Muscle performance in octogenarians: Factors affecting dynapenia.

BACKGROUND: The muscle performance is associated with several health outcomes in adults, however modifiable and non-modifiable risk factors in octogenarians have not yet been fully investigated. The aim of this study was to analyze the potential risk factors that negatively affect muscle strength in octogenarians. METHODS: This observational, descriptive, cross-sectional study included 87 older adult participants (56 women and 31 men) attending a geriatric clinic. General anthropometrics, health history, and body composition data were collected. Muscle strength was assessed by handgrip strength (HGS), appendicular skeletal muscle mass (ASMM) and the percentage of body fat were identified by Dual Energy X-ray Absorptiometry, and muscle quality index (MQI) was defined as the ratio of HGS by upper limbs ASMM. Multiple linear regression was conducted to determine predictive factors of the muscle strength. RESULTS: Females had lower HGS (1.39 kg) than male participants (p = 0.034). An increase of one unit MQI was associated with an increase of 3.38 kg in the HGS (p = 0.001). Each additional year of age was associated with a decrease of 0.12 kg in the HGS (p = 0.047). Regarding ASMM, an increase of one unit was associated with an increase of 0.98 kg in the HGS (p = 0.001). There was no association between dynapenia, body fat percentage, diseases and polypharmacy (p > 0.05). CONCLUSION: The gender, age, MQI, and ASMM influenced muscle strength of octogenarians. These intrinsic and extrinsic factors are relevant to improve our understanding of age-related complications and outline treatment guidance by healthcare professionals.

Field-Based Estimates of Muscle Quality Index Determine Timed-Up-and-Go Test Performance in Obese Older Women.

Objective: The muscle quality index (MQI) is associated with numerous health outcomes in adults; however, the effects of distinct MQI on functional capacity in obese older women have not yet been fully investigated. Thus, we investigated the contribution of different muscle quality indices on TUG performance prediction in obese older women. We secondarily evaluated the association between MQI, aerobic capacity performance (Treadmill performance and 6-minute walk test), and obesity indices (BMI, body fat percentage, and neck, waist, and hip circumference). Methods: Participants included 64 obese older women (mean age 67.05 ± 5.46 years, body fat ≥ 35%). General anthropometric, health history, body composition, treadmill exercise, and functional test (Time up and go) measures were collected. A hydraulic dynamometer was used to assess muscle strength, and Dual Energy X-ray Absorptiometry (DXA) to identify body fat percentage. The field MQI was defined as the highest reading divided by the subject's body mass index (BMI), while the laboratory MQI was obtained by the ratio of grip strength to the entire arm muscle in kilograms measured by DXA. A hierarchical multiple regression was performed to predict TUG-test performance. Results: An increase in field MQI of one unit is associated with a decrease of 2.59 seconds in the TUG test (ß = -0.540; p = 0.004). There was no association between laboratory MQI and TUG performance (ß = 0.067; p = 0.712). Furthermore, field MQI displays a positive correlation (p < 0.05) with aerobic capacity performance (6-minute walk test and peak O2 consumption) and a negative correlation (p < 0.05) with diverse obesity indices (neck and waist circumference, body fat, and BMI). Conclusion: MQI displayed an important prediction with TUG-test, a positive correlation with aerobic capacity, and a negative correlation with obesity indices.