Reasons for the Practice, Abandonment, and Non-Practice of Extracurricular Physical Activity and Sport Among Primary and Secondary School Students in Cantabria: What Can We Do About It?

(1) Background: Physical education at school is not able to meet the need for physical activity and sport (PA and S) established by international organizations, making it necessary to implement its practice outside school hours. This study aimed to find out the reasons for practicing, abandoning, and never having practiced PA and S outside school hours among students of Primary Education (PE) and Secondary Education (SE) in Cantabria (Spain). (2) Overall, 1038 students participated (349 from PE and 689 from SE), consisting of 512 boys and 526 girls between 10 and 17 years old (M = 12.92; SD = 1.92). They completed an ad hoc questionnaire with 21 questions about reasons for practicing (12 items), abandoning (3 items), and never having practiced PA and S (6 items) between the months of May and June 2024. (3) Results: As for active students, boys argue that they do so because of the influence of friends (<i>p</i> = 0.024), search for excitement (<i>p</i> = 0.002), liking PA and S (<i>p</i> = 0.022), and entertainment (<i>p</i> = 0.001). In PE, compared to SE, the most important factors are excitement (<i>p</i> < 0.001), health (<i>p</i> = 0.005), and liking PA and S (<i>p</i> = 0.022). Students who abandon PA and S do so because of the competitive environment (<i>p</i> = 0.001), with boys predominating. SE students highlight reluctance and laziness (<i>p</i> < 0.001) and the loss of liking PA and S (<i>p</i> = 0.013). Students who have never practiced PA and S do so because they do not find any sport motivating (<i>p</i> = 0.047) and because of reluctance and laziness (<i>p</i> = 0.018), especially among girls. In SE, the differences appear due to reluctance and laziness (<i>p</i> = 0.009) and because friends do not practice PA and S (<i>p</i> = 0.049). (4) Conclusions: Boys prioritize emotional and competency aspects, while girls focus on social aspects and happiness. PE students tend to participate in sports for fun and to improve their skills, while SE students tend to show reluctance and laziness and a loss of interest in PA and S.