Figure 1. Representative Magnetic Resonance Imaging (MRI) scans from one subject.

A: Cross-sectional MRI of the mid thigh with quadriceps muscles outlined and annotated. B. Thresholded cross-sectional MRI of mid-thigh. Dark areas were used for quadriceps CSA quantification to eliminate non-muscle tissue such as intermuscular adipose tissue. C: Longitudinal MRI showing patellar tendon moment arm (dPT) as the perpendicular distance between the patellar tendon and the tibio-femoral contact point. D: cross-sectional view of mid thigh muscle fiber tractography from DSI studio. VL: vastus lateralis, VI: vastus intermedius, RF: Rectus Femoris, VM: vastus medialis, SA: Sartorius, AL: Adductor Longus, AM: Adductor Magnus, BF: Biceps Femoris, ST: Semitendinosus, SM: Semimembranosus.