Vastus lateralis exhibits non-homogenous adaptation to resistance training

Introduction: Variations in transverse point of measure on the vastus lateralis (VL) may significantly affect the relationship between structure and function. The purpose of this study was to compare changes in muscle architecture at 2 commonly used points of measure (VL0 and VL5). Methods: Maximal strength (1-repetition maximum [1RM] barbell squat) and muscle architecture were assessed PRE and POST 15 weeks of periodized resistance training. VL0 was 50% of the straight line distance between the greater trochanter and lateral epicondyle of the femur. VL5 was 5cm medial to VL0. Results: Increases in 1RM strength (3.7±2.4 kg; P=0.004) were observed. Changes in muscle thickness (MT) at VL5 were significantly greater than at VL0 (P=0.006). Changes in strength correlated with changes in muscle architecture at VL0 only (MT: r=0.561; fascicle length: r=0.503). Conclusions: Changes in muscle architecture appear to occur in a non-homogeneous manner.