Time course of changes in passive properties and joint position sense after static stretching.

Purpose: Static stretching (SS) improves flexibility but may impair the accuracy of joint position sense. Therefore, this study aimed to investigate the acute effects and time course of SS on the accuracy of joint position sense, range of motion (ROM), and muscle–tendon unit (MTU) stiffness. Methods: This study randomly assigned 16 healthy, young males to the SS and control conditions. SS intervention in the SS condition was performed on the plantar flexors of the dominant leg for three sets of 60 s. The participants were instructed to sit for 240 s in the control condition. The ankle dorsiflexion (DF) ROM, passive torque at DF ROM, MTU stiffness, and joint position sense on the dominant leg side were measured before (PRE) and immediately (POST) and at 5, 10, and 20 min postintervention. Results: A significant interaction effect was observed in the relative error in the joint position sense, and significant increases were noted in POST compared to PRE in the SS condition. Further, significant interactions were observed in DF ROM, passive torque at DF ROM, and MTU stiffness. The SS condition demonstrated significant increases in DF ROM and passive torque at DF ROM compared to PRE with POST, 5 min, and 10 min, and MTU stiffness significantly decreased in POST compared with PRE. Conclusion: Our results indicated that the accuracy of the joint position sense decreased immediately after SS, but returned to baseline in a very short time. [ABSTRACT FROM AUTHOR]