Chris Norman, from the Boys' Brigade, told Premier's News Hour it is crucial children are able to participate in outdoor activities.
He said: "It's really important to be part of something outside of the school, outside of home where they can get involved in those type of adventures.
"Whether that's camping or going into a forest, or an area and doing some den building, or a treasure hunt, something a bit different really."
The National Citizen Service asked 1,000 young people about when they have fun.
Teenagers were asked their most memorable experience from the last 12 months:
- 27% of boys said playing a new video game
- 12% said watching a new series on Netflix
- 8% answered discovering the Faceswap app
It found half were afraid of trying new things, and a quarter said they preferred spending time indoors over outdoors.
The findings come as increasing numbers of young children are spending long periods of time on iPads, smartphones and computers.
Chris Norman said children sometimes do not get the opportunity to explore.
"We took a group to the Peak District in November last year, as soon as we entered the Peak District and they saw the scenery they were amazed by that. They'd never been before and then actually walking through the water and the river."
He went on: "An amazing adventure for them, something they'd never do - they live in London."
The National Citizen Service also asked 2,000 adults what was the most adventurous parts of their live; going on holiday for the first time without parents came highly on the list.
However, many of the adults asked said they thought that young people are more protected growing up today, compared to when they were children and teenagers.
Chris Norman told Premier the Boys Brigade tag line "is 'the adventure begins here'.
"So, for children and young people it's about starting on that adventure, seeing the outside world, engaging with people and different opportunities.
"For the Church, it's more about children and young people going on that journey with Jesus and finding out more about the Good News."
Listen to Premier's Aaron James speak to Chris Norman here:
