Ten years ago Efuah – whose name means "girl born on a Friday" in Ghana, where her parents come from – taught her first class in what was then a little-known form of exercise called pilates in a church hall in Redland.
Today, she runs a successful pilates studio with about 300 clients – and will be marking her decade of teaching with a 10-hour pilates marathon on Wednesday.
"I hadn't planned to teach pilates," revealed Efuah, who used to be a tutor on a social sciences access course.
"I'd injured my back after having my two sons quite close together – there is only 11 months and three weeks between them – and I'd been told by an osteopath that I needed to improve my core strength.
"When I started looking at ways of doing that, I came across something called pilates which was becoming popular in the States. I couldn't find any classes in Bristol, but I came across a course in London where you could learn to become a pilates teacher, so I decided to do that.
"As a result of learning pilates, I went from suffering debilitating back pain and being unable to pick my boys up to getting my health and my life back.
"Pilates transformed my health so dramatically that I wanted to show other people how to do it, so I booked the hall at Redland Parish Church, holding my first ever class there in January 2000."
Efuah's sons are now aged 15 and 14, and she has become one of the longest-established pilates teachers in the Bristol area.
"Everyone has heard of pilates nowadays, but 10 years ago hardly anyone knew about it," she said of the exercises devised by Josef Pilates, which target the deep postural muscles.
"I think the reason that pilates has become so popular in recent years is simple: it works. People can often see their body changing in a matter of weeks.
"But pilates isn't about being a perfect shape. The key thing is awareness of the body and how that impacts upon the posture."
As her reputation grew, and pilates became better known as a form of exercise, Efuah's classes became more in demand and she moved on from teaching body control pilates in the church hall near her Redland home. She started teaching at sports clubs and in April 2008 opened the Efuah Bonney Mind and Body Studio in Kellaway Avenue, which provides a range of complementary therapies in addition to pilates coaching.
"I really like the fact that a lot of the people who come to my classes have been with me since the early days, which I think must mean I'm doing something right," she said.
"I still take the approach that I have always done with new clients, which is to always take an extensive background and give them one-to-one teaching, initially to establish what is best for them.
"Some people want to join a beginners' class when they start, but I've found that often people think they are fit because they do a particular sport such as running, but they're not aware of their body and even a beginners' class could be difficult for them if they went straight into it, as pilates is a totally different type of fitness.
"Once they do join the matwork classes there are only eight people to a class. I do this because pilates is very precise and it's important for a teacher to be able to adjust clients so that they are doing it correctly."
Efuah has been marking her decade of teaching pilates in Bristol by having a number of special events at her studio, which will culminate in a 10-hour pilates marathon for charity on Wednesday.
"I'm feeling very positive about it," said Efuah, who will be raising money for Penny Brohn Cancer Care and Tree Aid.
"I've previously done a three-hour sponsored pilates session, and when I finished that I felt really good.
"This will be a lot more challenging, but I'm going to be varying it by attending two classes in the morning, then doing some routines on my own, ranging from beginners to intermediate to advanced. I will be attending two more classes in the evening, and I'm hoping that the others who are there will be able to encourage me as I reach the end."
For details about Efuah Bonney's 10-hour pilates marathon, or about the studio, go to www.pilatesbristol. co.uk or telephone 0117 944 1114.