Methods: The NIRS interface (interoptode distance 20 mm) enables dual-channel monitoring at 10 Hz during PFM sustained maximal voluntary contraction (SMVC) with a 4-wavelength (766nm, 861nm, 906nm 971nm) continuous wave instrument. Changes in oxy and deoxy-hemoglobin concentration (O2Hb/HHb) in the right and left PFM were used to derive HbDiff (O2Hb - HHb). Established HbDiff half-recovery time (½RT) methodology was then applied to quantify PFM reoxygenation commencing on cessation of SMVC.
Results: SMVCs were monitored successfully in 15 asymptomatic women; contraction strength and duration varied; post- SMVC reoxygenation HbDiff (½RT) was quantified for both the right and left sides of the PFM.
Conclusions: Skeletal muscle recovery from exercise-induced oxygen deficit indicates oxidative capacity; this equates with muscular fitness. SMVC is a robust measure of muscle strength and endurance, and HbDiff in occlusion free ½RT analysis reflects metabolic changes within muscle better than O2Hb. This pilot study shows the feasibility of using transvaginal NIRS data to derive a quantitative measure of PFM oxygen kinetics relevant to improving the evaluation PFM dysfunction in UUI and the efficacy in PMFT.