## 1 Introduction  
Working memory (WM) involves three independent central executive function components: shifting, updating, and inhibition [1]. The updating function changes the storage in the WM as new information appears. Substantial evidence has established that the WM is associated with learning, inference, problem-solving, and intelligence [2]. One of the most popular experimental paradigms investigating the updating function is the \"n-back\" procedure. An n-back task involves asking the subjects to monitor the identity or location of a series of verbal or nonverbal stimuli [3]. Accumulating research has provided evidence linking the updating function of the WM with the fluid intelligence of school-age children [2]. Moreover, previous studies have shown that the updating function in WM influences children's learning attainment. [PERSON] et al. [4] found that children with a specific difficulty at comprehending written text were less competent in performing updating tasks. [PERSON] et al. [5] showed that in comparison with normal children, children with mathematical learning difficulties have a relatively lower WM updating function. It was found that the WM updating function is plastic, especially in early childhood. [PERSON] et al. [6] demonstrated that the spatial WM is developed in children from five to seven years. [PERSON] al. [7] used the n-back procedure to train WM of preschoolers for 14 days and reported that the experimental group significantly enhanced their WM but the control group did not. However, most of these interventional studies involving WM training did not investigate the role of exercise on WM, especially on WM updating ability in young children. Aerobic exercises may be beneficial for both brain function and behavior performance of the WM in young children. Aerobic exercise refers to a type of exercise that provides energy through aerobic metabolism. The exercise duration lasts about 30 min or more and the exercise intensity is medium or above (60%-80% of the maximum heart rate value). Previous research has shown that acute aerobic exercises can shorten reaction time (RT) in the modified Sternberg WM task in young adults [8]. Acute moderate-intensity aerobic exercises were reported to also benefit preadolescent children's performance in the n-back task and enhance the neural basis of the WM [9]. Moreover, a longitudinal study has found that the level of extracurricular physical activity in four-year-old children can predict the performance of the 2-back task when they grow up to seven years old [10]. However, a meta-analysis with children aged 11-13 years reported no difference in the effect of various types of physical activities on cognition [11]. As an important type of exercise in early childhood, coordinative movements involving activations of multiple muscle groups refer to the motor-demanding exercise that involves activation of the cerebellum and motor control network and requires perceptual and high-level cognitive information processing [12]. Previous research has shown that the prefrontal cortex plays an important role in both cognitive functions [13; 14] and motor coordination [15; 16]. Moreover, the cerebellum affects the updating function of WM [17]. [PERSON] et al. [18] suggested that the cerebellum influences the medial frontal networks in animal models, and it further supports the neuronal structures responsible for coordination as well as working memory. Due to the neuronal connections between the cerebellum and frontal cortex, it is reasonable to postulate that cognitive performance, especially WM, is influenced by coordinative exercises. Coordinative exercises involve complex motor movements for goal-directed behaviors. The focus of attention during these exercises keeps changing. Individuals have to update the motor information rapidly during coordinative exercise, for example, the forehand and backhand stroke practice in tennis.