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Development and Application of a Novel Accelerometry-based Index of Performance Fatigability in Older Adults

Qiao, Yujia (Susanna) (2023) Development and Application of a Novel Accelerometry-based Index of Performance Fatigability in Older Adults. Doctoral Dissertation, University of Pittsburgh. (Unpublished)

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Performance fatigability, defined as performance deterioration during a standardized physical task, is disabling and multifactorial and has been identified as an early indicator of aging and a prevalent energy disorder among older adults. Developing an objective, sensitive, and valid accelerometry-based performance fatigability measure helps us better quantify the prevalence and understand the underlying biological mechanisms of performance fatigability. Here, I aimed to 1) develop a novel accelerometry-based performance fatigability index and characterize severity and sex difference of fatigability; 2) validate our fatigability index in an external large cohort; and 3) evaluate the associations between skeletal muscle energetics and our fatigability index. In Aim 1, I developed the Pittsburgh Performance Fatigability Index (PPFI) to quantify walking-based performance fatigability using wrist-worn accelerometry in the Developmental Epidemiological Cohort Study. Conceptually, PPFI quantifies the percentage of performance decrement during a walking task by comparing area under the observed cadence-versus-time trajectory to a hypothetical area that would be observed in the absence of fatigue. PPFI scores from a fast-paced 400m walk were higher and more variable than from a usual-paced 400m walk and revealed sex differences. In Aim 2, I correlated PPFI against physical function, leg peak power, cardiorespiratory fitness and perceived fatigability in the Study of Muscle, Mobility and Aging (SOMMA), which underscored the good construct validity of PPFI. Furthermore, I used decision tree methodology to identify sex-specific PPFI cut-points that optimally discriminated 400m gait speed. In Aim 3, using SOMMA, I found lower Complex I&II-supported oxidative phosphorylation, lower Complex I&II-supported electron transfer system and maximal adenosine triphosphate production were significantly associated with higher PPFI scores and higher odds of being in a more severe PPFI severity stratum.
The successful completion of these aims provided us an objective, sensitive, and valid accelerometer-based performance fatigability index to better capture performance fatigability during walking tasks. Our understanding of muscle energetics and performance fatigability also opened new horizons for future lifestyle interventions and pharmaceutical trials aimed at reducing fatigability and improving functional performance. Collectively, this dissertation aids early detection and better management of performance fatigability thus will alleviate public health burden of mobility disability among older adults.


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Item Type: University of Pittsburgh ETD
Status: Unpublished
CreatorsEmailPitt UsernameORCID
Qiao, Yujia (Susanna)susannaqiao@pitt.eduYUQ140000-0001-7356-3320
ETD Committee:
TitleMemberEmail AddressPitt UsernameORCID
Committee ChairGlynn, Nancy
Committee MemberHawkins, MarquisMAH400@pitt.eduMAH400
Committee MemberHarezlak,
Committee MemberSantanasto, Adam J.AJS51@pitt.eduAJS51
Committee MemberPamela, Totopet3@pitt.edupet3
Date: 9 May 2023
Date Type: Publication
Defense Date: 4 April 2023
Approval Date: 9 May 2023
Submission Date: 27 April 2023
Access Restriction: 2 year -- Restrict access to University of Pittsburgh for a period of 2 years.
Number of Pages: 160
Institution: University of Pittsburgh
Schools and Programs: School of Public Health > Epidemiology
Degree: PhD - Doctor of Philosophy
Thesis Type: Doctoral Dissertation
Refereed: Yes
Uncontrolled Keywords: Fatigue, mobility, skeletal muscle energetics
Date Deposited: 10 May 2023 02:08
Last Modified: 10 May 2023 02:08


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