## 1 _Editorial_ Special Issue on Performance Analysis in Sport and Exercise
GPS technology has provided specific insights into sub-elite youth football training load and recovery status to monitor training environments and load changes [2]. Inertial Measurement Sensors (IMUs) can measure the movements and orientation of an object in space, thanks to the availability of accelerometers, magnetometers, and gyroscopes. Using a system of IMUs, it was possible to effectively recognize the movements and evaluate the accuracy of the movement of a traditional Chinese sport (Baduanjin) [3]. IMUs have also been applied in the clinical domain; a study on ataxia-telangiectasia patients showed the application of wearable motion acquisition systems to assess motor skills through recursion, harmony, and symmetry measurements [4]. Even if GPS and IMU systems are small and easy devices, they must be worn by the athlete or subject to obtain measurements. In this context, these modern devices have been employed to produce mathematical models able to describe the characteristics of kayak stroke in terms of periodicity and average strength, and the effects of these on stroke frequency [5]. Similarly, in [6], traditional measurement procedures were exploited to define statistical prediction methods such as linear recommendation scores, logistic regression, discriminant analysis, and a neural network for identifying talents in tennis. Differently from these, the video-analysis measurements are the least invasive, as they do not involve devices directly attached to the athlete or subject; however, this allows one to assess the movement only by a video recording with high-speed cameras. Using this technology, it was possible to record ball trajectories to analyze the throwing behavior (biomechanics, speed) of high-level players and athletes and to understand the technical differences of different ages. Specifically, the study described in [7] investigated the situational dependence of concrete environmental conditions (\"constraints\") of successful throwing actions, and the biomechanics of throwing at the goal compared to the throwing speed of world-class water polo players under competition conditions. The study in [8], using a 3D video analysis, compared the biomechanical parameters of top Italian senior and youth shot put athletes with world-class athletes evaluated in previous investigations. Moreover, the semi-automatic InStat Fitness video system has made it possible to assess the running performance of footballers based on ball possession to determine its potential influence on the team's results in the UEFA Champions League [9], and to classify performance according to the specific playing position [1]. Within the clinical field, a kinematic gait and motor coordination analysis was conducted on subjects affected by neurodegenerative diseases, especially in multiple sclerosis, by analyzing the joint angular displacement time and spatiotemporal parameters with a fusion method between surface EMG (sEMG) and a motion-capture system, using four optoelectronic cameras [10]. This Special Issue demonstrates a considerable extent of interest from the scientific community in the field, as evidenced by the high number of articles submitted. Of the seventeen articles submitted, only ten were accepted for publication after a rigorous peer-review process, with an acceptance rate of 59%, showing evidence of the growing interest in human performance analysis in sport and exercise. The Academic Editors would like to take this opportunity to express our most thankfulness to the reviewers for their hard work, and each of the authors that chose this Special Issue to present their researches. The authors declare no conflict of interest.