An 8-Week Resistance Training Protocol Is Effective In Adapting Quadriceps But Not Patellar Tendon Shear Modulus Measured By Supersonic Shearwave Imaging

Abstract

Habitual loading and resistance training (RT) can determine changes in muscle and tendon morphology but also in its mechanical properties. Conventional ultrasound (US) evaluation of these mechanical properties present limitations that can now be overcome with the advent of Supersonic Shearwave Imaging (SSI). The objective of this study was to analyze the Vastus Lateralis (VL) and patellar tendon (PT) mechanical properties adaptations to an 8-week RT protocol using SSI. We submitted 15 untrained health young men to an 8-week RT directed knee extensor mechanism. VL and PT shear modulus () was assessed pre and post intervention with SSI. VL muscle thickness (VL MT) and knee extension torque (KT) was also measure pre and post intervention to ensure the RT efficiency. Significant increases were observed in VL MT and KT (pre= 2.40 {+/-} 0.40 cm and post= 2.63 {+/-} 0.35 cm, p = 0.0111, and pre= 294.66 {+/-} 73.98 Nm and post= 338.93 {+/-} 76.39 Nm, p = 0.005, respectively). The 8-week RT was also effective in promoting VL adaptations (pre= 4.87 {+/-} 1.38 kPa and post= 9.08.12 {+/-} 1.86 kPa, p = 0.0105), but not in significantly affecting PT (pre= 78.85 {+/-} 7.37 kPa and post= 66.41 {+/-} 7.25 kPa, p = 0.1287). The present study showed that an 8-week resistance training protocol was effective in adapting VL but not PT . Further investigation should be conducted with special attention to longer interventions, to possible PT differential individual responsiviness and to the muscle-tendon resting state tension environment.