This article examines an overlooked aspect of Xenophon’s philosophy: the crucial role of lower body training in his conception of physical fitness as an essential component of education for both humans and animals. Three key questions guide this investigation. Why does Xenophon appear to prioritize physical over intellectual education? Why does he emphasize lower body training for humans, hounds and horses? What unifying concepts connect Xenophon’s ideas about physical fitness and education? The article argues that the parallels between the physical education of Spartan children, Socrates’ shoelessness and the training of hounds and horses suggest shared physical characteristics across certain species, leading to similar methods for developing bodily vigour. Moreover, it contends that ideal education (paideia) must not only begin with but also maintain continuous emphasis on strengthening the body’s support structure—feet and legs—hence the focus on exercises like walking and running. The analysis reveals recurring foundational concepts: toil (πόνος), endurance (καρτερία)—two core principles of Socratic ethics—good health (ὑγίεια), exercise (ἄσκησις/μελέτη), gymnastics (γύμνασις) and good physical disposition (τοῦ σώματος εὐεξία). This pattern, present in both Socratic and non-Socratic works, offers new insights into Xenophon’s coherent vision of the relationship between physical fitness and education.