Using Smart Sensors to Monitor Physical Activity and Technical-Tactical Actions in Junior Tennis Players.

The use of smart devices to obtain real-time data has notably increased in the context of training. These technological tools provide data which monitor the external load and technical-tactical actions related to psychological and physical health in junior tennis players. The purpose of this paper is to monitor technical-tactical actions and physical activity during a current tennis competition in the Green stage using a Zepp Tennis Smart Sensor 2. The participants were 20 junior tennis players (under 10 years of age), with an average age of 9.46 years. The total number of strokes (n= 21,477) during 75 matches was analyzed. The study variables were the following aspects: (a) number of strokes, (b) ball impact in the sweet spot; (c) racket speed; (d) ball spin; (e) calories burned; and (f) match time. The current system of competition, based on knockout, does not meet the World Health Organization's recommendations for daily physical activity time. Players mainly used flat forehands with a lack of variability in technical-tactical actions which did not meet the current learning opportunity criteria of comprehensive methodologies. The competition system in under-11 tennis should be adapted to the players' characteristics by improving the variability and quantity of practice.