Answer
See explanation.
Work Step by Step
The frequency of a simple pendulum is $f=\frac{1}{2 \pi } \sqrt{\frac{g}{L}}$. The leg swinging to and fro can be modeled as a simple pendulum. A smaller length L increases the expected frequency of a dog’s strides.
Also, a dog with shorter legs must swing them at a higher frequency to keep up with its owner.
