Correlation coefficients for trunk muscle between by KinCom and PTMI in study 1.

<p>Correlation coefficients for trunk muscle between by KinCom and PTMI in study 1.</p

Scatter plot of flexion and extension torque by KinCom and the PTMI instrument.

<p>The flexion torque (A) and extension torque (B) were recorded using each instrument.</p

Prevalence of trunk sarcopenia.

<p>Values below the lower limit of reference intervals from young and healthy adults were defined as trunk sarcopenia. Subjects were divided into five groups: 40–49 (from 40 to 49 years of age), 50–59 (from 50 to 59 years of age), 60–69 (from 60 to 69 years of age), 70–79 (from 70 to 79 years of age), and 80+ (80 years of age and over).</p

Age-related change in trunk flexion torque (A), extension torque (B), and flexion/extension ratio (C).

<p>The percentage of flexion and extension torque against the reference values for young and healthy adults are shown. Subjects were divided into four groups: <50 (under 50 years of age), 50–59 (from 50 to 59 years of age), 60–69 (from 60 to 69 years of age), and 70+ (above 70 years of age) in males and females.</p

Demographic data for participants in study 2.

<p>Demographic data for participants in study 2.</p

Portable trunk muscle strength measurement instrument.

<p>Overall appearance of the portable trunk muscle strength measurement instrument (A). The position on KinCom (B, C) and the portable trunk muscle strength measurement instrument (D, E).</p

Mean value of trunk muscle strength of healthy young adults and the estimated reference interval.

<p>Mean value of trunk muscle strength of healthy young adults and the estimated reference interval.</p