Monday I have sled drags in the program but I do not have a sled. Through internet search I see walking lunges is a substitute. Would you agree? or suggest anything else?
While not as easy. You can get an old tire from the junkyard and chain it/strap it to your belt and walk around outside. You can even stuff 5s and 10s in the tire to make it heavier. People might think you are weird but who cares.