@article{oai:kanazawa-u.repo.nii.ac.jp:00048783,
 author = {北川, 孝 and 三秋, 泰一 and 大角, 久美子 and 松井, 伸公 and 寺田, 茂 and Kitagawa, Takashi and Miaki, Hiroichi and Osumi, Kumiko and Matsui, Nobumasa and Terada, Shigeru},
 issue = {1},
 journal = {Journal of wellness and health care, Journal of wellness and health care},
 month = {Aug},
 note = {Muscle echo intensity (EI) determined by ultrasonography has recently been reported as
an index of intramuscular fat. The muscle thickness (MT) and EI of the quadriceps femoris
muscle were reported to be influenced by the muscle strength (MS) of the knee extensors.
This study was performed to investigate whether the MT and EI of the quadriceps femoris
are associated with the MS of knee extensors, and to establish a predictive formula for the
maximal isometric MS of knee extensors.
Forty healthy volunteers 20-59 years old were included in this study. The maximal
isometric MS of knee extensors on the dominant extremity was measured at knee
flexion of 60°, and was defined as the maximal value over three repeated measurements.
Transverse ultrasound images of the quadriceps on the dominant extremity were obtained
with a B-mode ultrasound imaging device and multi-frequency linear transducer. During
measurements, the participants were completely relaxed and sat comfortably with
the knee flexed at 90°. A 10-MHz transducer with gain of 58 dB was used during all
measurements. The transducer was positioned perpendicular to the longitudinal axis of
the quadriceps femoris, at the midpoint between the anterior superior iliac spine and
the proximal end of the patella. The same investigator then obtained three consecutive
images. The subcutaneous fat thickness, MT of each muscle, and EI of each muscle were
analyzed from three images acquired for the rectus femoris (RF) and vastus intermedius
(VI), and the mean values of the three measurements were recorded. Pearson’s and
Spearman’s correlation coefficients were calculated to investigate the relationships between
subcutaneous fat thickness, MT, EI, physical characteristics, and MS. Stepwise multiple
regression analysis was then performed with MS value as the dependent variable, and the
characteristics of the participants and values from the ultrasound images as independent
variables. In addition, multiple regression analysis was performed in two groups divided
according to age, i.e., the young adult group and the middle-aged group.
There were no significant differences in height, weight, BMI, or muscle circumference
between the young adult group and middle-aged group. MS showed significant negative
correlations with subcutaneous fat thickness, RFEI, and VIEI, and significant positive
correlations with height, weight, circumference, RFMT, and VIMT. Stepwise regression
analysis identified height and VIMT as factors significantly associated with MS (adjusted
R2 = 0.65). Height and VIMT contributed to MS in young and middle-aged individuals.},
 pages = {47--53},
 title = {Prediction of maximum isometric muscle strength of knee extensors using ultrasonography},
 volume = {43},
 year = {2019}
}