Training with a crew: what the research says about group exercise and consistency

September 28, 2026 · 6 min read

People who train surrounded by others skip fewer sessions — that is the classic finding in exercise psychology, and it is real. But association is not causation: the effect only shows up for real once someone designs the group to build a shared identity, not just whenever several people happen to sweat in the same room. And the newest, largest update to this literature found a much smaller advantage than the classic one.

The classic association: group cohesion and exercise adherence

The reference on this topic is Carron, Hausenblas and Mack (1996), in the Journal of Sport and Exercise Psychology. The three authors pooled, in a meta-analysis, the studies available at the time on social influence in exercise — important people in an exerciser's life, family, whoever leads the class, training partners, and two forms of group cohesion (social and task) — and how each one relates to adherence, intention to continue, self-efficacy and satisfaction. The effect size landed between small and moderate, from 0.20 to 0.50 depending on the variable.

The point worth flagging before celebrating: this is a meta-analysis of observational studies. It shows that people training in a more cohesive group tend to skip fewer sessions — it does not show that cohesion causes that consistency. There is an obvious competing explanation: people who are already more motivated to keep training also tend to draw closer to the group and describe it as more cohesive. Both effects — cohesion driving adherence, and motivation driving cohesion — point the same way when you measure the association, and the meta-analysis alone cannot separate one from the other.

Testing it for real: an actual group beats an arbitrary class

The people who tried to isolate the cause were Burke, Carron, Eys, Ntoumanis and Estabrooks (2006), in a meta-analysis published in Sport & Exercise Psychology Review that pooled 44 intervention studies — not observational ones — with 4,578 people in total. The studies compared different exercise-program formats: home exercise with no contact at all, home exercise with regular contact from a researcher, an ordinary group class, and a format called a "true group" — a class that received deliberate group-dynamics strategies to build a shared identity, such as common goals and structured interaction among members.

What set the "true group" apart from the rest. On adherence, the group built with cohesion strategies beat the ordinary group class. The ordinary class, in turn, did not differ from home exercise with contact — and both beat home exercise with no contact at all. In other words, sharing the same room was not enough on its own. What produced the advantage was building the group's identity on purpose, and that is something you design — it does not happen by itself just because a bunch of people train together.

The 2026 update calls for more caution

The most recent and broadest review of the topic, by Kritz, Riddell, Olsen, Harden, Burke, Ntoumanis and Thøgersen-Ntoumani (2026), in Nature Human Behaviour, pooled 71 studies comparing individual against group-based intervention across several outcomes. For the physical-activity outcome alone, the sample totaled 22,042 people, and the group's advantage over the individual format came out small and not statistically significant (g = 0.086, 95% confidence interval from -0.061 to 0.233).

That does not erase what Burke and colleagues found in 2006 — format still matters within the "group" category. But once the tally includes a larger, more recent set of studies, with virtual interventions and formats the 1996 literature never anticipated, the average advantage of group over individual training shrank and stopped being statistically reliable. The honest read here is that the evidence is divided — more solid for "a well-designed group beats an arbitrary group" than for "a group always beats training alone."

The crew challenge, without promising what the research does not guarantee

PulsoGym's crew challenge tries to sit on the sturdier side of the evidence: instead of just putting people on the same list, it gives them a shared goal and a scoreboard everyone can follow — the ingredient Burke and colleagues found actually made a difference, not the mere coincidence of training at the same gym at the same time. But the 2026 research calls for humility: no challenge replaces the motivation of someone who already wants to train. It only makes it easier for someone who is already close to sticking with it.