The history of cricket conditioning reflects a gradual transition from traditional endurance-based training methods to scientifically structured aerobic conditioning programmes that integrate exercise physiology and sports science principles. This evolution has significantly influenced modern coaching practices, particularly in the development of young cricketers. Despite these advancements, limited empirical evidence has directly compared the effectiveness of sub-maximal and maximal aerobic training within the same Under-14 cricket population. Therefore, the present study examined the historical evolution of aerobic conditioning in cricket alongside the comparative effects of twelve weeks of sub-maximal and maximal aerobic training on selected body composition, physiological, and performance variables among Under-14 cricketers. Forty-five male Under-14 cricketers (N = 45) were randomly assigned to three equal groups (n = 15): a Sub-Maximal Aerobic Training Group (60–75% maximum heart rate), a Maximal Aerobic Training Group (85–95% maximum heart rate using interval training), and a Control Group that continued regular cricket coaching. Body weight, body mass index, body fat percentage, resting heart rate, VO₂max, heart-rate recovery, 30-yard sprint, Illinois agility, and Yo-Yo Intermittent Recovery Test performance were assessed before and after the twelve-week intervention. Data were analysed using one-way Analysis of Variance (ANOVA), Scheffe's post-hoc test, and Cohen's d effect size. The findings revealed that both experimental groups improved significantly compared with the control group (p < 0.05), while the Maximal Aerobic Training Group demonstrated significantly greater improvements in VO₂max, resting heart rate, heart-rate recovery, agility, sprint performance, and Yo-Yo Intermittent Recovery Test scores, with consistently larger effect sizes.