A quantitative evaluation of kinetic parameters, the joint’s range of motion, heart rate, and breathing rate, can be employed in sports performance tracking and rehabilitation monitoring following injuries or surgical operations. However, many of the current detection systems are expensive and designed for clinical use, requiring the presence of a physician and medical staff to assist users in the device’s positioning and measurements. The goal of wearable sensors is to overcome the limitations of current devices, enabling the acquisition of a user’s vital signs directly from the body in an accurate and non–invasive way. In sports activities, wearable sensors allow athletes to monitor performance and body movements objectively, going beyond the coach’s subjective evaluation limits. The main goal of this review paper is to provide a comprehensive overview of wearable technologies and sensing systems to detect and monitor the physiological parameters of patients during post–operative rehabilitation and athletes’ training, and to present evidence that supports the efficacy of this technology for healthcare applications. First, a classification of the human physiological parameters acquired from the human body by sensors attached to sensitive skin locations or worn as a part of garments is introduced, carrying important feedback on the user’s health status. Then, a detailed description of the electromechanical transduction mechanisms allows a comparison of the technologies used in wearable applications to monitor sports and rehabilitation activities. This paves the way for an analysis of wearable technologies, providing a comprehensive comparison of the current state of the art of available sensors and systems. Comparative and statistical analyses are provided to point out useful insights for defining the best technologies and solutions for monitoring body movements. Lastly, the presented review is compared with similar ones reported in the literature to highlight its strengths and novelties.

Piezoelectric energy harvesters are promising transducers for supplying low power mobile/portable electronics, wearable and implantable devices, or for autonomous wireless sensors and microsystems, which are of increasing importance for monitoring environmental and structural health, sensing in automotive applications, human health and wellness. One of the main requirements for such applications is the ability to develop piezoelectric materials and devices generating enough voltage/power even from tiny mechanical or biomechanical excitations at extremely low frequencies and out-of-resonance. In addition to high performance, wearable devices and medical implants require biocompatibility of materials/devices in the long term. This work reviews recent advances on biocompatible, flexible and compliant energy harvesters based on piezoelectric thin films scavenging energy from (bio)mechanical movements or flows induced deformations.