From the blog:
There’s a reason why many people talk about their writing skill as a “muscle” that must be exercised if it’s to grow stronger. Honing your writing craft—not to mention working on the business/career side of writing—involves many of the same mental, emotional, and even logistical challenges that are connected to pursuing a stronger, healthier body and lifestyle. Fitness and overall health can be just as much a lifelong investment as writing.