Don't Be Prey. Release date - March 20

Cert - 12, Run-time - 1 hour 31 minutes,

Director - Jeff Tseng

After losing himself in personal and financial struggle Mark Sowerby takes on the Oceans Seven challenge, swimming across seven open water channels across the world.

Film can show off the scale of mountain heights easily enough, Free Solo comes to mind. What it can perhaps struggle to do as well is show the vastness of a sea or ocean. We can, however, still see the physical toll that hours of swimming across a channel can take. The exhaustion that causes someone to slightly lose themselves even as through swimming they try to find themself. It's the case for Mark Sowerby, a former investment firm owner who stepped down to spend more time with family, with the company collapsing due to short-selling not long after.

In the wake of this Sowerby escalates his passion for swimming and takes on the Oceans Seven challenge; swimming seven vastly different open water channels across the world. It's something less than 40 people have accomplished so far, with there being plenty of dangers in each. Yet, what drives Mark, and many others, alongside the goal of the challenge is often something more personal.

Documentaries such as this can often feel repetitive, both with the swimming and stories. But, alongside the obstacles (from freezing temperatures to jellyfish and cookiecutter sharks) we hear enough that's different from each figure throughout the 90-minute run-time about what the challenge represents for them.

In fact, I would have liked to hear more from these faces. There's a good few minutes around halfway through where we hear stories of personal weights and negative memories that open water swimming has helped to put aside and deal with. They're largely glimpses, but still bring more to the journeys that form around the challenge, including for Mark's trainer Tim Denyer, also highlighting the preparation that goes into each swim. We hear of the technical aspects of the Oceans Seven from creator Steven Munatones. Through these points there's a successfully rooted story beyond the base challenge, which still prominently features and maintains general engagement.

Mark and wife Heidi have a phrase which crops up towards the closing stages, 'it only takes on day to change your life.' It's something which the film lightly touches upon in its closing points, but feels as if it could feature more prominently in ideas of finding yourself again amongst the mental and physical challenge of marathon swimming.

Drive for recovery is a shared theme amongst those taking on the challenge. Some of the most engaging moments are those where this is talked about, including recovery from swims. There's an intrigue in the physical and technical nature of the challenge, just how much is gone through over multiple hours and the reminders of the danger at hand. Jones with the personal backings which avoid repetition, there's a solidly engaging personal sports documentary here.

Four stars