A Novel NIRS Protocol For Within- and Between-Limb Comparison of Lower Limb Muscle Mitochondrial Capacity
- Hanna, Rewais
- [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 can be used to estimate skeletal muscle mitochondrial capacity via surface electrical stimulation and a series of brief ischemic cuff occlusions. NIRS-based mitochondrial capacity, determined by the rate of recovery (k) of muscle oxygen consumption post stimulation, allows for the discrimination between high fit and low fit (e.g., patient populations) individuals. The purpose of the present study was to develop and assess the reproducibility of a novel bilateral NIRS protocol enabling within and between-limb comparisons of muscle mitochondrial capacity. Methods: Sixteen young (8 women, 8 men; 22+3 yr) moderate-to-highly active adults underwent a bilateral electrical stimulation protocol in which multiple (n=4) measurements of k for both VL muscles (supine position) followed by both MH muscles (prone position) were determined during a single test session. Each subject repeated the protocol on a separate day. Within-session repeatability of bilateral NIRS k values for both muscles was assessed, as was the reliability and bias of the mean k values between days and between limbs. Comparison of mean values between-sessions and between-limbs were analyzed using paired t-tests. Results: The mean value of k across the two sessions was 1.58+0.31 min-1 and 1.68+0.29 min-1 in the VL (n=59 replicates) and the MH (n=54 replicates), respectively, with no systematic differences in k between sessions for either muscle in either limb (all p>0.095). Moderate-to-high within-day reliability of NIRS k measurements was observed for the VL (CV =13.2+5.8%; ICC = 0.88) and the MH (14.7+6.5%; ICC = 0.86) muscles of both limbs. Intra-rater reliability of NIRS recovery curve fitting was quite high (CV%=4.6±2.5 ICC=0.98 for VL; CV%=4.2±3.3% ICC=0.97 for MH). Conclusions: This bilateral, time efficient NIRS protocol appears to provide valid and reproducible measures of mitochondrial capacity in the knee joint muscles of young athletic women and men. These findings support the use of this protocol in future studies to assess limb- and muscle-specific changes in mitochondrial capacity in response to interventions. This method could be particularly useful for assessing limb- and muscle-specific changes in ACL-reconstructed patients.
- 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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