximal effort (McNair, et al. 2011).
0
10
20
30
40
50
60
70
Ultrasound MQ
*p = 0.010
Ultrasound Muscle Quality & Gait Speed
Ultrasound MQ & Gait Speed
3
2.5
2
1.5
1
0.5
0
10
20
30
40
50
60
70
Ultrasound MQ
• CHAIR RISE TEST was performed to assess functional mobility. Each
participant was instructed to stand five consecutive times from a seated
position as quickly as possible with arms folded across his/her chest to ensure
the exercise was unassisted. Their time was measured in seconds (s) using a
stopwatch from each participant’s initial movement until their last repetition was
completed.
• HAND GRIP STRENGTH was assessed using a hand-grip dynamometer.
Each participant performed 2 five-second grip tests from which an average
was computed and recorded in kilograms (kg).
*p= 0.007
RESULTS
• MQ of the vastus lateralis significantly correlated to RM (r = 0.529, p =
0.006), HG (r = 0.721, p = 0.000), GS (r = 0.609, p = 0.003), and CRT (r = 0.416, p = 0.039).
• MQ of the rectus femoris significantly correlated to RM (r = 0.505, p = 0.010)
and HG (r = 0.676, p = 0.000).
• Combined thigh MQ significantly correlated to RM (r = 0.503, p = 0.010), HG
(r = 0.801, p = 0.000), and GS (r = 0.554, p = 0.007).
Mean values of Measures of Muscular Strength & Function
• GAIT SPEED was examined with the completion of an 8-foot walk test. During
the assessment, each participant was instructed to walk at his/her normal pace
through an 8-foot course that was previously marked off with tape. With the
use of Brower Infrared Timing Systems, the timer began automatically when
the participant stepped across the starting line and stopped when one foot
completely crossed the finish line. Participants completed 2 trials. Their times
were recorded to the nearest one hundredth of a second.
Measure
Mean ± SD
Leg Extension Rep Max (kg)
77.7 ± 31.7
Hand Grip Strength (kg)
33.5 ± 12.5
Gait Speed (m·s-1)
1.4 ± 0.4
Chair Rise Time (s)
13.7 ± 2.6
• Cross-sectional area (CSA) and echo-intensity (EI) of the vastus lateralis (VL)
and rectus femoris (RF) were quantified through the use of ultrasonography
(Figure 1). A 12MHz linear probe scanning head (General Electric LOGIQ P5,
Wauwatosa, WI, USA) with a gain of 50dB, dynamic range of 72, and depth of
5 cm was used to optimize spatial resolution.
• Individual leg MQ was determined as CSA relative to EI. Ultrasound MQ was
determined as combined thigh CSA multiplied by the sum of combined thigh
EI, shown as (CSA RF + CSA VL) X (EI RF + EI VL). The relationship between
muscle qualitative variables and muscular strength and function were
evaluated using Pearson product moment coefficients.
60
50
40
30
20
10
0
0
10
20
30
40
50
SUMMARY & CONCLUSIONS
• Results suggest that MQ of the VL and RF as assessed through US relates to
muscle strength and function in older adults.
• Interventions that can improve MQ may have functional benefits for older
adults, which may improve the ability to perform activities of daily living.
An ultrasound of a
participant’s
Rectus Femoris
using GE LOGIQ
P5 imaging
REFERENCES
Ultrasound Muscle Quality & Grip Strength
Grip Strength (kg)
Bilateral Leg-Extension MultiRepetition Test
180
160
140
120
100
80
60
40
20
0
0
PURPOSE
• To examine the relationship between ultrasound MQ and measures of muscle
strength and function in older adults.
Leg Extension RM
(kg)
Muscle quality (MQ) has been shown to be more closely
related to physical functioning than muscle quantity or mass in older adults. MQ
can be analyzed non-invasively with ultrasonography (US) to assess muscle
architectural characteristics and echo-intensity (EI), a value that measures the
reflectivity of intramuscular connective tissue. However, it is not known how MQ
analyzed with US relates to muscular strength and function in older adults.
To examine the relationship between ultrasound MQ and measures
of muscle strength and function in older adults.
Twenty-six healthy older adults (13 male, 13 female; 71.0 ± 6.5 y;
27.5 ± 4.8 kg∙m-2) were recruited for this study. Muscle strength was assessed
by an individualized bilateral leg-extension multiple-repetition maximum (RM)
test. Muscle function was assessed using hand grip dynamometer (HG), gait
speed (GS), and chair rise time (CRT). Cross-sectional area (CSA) and EI of
the vastus lateralis (VL) and rectus femoris (RF) were measured using US. MQ
was determined as CSA relative to EI. The relationship between muscle
qualitative variables and muscular strength and function were evaluated using
Pearson product moment coefficients.
Muscle strength and function were RM = 77.7 ± 31.7 kg, HG = 33.5
± 12.5 kg, GS = 1.4 ± 0.4 m·s-1, CRT = 13.7 ± 2.6 s. MQ of the vastus lateralis
significantly correlated to RM (r = 0.529, p = 0.006), HG (r = 0.721, p = 0.000),
GS (r = 0.609, p = 0.003), and CRT (r = -0.416, p = 0.039). MQ of the rectus
femoris significantly correlated to RM (r = 0.505, p = 0.010) and HG (r = 0.676,
p = 0.000). Combined thigh MQ significantly correlated to RM (r = 0.503, p =
0.010), HG (r = 0.801, p = 0.000), and GS (r = 0.554, p = 0.007).
Results suggest that MQ of the VL and RF as assessed
through US relates to muscle strength and function in older adults.
Interventions that can improve MQ may have functional benefits for older
adults, which may improve the ability to perform activities of daily living.
METHODS
Gait Speed (m·s-1)
ABSTRACT
60
Ultrasound MQ
*p = 0.000
70
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