Relationship Between Respiratory Muscle Strength, Handgrip Strength, and Muscle Mass in Hospitalized Patients.

BACKGROUND: Minimal information is available to validate measurement of respiratory muscle strength (RMS) in the clinical setting. The purpose of this study was to determine the correlation between maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), and sniff nasal inspiratory pressure (SNIP) with handgrip strength (HGS) and cross sectional muscle area obtained via diagnostic abdominal computed tomography (CT). MATERIALS AND METHODS: Measures of MIP, MEP, SNIP, and HGS were obtained from individuals that participated in a previously published study; individuals who had an abdominal CT completed with (±)7 days of obtaining RMS measures were included. Both RMS and HGS were measured within 48-72 hours of admission; for RMS, the highest absolute (cm H2 O) and percent predicted values were recorded, and the average of 3 HGS measurements (kg) was documented. Cross-sectional muscle area (cm2 ) at the third lumbar region was recorded. Spearman's correlation coefficient was used to assess the relationship between variables. RESULTS: A total of 35 participants were included. HGS was correlated to absolute MIP (rs = 0.62, rs = 0.61), MEP (rs = 0.74, rs = 0.73), and SNIP (rs = 0.58, rs = 0.54) for males and females, respectively. Crosss-sectional muscle area was correlated with absolute MIP (rs = 0.66), MEP (rs = 0.58), and SNIP (rs = 0.783) for men and absolute SNIP (rs = 0.56) among women. CONCLUSION: Measures of RMS represent a promising assessment of muscle mass and function among hospitalized patients.

Dietary protein intake is not associated with 5-y change in mid-thigh muscle cross-sectional area by computed tomography in older adults: the Health, Aging, and Body Composition (Health ABC) Study.

BACKGROUND: A higher protein intake is suggested to preserve muscle mass during aging and may therefore reduce the risk of sarcopenia. OBJECTIVES: We explored whether the amount and type (animal or vegetable) of protein intake were associated with 5-y change in mid-thigh muscle cross-sectional area (CSA) in older adults (n = 1561). METHODS: Protein intake was assessed at year 2 by a Block food-frequency questionnaire in participants (aged 70-79 y) of the Health, Aging, and Body Composition (Health ABC) Study, a prospective cohort study. At year 1 and year 6 mid-thigh muscle CSA in square centimeters was measured by computed tomography. Multiple linear regression analysis was used to examine the association between energy-adjusted protein residuals in grams per day (total, animal, and vegetable protein) and muscle CSA at year 6, adjusted for muscle CSA at year 1 and potential confounders including prevalent health conditions, physical activity, and 5-y change in fat mass. RESULTS: Mean (95% CI) protein intake was 0.90 (0.88, 0.92) g · kg-1 · d-1 and mean (95% CI) 5-y change in muscle CSA was -9.8 (-10.6, -8.9) cm2. No association was observed between energy-adjusted total (ß = -0.00; 95% CI: -0.06, 0.06 cm2; P = 0.982), animal (ß = -0.00; 95% CI: -0.06, 0.05 cm2; P = 0.923), or plant (ß = +0.07; 95% CI: -0.06, 0.21 cm2; P = 0.276) protein intake and muscle CSA at year 6, adjusted for baseline mid-thigh muscle CSA and potential confounders. CONCLUSIONS: This study suggests that a higher total, animal, or vegetable protein intake is not associated with 5-y change in mid-thigh muscle CSA in older adults. This conclusion contradicts some, but not all, previous research. This trial was registered at www.trialregister.nl as NTR6930.

THE STRENGTH PER UNIT MUSCLE AREA IN THE GROWING GENERATION / 体力科学

Muscle strength per unit muscle area related to age was investigated in normal 131 males and 127 females, 7 to 18 years of age. A cybex machine was used to measure the isometric muscle strength of elbow flexion and extension, knee flexion and extension, respectively. The cross-sectional muscle area of extensor and flexor at right upper arm and thigh were determined by using ultrasonic apparatus. The muscle area in male increased with age from 7 years to 17 or 18 years. Females showed increment in muscle area from 7 to 12 years for elbow flexor muscle, and from 7 to 16 years for another muscles. Muscle strength in both males and females increased with age from 7 to 16 or 17 years. Muscle strength per unit muscle area tended to increase with age in males from 7 to 12 years, and in girls 7 to 9 years except for elbow extension. The strength per area under 12 years of age for males and 9 years of age for females except for elbow extension were significantly lower than that of the above age. There were little differences in the strength per unit area with age among males from 13 to 18 years and females from 10 to 18 years, respectively. These results indicate that under 12 years for boys and 9 years for girls the increment in muscle area with age is not accompanied with the development of muscle function.