Journal of Sports Sciences , 2021 (Volume 39, Issue 12)
It seems you are referring to — a term that could relate to a specific competition (e.g., over-40 veteran futsal leagues), a training methodology (e.g., 40-second drills), or a tactical concept (e.g., 40% possession rule). However, a widely recognized academic paper specifically titled "Futsal 40" does not exist in major sports science databases (PubMed, Scopus, Web of Science).
This study examined how different game durations (including 4-minute bouts similar to "40" if referring to 40-second intervals) and player numbers affect heart rate, perceived exertion, and distance covered. It found that shorter, intense bouts (e.g., 40-second to 1-minute drills) combined with active recovery improve anaerobic performance and tactical decision-making in veteran and elite futsal players.