How fast does one's foot move while walking?

Factual Questions
1

I stubbed my toe the other day, which made me wonder how fast my foot was moving when it hit the chair leg. Say I was walking 3 MPH. If each foot is stationary 1/2 of the time, does that mean the moving foot is swinging forward at 6 MPH?

2

If you’re walking so one foot is on the ground at all time, then half the time it isn’t moving (at least the toe isn’t which is touching the ground. So the foot that is moving must average 6 mph. It would be moving faster than that at midpoint of the stride, and some less when lifted from the ground or slowing to be placed on the ground.

3

I’m pretty sure the definition of walking - as a gait - is that one foot is always on the ground.

How much faster? I stubbed my toe at the midpoint of my stride.

Now - does relativity factor in? If someone is watching me from the side, and my body is progressing at 3 MPH, while my foot moves 6+ MPH, does it appear to move at 9 MPH?

4

That’s already factored in. Your planted foot is at 0 MPH, your body is moving at 3 MPH faster than that, and your moving foot is 3 MPH faster than your body.

5

During a normal walking gate, the foot is swinging forward ~1/3rd of the time, so the average speed of the foot would have to be 9 mph during that period. However, the foot is not at constant speed; it is stationary at the beginning and end of the swing. While the foot is not really a pendulum biomechanically, it can be treated as such as a first approximation for determining speed, so the peak speed of the foot would be 12-13 mph. At a brisk pace (4.5 mph), peak speed would be closer to 20 mph, or about the average speed of a trained punch. That is just at or slightly forward of the toe passing under the knee, when is generally where stubbing your toe is most painful; the foot slows down quickly after that. Most people heel strike when walking normally (especially in shoes), so the foot actually strikes at just about the walking speed with an abrupt halt, which is absorbed by the ankle and tibia, and transferred up to the pectineus and gluteus muscles to absorb the impact and stabilize the body while it continues forward to step on the opposite leg.

Stranger

6

What about special relativity? How much slower does time flow for your feet?

7

Ouch! No wonder stubbing your toe is so painful. I’ve absolutely shattered my toenail before, if my foot was going 20 miles an hour that’s no wonder!

8

It’s definitely going to age at a different rate, the good news is when you walk both feet get a turn.

9

I looked at 30 fps frame-by-frame stock footage of a side view of an adult male walking. His pace is medium. I measured the position of the front of the moving foot relative to the front of the stationary foot throughout the relevant part of one stride. I used background items to gauge the approximate height of the person, but this is a relative minor uncertainty compared to the overall speed of walking the OP is interested in (e.g., relaxing stroll vs. quick positional change vs. “I’m late!” pace, etc.). Anyway, the speed of the traveling foot in this example is actually fairly constant through much of the stride, at around 9 mph.