The numeric suffix often indicates a catalog entry.
"Double Sets" is a common weightlifting technique. If "Alex" refers to a specific fitness influencer (like Alex Eubank or Alex Leonidas), the video might be part of a private training program or subscription site. Alex-Double-Sets-Challenge-18-2344.mp4
Filenames with this specific structure (Name-Title-ID.mp4) are often used for: The numeric suffix often indicates a catalog entry