Fitness classes seem to go in trends, and Zumba seems to be on the way down in my area (with BodyPump making its way up). Also, this time of year fitness in general seems to take a back seat - it's end of Summer, people are fitting in vacations and doing stuff with their kids while they're still home from school, it's hot/humid in many parts of the country, and we're about as far away from the New Years Resolution as we can get. The gym I go to (and associated classes) are always busiest in Jan/Feb and slowest between now and the end of the year. You and I know that fitness is part of life, but for many people it's something that they try once and then never follow up on again.
As far as the stuff you mentioned, how full is the class currently? If it should be 25 people, but only 10 are showing up, it can feel hard for a new person to "blend in" - which makes it difficult to get the numbers up again and it can feel more intimate and personal, which is NOT something I want in a group class. And a delicate question you don't have to answer - you mention the instructor isn't a size 0 (which is just fine! an overly fit instructor can be intimidating!), but is she overweight? Many people will not take a class or training from someone who is overweight, because they think "what could she possibly know about fitness?" And likewise, is the class overly slanted toward super fit people or mostly overweight people? People look for like-people, and if they walk in to a class where they feel they are above or below the average fitness level, they may look elsewhere for the next class.
I don't know if any of this helps, but it may explain why retention is a little lower, and give your friend ideas from there on how to combat it.
Do something everyday that your future self will thank you for.
| current weight: 176.0