Here's an illustration I did a while back for Runner's World Magazine July Issue. It was for their Ask the Expert Column. I had to come up with drawing concepts to demonstrate that pushing a running stroller adds additional training benefits.
One benefit is the strengthening of certain muscle groups. To convey this, I had the wheels drawn like weights. Here are the other sketches I came up with.
I had some time so I worked the composition more.
And here's the final illustration.