The Effects of mHealth-Based Gamification Interventions on Participation in Physical Activity: Systematic Review - Linqi Xu; Hongyu Shi; Meidi Shen; Yuanyuan Ni; Xin Zhang; Yue Pang; Tianzhuo Yu; Xiaoqian Lian; Tianyue Yu; Xige Yang; Feng Li (JMIR mHealth and uHealth, 2022)