Near-infrared spectroscopy of superficial and deep rectus femoris reveals markedly different exercise response to superficial vastus lateralis

13 healthy men, mean age 21 ± 2 years, Japan-based.

Cycle exercise transitions from unloaded to heavy work rates with simultaneous time-resolved near-infrared spectroscopy (NIRS) sampling of deep (RF-d) and superficial (RF-s, VL-s) quadriceps muscles.

Comparison between muscle sites (superficial vastus lateralis [VL-s] vs. superficial rectus femoris [RF-s] vs. deep rectus femoris [RF-d]) and between exercise onset and offset.

Muscle deoxygenation kinetics (mean response time [MRT] of deoxy[Hb+Mb]) and amplitude following exercise onset and offset.surrogate