Reconstructing the Iglói system: historical insights and current relevance for distance running.

Introduction: Historical training methodologies in endurance running provide valuable insights for contemporary sports science. Mihály Iglói's interval-based system, highly influential between the 1950s and 1970s, produced numerous world records yet remains only partially understood. This study reconstructs Iglói's approach through historical sources, contextualizes it within modern theory, and evaluates its relevance to current elite distance running practices. Methods: A narrative approach was applied, combining Hungarian and English archival sources with a comparative review of contemporary peer-reviewed literature on international-level distance running training. Data synthesis identified continuities, divergences, and adaptable elements of Iglói's methodology. Results: Iglói advanced Gerschler's intervals into a complex, high volume system with up to 13 interval sessions per week. Training was primarily based on effort-based short repetitions (100-400 m), complemented by race-specific longer repetitions (600-1200 m). Sessions were organized into sets and sub-sets, interspersed with active recoveries and shakedown strides, while particular emphasis was placed on running form. The system was flexible and individualized, adapting to athletes' goals and event demands. Under this framework, athletes achieved 31 world records and numerous national titles. Discussion: Contemporary distance running training again heavily focuses on controlled longer and shorter aerobic intervals for improving lactate threshold speed (vLT2). From Iglói's system, re-adaptable elements include race speed-specific but controlled short intervals for aerobic conditioning, combined with harder repetitions, alongside the use of active recoveries and "flush" or recovery sets to enhance lactate shuttle mechanisms. Equally important is the emphasis on economic running form at different parts of the race, supporting both efficiency and tactical readiness.