Flexible strain sensors have great potential in wearable applications, yet it is challenging to achieve the desired sensitivity, stretchability, reversibility, durability, and skin conformity. This work reports a kirigami- structured strain sensor in the shape of an anklet, which was modified with gold decorated multi-walled carbon nanotubes and passivated with ecoflex. The proposed sensor depicted an ultra-high stretchability for an applied strain up to 180%. The extremely high sensitivity and the Internet-of- Things interface enable the real-time monitoring of ankle strain of injured patients undergoing rehabilitation.