It's specific to the individual. Someone shorter and heavier might run at 4.0. My minimum is about 4.5. All depends on leg length, fitness level, weight, yadda yadda.
hi! i think it's totally different for each person, depending on your fitness level, height, etc.
when i began running, i was content anywhere between 4.9 and 5.1.
now i feel it's almost harder to run slower than it is to run faster, and sit around 5.7 for the majority of my run.
i will often run next to taller men whose strides match mine, but they are going 6+! it's weird.
i believe that jogging/running is defined by a MOTION not a speed, if that makes sense. If you are moving in a jogging motion than you are jogging. Ive seen people walk at the speed some of you guys are defining as jogging....speed walking, but walking. its all in the form!
When I first started on the treadmill, I jogged at 3.2 mph - pretty lame, I know I'm now repeating the C25K program running at 5.0 mph and it's tough - I guess I'm just a really, really slow runner!
I agree with mkroyer, it's not about the speed it's about what you're doing! I can walk up to 5mph, but I can't jog there for very long. I'm working on my C25K now and I've been jogging at a 4mph. I'm also 5'2", so I'm waaaay short lol. I'm a fast, scurry-walker because all of my friends are tall, but a much slower runner.
I jog at 4mph for now. Hopefully it will increase! When I started walking I was at 2.5 mph, then 2.7, 2.9 and now I'm at 3.0-3.2 and my previous speeds feel so slooooow. lol So I'm hoping jogging goes the same way!
My treadmill is way scary, though, because the belt slips sometimes, just enough to make you lose your balance. So I have to hold onto the handles and that kind of impedes my jogging.