Taniguchi et al.
Journal of Physiological Anthropology(2023) 42:14
https://doi.org/10.1186/s40101-023-00331-6

ORIGINAL ARTICLE

Journal of
Physiological Anthropology

Open AccessSitting vs. supine ultrasound measurementsof the vastus medialis: correlations with MRI
measurements and age considerations
Masashi Taniguchi1* , Yoshihiro Fukumoto1,2, Masahide Yagi1, Tetsuya Hirono1,3,4, Momoko Yamagata1,2,
Ryusuke Nakai5, Yosuke Yamada6, Misaka Kimura7 and Noriaki Ichihashi1

Abstract
Background Muscle thickness (MT) and echo intensity (EI) measurements are ultrasound alternatives to magnetic
resonance imaging (MRI) for evaluating muscle quantity and quality. The vastus medialis (VM) is a clinically importantmuscle, and assessment methods that most accurately reflect its quantity and quality are required. This study aimed
to examine the correlation between MT and EI measured in the supine and sitting postures with corresponding MRImeasured muscle quantity and quality indices.
Methods In total, 134 adults (91 older and 43 young) participated in this study. Ultrasound images of the VM wereacquired in the supine and sitting postures, and MT and EI were measured. The cross-sectional area (CSA), muscle volume (MV), and intramuscular adipose tissue (intraMAT) of the VM were evaluated from MRI images using T1-weighted
and Dixon methods. Pearson’s coefficients were used to quantify the correlation strength amongst pairs of dependent
variables. Meng’s test was used to test for correlation coefficient differences between the two measurement postures(supine and sitting).
Results The correlation coefficients amongst MT, CSA, and MV were significantly higher in the sitting posturethan in the supine posture. EI measured in the supine and sitting postures correlated significantly with intraMAT,
and in young individuals, these correlation coefficients were significantly higher in the sitting posture than in thesupine posture.
Conclusions These findings suggest that assessment of VM muscle quantity in the sitting posture is superior
for young and older individuals, and assessment of VM muscle quality in the sitting posture is most effective
in younger individuals.
Keywords Vastus medialis, Measurement posture, Muscle thickness, Echo intensity*Correspondence:
Masashi Taniguchi
taniguchi.masashi.7a@kyoto-u.ac.jp
Full list of author information is available at the end of the article© The Author(s) 2023. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which
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Taniguchi et al. Journal of Physiological Anthropology(2023) 42:14

Introduction
Age-related muscle weakness is associated with atrophy and loss of muscle quality, such as an increase in
intramuscular adipose tissue (intraMAT) infiltration[1–3]. While magnetic resonance imaging (MRI) is thegold standard for quantifying muscle volume (MV) asa quantity index and intraMAT as a quality index, it istime-consuming for acquisition and analysis. B-mode
ultrasound (US) imaging is a convenient, cost-effective,
and noninvasive alternative. Several previous B-mode
US studies [4–8] have used muscle thickness (MT) as amuscle quantity index and muscle echo intensity (EI) as
a muscle quality index. Decrease in MT indicates loss ofmuscle mass, while enhanced EI reflects an increase in
intraMAT infiltration [9, 10]. Although there is no doubtthat muscle mass is larger in men than in women, an
increased intraMAT is not different between sexes [11].
Given that MT and EI are negatively correlated in older
individuals [12], the loss of muscle quantity and quality isrelatively more affected by ageing than by sex [11]. Thus,
assessment of MT and EI may be useful in detecting agerelated changes.
Many studies have focused on degeneration of the vastus medialis (VM) muscle because it has the second largest muscle cross-sectional area (CSA) in the quadriceps
group and because it functions as a dynamic stabilizerof the knee [13–15]. VM assessment is commonly conducted in the supine posture [16–18] with high reproducibility [19]. However, MT and EI measurements canconceivably be influenced by changes in muscle morphology resulting from pressure on the posterior thigh fromthe bed surface while supine. It is also conceivable that
VM morphology changes less while sitting on the edge ofa chair because the pressure on the posterior distal thighis reduced. An additional conceivable advantage of sitting is measurement ease; an examiner can easily operate
the probe to identify the thickest site of the VM. While aprevious study [20] confirmed that differences in measurement posture can change muscle shape, which could
influence both MT and EI, to the best of our knowledge,
no previous report has compared sitting and supine postures in terms of muscle quantity and quality indicators.
Provided one measures a single muscle, EI measurement results are unaffected by measurement location [21]. However, both MT and EI measurements are
expected to be posture dependent because (a) changing from supine to sitting stretches the quadriceps,
implying that the VM’s MT is thinner when sitting thanwhen supine, and (b) MT changes affect echo attenuation, which in turn implies posture-dependent EI. While
posture dependence of absolute MT and EI values is
expected, it is unclear whether their correlations withcorresponding MRI indices are also posture dependent.

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It is also unclear whether these potentially posturedependent correlations are affected by ageing.
This study aimed to examine the correlation between
MT and EI measured in the sitting and supine postureswith their corresponding MRI indicators: CSA, MV,
and intraMAT. Due to more easily identifiable measurement site when sitting, we hypothesized that MT is morestrongly correlated with CSA and MV when sitting thanwhen supine. We also hypothesized that the EI value
measured in the sitting posture was higher than that in
the supine posture because of the thinning of the MT,
and that the correlation between EI and intraMAT in theyoung subgroup was stronger in the sitting posture thanin the supine posture. This verification will help to establish more optimal measurement methods for MT and EI
measurements of the VM using B-mode US images.

Materials and methods
Study participants and procedures

Ninety-one healthy older adults aged > 60 years (women,n = 49 [53.8%]; mean age, 75.3 ± 6.6 [range, 60–89] years)
and 43 healthy young adults (women, n = 21 [48.8%];
mean age, 26.1 ± 4.7 [range, 20–39] years) were enrolled
in this study. The inclusion criteria were as follows: independent community living, no assistive walking devices,no history of lower extremity surgery, and no generalcontraindications for MRI. The exclusion criteria were as
follows: medical history of rheumatoid arthritis, neurological disorders including stroke and Parkinson’s disease,and cognitive dysfunction. Before initiating the examination, the purposes and procedures were explained tothe participants, and they provided written informed
consent. The study protocol was approved by the Ethics Committee of Kyoto University Graduate School andFaculty of Medicine (R1746).
The participants were instructed to avoid excessive
physical activity prior to measurements. Upon arrival at
the laboratory, participants rested in a sitting or supine
posture and were allowed a small amount of water intake.
Ultrasound and MRI measurements were randomly performed on the same day. Before the US and MRI acquisitions, the measurement site of the VM described below
was marked on the skin.
Ultrasound measurements

A real-time B-mode US device (LOGIQ e, GE Healthcare, UK) with an 8–12-MHz linear transducer was used
to acquire transverse images of the VM on the rightthigh. The settings for obtaining US images were unified
for all measurements at a frequency of 8 MHz, dynamic
range of 69 dB, and time gain of 58 dB, The measurementsite was set on the VM muscle area medially displaced
from the 30% distal between the greater trochanter andTaniguchi et al. Journal of Physiological Anthropology(2023) 42:14

Fig. 1 Measurement postures and representative ultrasound imagesof the vastus medialis captured in (i) supine and (ii) sitting postures.
Ultrasound images of the vastus medialis in supine and sitting
postures of young men who participated this study

lateral femoral tuberosity. This VM site has the largest
CSA [22]. The two scanning postures were as follows(Fig. 1): (1) supine posture (the participants laid supine
and relaxed completely, and their knee joints were set in
extension with neutral posture of the hip) and (2) sitting

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posture (the participants were seated on the edge of one’s
chair to avoid contact between the posterior surfaces of
the thighs and chair, with 90° of knee flexion and footon the floor). The contralateral lower leg (hip joint) was
slightly abducted as needed to facilitate transducer use.
The investigator applied the transducer perpendicular to the longitudinal axis of the femur while avoiding
compressive tissue deformation using a water-solubletransmission gel. Subsequently, the investigator carefully
adjusted the transducer to the location of the thickest
MT (i.e. the distance from the subfascia and femur). The
dynamic focus depth was located at the middle of the VM
to consider the effect of depth-dependent attenuation of
the EI [10]. Three investigators with over 5-year experience of US operation conducted these measurements.
MT was measured as the maximum distance from themuscle fascia to the femur. For EI analysis, image analysis
software (ImageJ-WinJP; LISIT, Japan) was used, first toconvert the data to 8-bit greyscale, yielding EI values with
arbitrary units (a.u.) from 0 to 255 (black to white), whereenhanced EI reflected an increase in intraMAT infiltration (Fig. 2) [9]. The region of interest (ROI) was set as
the maximum-sized rectangle that encapsulated the VM
without also encapsulating fascia and bone. The mean EI
was quantified as the average pixel intensity within the
ROI. These analyses of MT and EI were performed by aninvestigator other than the investigator who obtained the
US images. The intraclass correlation coefficient (ICC)(1.1) values for the MT and EI in the supine and sitting
postures were 0.87 and 0.98 and 0.81 and 0.93, respectively. The ICC (2.1) values for the MT and EI in thesupine and sitting postures were 0.81 and 0.83 and 0.76
and 0.81, respectively.

Fig. 2 Representative ultrasound images measured in the sitting posture of A young and B older individuals. The young participant exhibits thick
MT and low EI, while the older participant exhibits thin MT and high EI. The higher density of white values in the older participant reflects increased
intraMAT

Taniguchi et al. Journal of Physiological Anthropology(2023) 42:14

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Table 1 Summary of participant’s characteristics and muscle properties measured using magnetic resonance imaging
Pooledn = 134

Older

Young

Total

Men

Women

Total

Men

Women

n = 91n =40

n = 51n = 43n = 22n = 21Age, years

59.8 ± 23.8

75.4 ± 6.7

76.7 ± 6.2

74.4 ± 7.0

26.1 ± 4.7

27.3 ± 4.4

24.9 ± 4.7

Height, cm

160.7 ± 8.9

158.5 ± 9.0

166.1 ± 6.0

152.1 ± 5.6

165.5 ± 6.6

170.4 ± 4.3

160.4 ± 4.3

Weight, kg

55.3 ± 8.7

54.2 ± 9.0

60.8 ± 7.9

48.8 ± 5.7

57.8 ± 7.7

63.0 ± 5.5

52.5 ± 5.6

Body mass index, kg/m2

21.4 ± 2.4

22.0 ± 2.6

21.1 ± 2.6

21.5 ± 2.6

21.0 ± 1.9

21.7 ± 1.5

20.4 ± 2.2

MV, ­cm3

301.2 ± 98.5

267.9 ± 80.5

325.0 ± 60.7

220.9 ± 62.5

373.2 ± 97.4

451.4 ± 63.7

291.3 ± 43.6

CSA, ­cm2

15.1 ± 4.5

13.8 ± 3.9

16.2 ± 3.5

11.8 ± 3.1

17.9 ± 4.4

21.1 ± 2.9

14.5 ± 2.9

IntraMAT, %6.5 ± 2.1

7.0 ± 2.2

6.5 ± 1.5

7.5 ± 2.7

5.4 ± 1.1

5.1 ± 0.8

5.7 ± 1.4

MRI measurements

Before starting the MRI acquisition, a surface marker
was placed at the US measurement site. T1-weighted
and 2-point Dixon MRIs of the right thigh from the pelvis to the right tibial tuberosity were acquired using a
3.0 T MRI scanner with a body matrix coil and a spine
coil (MAGNETOM Verio; Siemens AG, Germany), as
described previously [23]. The multi-slice sequencewith a slice thickness of 4 mm was conducted with thefollowing acquisition parameters: repetition time (TR),2820 ms; echo time (TE), 16 ms; field of view, 320 × 240
mm; flip angle, 129°; and voxel size, 0.5 × 0.5 × 4.0 mm.
Two-point Dixon images were obtained using the following sequences [10]: slice thickness, 3 mm; TR, 4.33
ms; TE1, 1.31 ms; TE2, 2.54 ms; optimized field of view,
286.4 × 365 mm; and flip angle, 9°. Based on the water/
fat chemical shift difference and, consequently, on theirphase difference in signal intensity, water and fat images
were produced in- and opposed-phase sequences. IntraMAT was calculated using the following equation: intraMAT (%) = mean signal intensity of fat × 100/(meansignal intensity of fat + mean signal intensity of water).

The ROIs in the VM were registered using OsiriX MD(version 11.0; OsiriX, Switzerland). To obtain the MV,
the ROIs were traced on each imaging slice throughout the entire muscle length, and the muscle CSA (­cm2)
within the ROIs was measured. The volume ­(cm3) ineach slice was determined by multiplying the muscle
CSA by 4 mm of slice thickness, and the MV was calculated by summing the volume in all slices. In addition,
CSA was calculated in the slice corresponding to the US
image, as indicated by the surface marker. To calculate
the intraMAT, the ROIs were carefully traced within the
fascial borders. The ROIs for the VM were set in 10 consecutive slices at the US measurement site as the centre.
IntraMAT (%) was determined as the average value of 10
slices [10].
Statistical analyses

Before all statistical tests, we confirmed no outliers
greater than the mean ± 3 standard deviations (SDs).
The Kolmogorov–Smirnov test was conducted to assess
for normally distributed data for all variables. Two-way
analyses of variance (ANOVAs) with age and posture

Table 2 Comparisons of muscle thickness and echo intensity in the supine and sitting postures evaluated using ultrasoundSupineTukey test

Sitting

T-value

Diff.

95% CI

p-value

Effect size
Partial η2

Mean ± SD

Total sample
MT, cm3.30 ± 0.64

3.04 ± 0.57

3.35

0.24

0.10 to 0.39

< 0.001

0.04

EI, a.u.

68.0 ± 15.4

78.1 ± 13.9

−5.63

−10.91−14.72 to −7.10< 0.001

0.11

Paired t-test

Cohen’s dYoungMT, cm3.56 ± 0.53

3.35 ± 0.51

3.45

0.20

0.08 to 0.32

< 0.001

0.40

EI, a.u.

59.2 ± 11.7

67.7 ± 10.2

−5.47

−8.45

−11.57 to −5.34< 0.001

0.77

Older
MT, cm3.19 ± 0.66

2.90 ± 0.54

6.24

0.28

0.19 to 0.38

< 0.001

0.48

EI, a.u.

72.1 ± 15.3

83.0 ± 12.6

−8.64

−10.91−13.42 to −8.40< 0.001

0.78

In total sample, results of the Tukey test for post hoc comparison against posture factor following two-way ANOVA are presented. In the older and young subgroups,
results of paired t-test amongst MT and EI in the supine and sitting postures are presented

Taniguchi et al. Journal of Physiological Anthropology(2023) 42:14

as factors were performed for MT and EI, and thenthe Tukey test for post hoc comparisons amongst postures was conducted. As the older and young subgroup
analysis, the values of MT and EI in the supine and sitting postures were compared using paired t-tests. We

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used Pearson’s coefficients to quantify the correlation
strengths amongst both (a) MT, MV, and CSA and (b)intraMAT and EI for the two measurement postures.
The difference in the correlation coefficients between thetwo measurement postures was examined using Meng’s

Fig. 3 Scatter plot for correlation analysis. A Scatter plot of cross-sectional area and muscle thickness (MT) measured in (i) supine and (ii) sitting
postures. B Scatter plot of muscle volume and MT measured in (i) supine and (ii) sitting postures. C Scatter plot of intramuscular adipose tissue
and echo intensity measured in (i) supine and (ii) sitting postures. A p-value < 0.05 (within each scatter plot) on the Pearson correlation coefficientindicates a significant difference between parameters measured by magnetic resonance imaging and ultrasound. Each plot means older men (□),
older women (◆), young men (〇), and young women (▲)

Taniguchi et al. Journal of Physiological Anthropology(2023) 42:14

test [24]. For secondary analyses, these tests were conducted separately for the older and young subgroups.
Furthermore, as complementary analyses, we used
Spearman’s correlation coefficients to test the correlation between the change ratios in MT and EI due to themeasurement posture change in each older and young
subgroup. Statistical analyses were performed using theStatistical Package for the Social Sciences (version 25.0,
IBM Japan Inc., Armonk, NY, USA). Statistical significance was set at p < 0.05.

Results
A summary of the muscle properties measured using
MRI is shown in Table 1. Amongst all participants, theCSA, MV, and intraMAT measured using MRIs were15.1 ± 4.5 ­cm2, 301.2 ± 98.5 c­ m3, and 6.5 ± 2.1%, respectively. Result of the two-way ANOVA for MT showed nosignificant interaction (F = 0.26, p = 0.613) but showed asignificant main effect in both age and posture (age: F =30.77, p < 0.001; posture: F = 10.60, p = 0.001). Similarly,
the results for EI showed no significant interaction (F =0.51, p = 0.474) but showed a significant main effect inboth age and posture (age: F = 68.02, p < 0.001; posture: F= 31.85, p < 0.001). The results of the Tukey test showed
MT when sitting was thinner than when supine, whereas
EI was higher when setting than when supine (Table 2
Total sample). In addition, the results of each young andolder subgroup on MT and EI were also similar to thoseof total sample (Table 2 Young and older).
Figure 3 shows the correlations between MT and
CSA and MV and that between EI and intraMAT in thesupine and sitting postures. Although significant correlations between MT and CSA and MV were observed forboth the supine and sitting postures (Fig. 3a, b), Meng’s
test showed that the correlation coefficient in the sitting
posture was significantly higher than that in the supine
posture. In contrast, intraMAT and EI in the supine andsitting postures showed significant correlations (Fig. 3c),and there was no significant difference in the correlation
coefficient between the two measurement postures.
Table 3 shows the results of correlation analyses performed separately for the older and young subgroups. In
both older and young participants, the correlation coefficients of MT and CSA and MV measured in the sitting
posture were significantly higher than those in the supine
posture. In young participants, the correlation coefficient
between intraMAT and EI in the sitting posture was significantly higher than that in the supine posture (Supplemental Fig. 1a). In contrast, no significant difference
was observed between the correlation coefficients in theolder patients (Supplemental Fig. 1b). Furthermore, a significant negative correlation between the change ratios
in MT and EI due to posture change was confirmed inPage 6 of 9

Table 3 Results of correlation coefficients and Meng’s test in theolder and young subgroups
SupineSittingMeng’s test

r-valuer-valuep-value

Between CSA and MT
Older

0.59

0.68

< 0.001

Young

0.69

0.75

0.010

Older

0.59

0.72

< 0.001

Young

0.71

0.86

< 0.001

Between MV and MT

Between intraMAT and EI
Older

0.51

0.49

0.557

Young

0.35

0.47

0.002

The r-value indicates the correlation coefficient between MT and EI measured in
the supine and sitting postures and CSA, MV, and intraMAT. The bold on r-values
shows the statistical significance of the correlation coefficients. A p-value < 0.05
on Meng’s test indicates a significant difference between correlation coefficientsamongst two measurement postures

young participants (ρ = −0.43, p = 0.004), but not in
older participants (ρ = −0.18, p = 0.089; Fig. 4).

Discussion
The correlation coefficients between (a) MT and (b)CSA and MV were significantly higher when sitting thanwhen supine, implying that MT measurements reflect
VM muscle quantity more accurately when sitting. EI
correlated significantly with intraMAT, and in young
individuals, the correlation coefficient was significantly
higher when sitting than when supine. The present study
was the first to investigate posture effects on MT and EI
measurements, and based on significantly stronger correlation coefficients, we recommend capturing US imagesof the VM in the sitting posture.
Giles et al. [25] reported that supine correlations of
CSA and MV with MT were 0.73 and 0.65, respectively,
in agreement with this study’s values of 0.65 (Fig. 3).
Consistent with our hypothesis, MT-CSA and MT-MV
correlations were significantly stronger when sitting thanwhen supine. These results were also consistent in theolder and young subgroups, and image acquisition in thesitting posture was superior to that in the supine posturefor evaluating muscle quantity.
Posture change from the supine to sitting causes a
decrease in the contact pressure between the posterior surfaces of the thigh and chair and an increase ingravity on the anterior thigh. These lead to changes inmuscle shape, which is associated with a consequent
decrease in MT when measured in sitting posture.
During supine VM measurements, soft tissue, including muscle and subcutaneous fat, is compressed, andit can be difficult to adjust the probe to the maximum

Taniguchi et al. Journal of Physiological Anthropology(2023) 42:14

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Fig. 4 Scatter plot of the change ratios in MT and EI accompanied by the measurement postures. A Scatter plot for older. B Scatter plot for young.
The vertical axis represents the change ratios in EI, and positive values mean that the EI is higher when sitting than when supine. The horizontal axis
represents MT change ratios, and positive values mean that the MT is thicker when sitting than when supine. Each plot means older men (□), older
women (◆), young men (〇), and young women (▲)

MT site because the MT site is not necessarily related
to the observable femur location (Fig. 1[i]). In contrast,
during sitting VM measurements, the MT location is
directly in line with the femur apex, making it generally easier to identify the appropriate VM measurement site. Since easier site identification is expected toyield more consistent measurements, we hypothesizedthat sitting measurements would yield stronger correlations with MRI-based muscle quantity indices, and our
results support this hypothesis. Although our results
also showed smaller MT values in sitting vs. supine postures (Table 2), this is irrelevant to the ultimate goal ofindicating muscle quantity; the indicator that has the

maximum correlation with the target quantity should be
preferentially used.
Experimental control of knee angle during measurement may be more important when sitting than whensupine because presumably the natural range of sitting
knee angles is larger than the natural range of supine knee
angles. Generally, the muscle fascicle length increases
along with the joint angle, resulting in a decrease of MTby the muscle stretched [26, 27]. That is, if one assumes
that MT is directly affected by knee angle — because
knee angle stretches and thus deforms the muscle —then knee angle control is necessary to achieve reliablemeasurements.

Taniguchi et al. Journal of Physiological Anthropology(2023) 42:14

This study found no difference between the two measurement postures for the correlation between EI and
intraMAT in all participants. A previous study [21]reported no difference in EI within the entire muscle
length. In other words, muscle composition is unaffected by muscle morphology, stretching, and/or posture. However, our results indicated that the EI value inthe sitting posture was higher than that in the supine
posture (supine, 68.0 ± 15.4 a.u.; sitting, 78.1 ± 13.9
a.u. [Table 2]). In addition, the effect size of EI change
between two measurement postures was relatively larger
than that of MT change. This can be explained by theattenuation of the US beam according to depth; because
the MT in the sitting posture was significantly thinner,
depth-dependent attenuation of the US beam was likely
reduced. In the young subgroup, the correlation coefficient between EI and intraMAT was higher in the sitting posture than in the supine posture (supine, r = 0.35;
sitting, r = 0.47 [Table 3 and Supplemental Fig. 1a]). The
VM in the young subgroup was thicker and influenced
by greater US attenuation, especially in the supine posture. In contrast, thinning of MT in the sitting posture
mitigates the attenuation effect. In fact, a decrease in MT
due to postural changes from supine to sitting in young
individuals was significantly associated with an increase
in EI (refer to Fig. 4). Therefore, the correlation between
EI and intraMAT became stronger in young individuals.
These results suggest that the acquisition of US imaging
in the sitting posture is more appropriate when sitting
than when supine for MT and EI measurement in young
individuals.
There were several limitations to the present
study. First, only two postures, i.e. supine and sitting, were compared. VM measurements in the sitting posture included both effects of the pressure
on the posterior distal thigh and muscle stretch of
the VM due to knee flexion. Although the present
study determined the effect of the pressure on theposterior distal thigh, the effect of muscle stretch
on MT and EI measurements was not clear. Second,
we could not exclude the presence of osteoarthritis(OA) because no radiographs were taken. Since OA
is a common disease in the elderly, the participantsin this study might have OA in one or more joints.
Especially, decreased MT and enhanced EI are associated with functional disabilities and worse symptoms in patients with knee OA [28–30]. However,
it is unclear whether sitting VM measurements are
sufficient for detecting muscle degeneration of knee
OA. Future studies are required to verify the efficacy of VM measurements in the sitting posture forknee OA patients.

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Conclusions
The results of this study indicated that MT was moreclosely associated with muscle quantity when sitting
than when supine. Correlations between EI and intraMAT were significantly higher when sitting than whensupine, especially in young individuals. These findings
suggest that assessment of VM muscle quantity in thesitting posture is superior for young and older individuals, and assessment of VM muscle quality in the sitting
posture is most effective for younger individuals withgreater muscle quantity.
Abbreviations
CSA	Cross-sectional area
EI	Echo intensity
IntraMAT	Intramuscular adipose tissue
ICC	Intraclass correlation coefficient
MRI	Magnetic resonance imaging
MT	Muscle thickness
MV	Muscle volume
OA	Osteoarthritis
ROI	Region of interest
TE	Echo timeTR	Repetition timeUS	Ultrasound
VM	Vastus medialis

Supplementary Information
The online version contains supplementary material available at https://​doi.​
org/​10.​1186/​s40101-​023-​00331-6.
Additional file 1: Supplemental Fig. 1. a Scatter plot for correlation
analysis inyoung individuals. b Scatter plot for correlation analysis in older
individuals.
Acknowledgements
The authors thank all individuals who participated in the study. We would liketo thank Dr. Pataky T. C. (Kyoto University) and Editage (www.​edita​ge.​jp) for
English language editing.
Authors’ contributions
All authors conceived the study, participated in its design, coordination, andacquisition of data. MT, YF, MY, TH, MY, and RN were involved in recruiting
participants and collection of data. MT, YF, MY, and NI participated in interpretation of the results and editing the whole manuscript. All authors contributed
significantly and read and approved the final manuscript.
Funding
This study was supported by the JSPS KAKENHI Grant-in-Aid for Scientific
Research (20K19376). The grant was used for data collection, data analysis, andwriting the manuscript in this study.
Availability of data and materials
The datasets used and/or analysed during the current study are available fromthe corresponding author on reasonable request.

Declarations
Ethics approval and consent to participate
All study procedures were approved by the Ethics Committee of the Kyoto
University Graduate School of Medicine (R1746). All participants provided
written informed consent.

Taniguchi et al. Journal of Physiological Anthropology(2023) 42:14

Consent for publication
All participants signed the consent for publication.
Competing interests
The authors declare that they have no competing interests.
Author details
1
Human Health Sciences, Graduate School of Medicine, Kyoto University,
Kyoto 606‑8507, Japan. 2 Faculty of Rehabilitation, Kansai Medical University,
Hirakata 573‑1136, Japan. 3 School of Health and Sport Science, Chukyo
University, Aichi 470‑0393, Japan. 4 Japan Society for the Promotion of Science, Tokyo 102‑0083, Japan. 5 Kyoto University Institute for the Futureof Human Society, Kyoto 606‑8507, Japan. 6 National Institute of Healthand Nutrition, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo 162‑8636, Japan. 7 Institute for Active Health, Kyoto Universityof Advanced Science, Kyoto 621‑8555, Japan.
Received: 3 March 2023 Accepted: 9 July 2023

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