The current COVID-19 pandemic has paralysed whole countries, which have had to confine their entire population and this changed people’s lives worldwide. The aim of this study is to identify the reasons for and the level of commitment to physical activity among the Spanish population during confinement and the return to the “new normal”. A sample of 1025 amateurs, 534 males and 491 females with an average age of 35 years old were interviewed using an online survey that collected their motives for practising sport and their commitment to physical activity. A cluster analysis combining hierarchical and non-hierarchical methods was performed, identifying three groups of amateurs: High Commitment (n = 650), Moderate Commitment (n = 324), and Low Commitment (n = 81). The main motives shown by the different groups were psychological motives related to an improved or managed general or emotional well-being. Regarding commitment, all the groups showed higher scores in enthusiasm for physical activity than affliction from sport. The variables referring to gender, educational level and sports habits showed differences that enabled the identification of the different groups. These findings highlight the importance of conducting segmentation studies that provide specific population profiles to improve the action strategies of governments and specialists.