Fitness is B.S.

Your regulars are your retention department. Lose one and others start attending less.
It's called the Peer Effect and a 2025 study of one gym measured it: for every visit you bring in, your members collectively add another 0.63 between themselves.

Fitness is B.S.

Our 8-week challenge is also 56 days and 40 sessions. But a 2026 study suggests the smaller we cut it, the longer the same eight weeks feel.
Telling a member 56 days is the same as eight weeks doesn't change how it feels. So the one who hits week five convinced they've been at it forever may be reacting to the sign-up page. Bigger units aren't automatically the answer.
I read the study and worked out which way to describe an 8-week challenge, where it holds its price, and when it makes no difference.
Full detail in the comments.

A 2026 study points at a reason new members drop out. It's not the members you'd expect, and it's part of why "too expensive" isn't always about the money.

A 2026 study found most of the attendance a gym challenge builds drops back after it ends. The members who came most during it often train less afterwards than they did before..
I read the study and worked out what to change in the last week of a challenge to hold that attendance, and what makes no difference.
Full detail in the comments.

Read the research on a reason behind the longevity of Les Mills classes in the comments

The "$0 joining fee" is the offer nearly every gym uses. But a 2026 study highlights the 0 might be the wrong word.
"Free" and "$0" are different, even at the same cost. So, the word we default to on our biggest campaigns is the one the research says underperforms.
I read the study and worked out where switching the word helps a joining-fee offer, and where it doesn’t.
Full detail in the comments

A 2025 study reveals a counterintuitive reason your most motivated members walk: they quit while they're still improving, and it has nothing to do with willpower.

I read through the research and wrote up what it means for a gym floor, including the change that keeps those members from drifting off.
Link's in the comments.

Fitness is BS. | Behavioural Science for Fitness Marketing Fitness is BS. Why gym members really leave. And what behavioural science says you should do about it.

BODYPUMP has been around since 1990.
A recent study into how people respond to "new" may help explain why it has stayed relevant for so long.
It also points at something about the classes we take off our timetables.
When attendance falls, has the class genuinely reached the end, or has it just become so familiar that members no longer notice it?
I looked at what the study found, what it might explain about the BODYPUMP release schedule, and whether a relaunch is worth testing.
Interested to hear whether anyone has relaunched a declining class rather than cutting it, and how it went.

Your free perks for best members aren't creating loyalty. There's research that shows why and how to fix it.
New research on reciprocity in unequal relationships explains the gap. I've broken down the MIT study and the specific move that turns comped perks into actual retention leverage.
Link to the blog in the comments section.

Full explanation in the comments