The Relations Between NIRS-Based Estimates of Mitochondrial Capacity and Knee Joint Muscle Function in Physically Active Women and Men
- Gosalia, Jigar
- [University Park, Pennsylvania] : Pennsylvania State University, 2020.
- Physical Description:
- 1 electronic document
- Additional Creators:
- Proctor, David Nathan
- Restrictions on Access:
- Open Access.
- Background and Purpose: Near infrared spectroscopy (NIRS) is a non-invasive method that is commonly used to assess muscle mitochondrial oxidative capacity through the use of brief arterial cuff occlusions after muscle activation (electrically stimulated). Emerging evidence suggests that higher values of NIRS derived recovery rate constant (k), a measurement of mitochondrial oxidative capacity, is associated with greater muscle endurance. However, the relation between NIRS mitochondrial capacity and conventional clinical measures of muscle function have not been established. Accordingly, the primary purpose of this study was to determine the associations between NIRS mitochondrial capacity and knee joint isokinetic endurance and strength, and whether these associations differ in physically active women vs. men Methods: Fifteen young (8 men, 7 women; 23 ± 3 yr) moderate-to-highly active adults completed the NIRS mitochondrial capacity protocol, consisting of multiple (n=4) measurements of k for the vastus lateralis and medial hamstrings involving a series of brief arterial occlusions following neuromuscular electrical stimulation. Assessment of muscle function included muscle endurance measured as isokinetic total work, and muscle strength measured as peak moment normalized to body mass. Pearson correlations were used to analyze associations between NIRS mitochondrial capacity and isokinetic muscle endurance, and strength. Linear regression models were fitted to determine the best predicted response of isokinetic muscle endurance, and strength. Sex differences were analyzed using independent t-tests. Results: There was a positive association between NIRS mitochondrial capacity in the vastus lateralis and knee extensor total work normalized to body mass in women (r = 0.718, p = 0.004). In the overall sample, there was a positive association between mitochondrial capacity in the vastus lateralis and knee extensor normalized peak moment (r = 0.471, p = 0.009) and a positive association between mitochondrial capacity in the medial hamstrings and knee flexor normalized peak moment (r = 0.370, p = 0.048). Additionally, an overall regression analysis revealed that NIRS-derived mitochondrial capacity and physical activity levels best predicted both isokinetic muscle endurance and strength in both muscles. Lastly, absolute and relative measures of muscle function were higher in men compared with women (p<0.05). Conclusion: NIRS-based estimates of mitochondrial capacity are positively associated with isokinetic endurance and strength in the knee joint musculature of physically active young adults. Future studies should investigate these associations in activity-matched women and men, possible deficits in muscle function due to knee joint injury, and the mechanisms underlying any observed differences.
- Dissertation Note:
- M.S. Pennsylvania State University 2020.
- Technical Details:
- The full text of the dissertation is available as an Adobe Acrobat .pdf file ; Adobe Acrobat Reader required to view the file.
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