A PE-teaching mum is warning gym-goers to never do squats without safety bars after she was left paralysed when the barbell slipped and snapped her back.
Some girls who were in the gym heard the commotion and rushed over to help pull the bar off Henrietta while a member of staff called an ambulance who took her to Southampton General Hospital.
The PE teacher said doctors told her it is rare to be able to regain sensation in the spine after suffering an injury like hers.
The following day, the mum-of-two underwent an operation where five of her vertebrae were bolted together to stabilise her spine.
However she has been left unable to get around her own home so has now launched a JustGiving page in the hope of raising some of the £230,000 that is likely to be needed to convert her three-story house.
She is now warning others to never do gym squats without ensuring there are safety bars as the accident happened in a 'split second'.
Henrietta said: "I've done it [the squat] plenty of times before. It was just a normal day, I left the house at sort of ten to seven intending to come back in an hour's time and I haven't really been back since.
"It was terrifying. That was probably the most terrifying point of my entire life - that moment there when I knew what was happening, and there was nothing I could do to stop it as well, so it was awful.
"I think deep down I knew. I heard it, I obviously heard it go and felt my back break and people around me were obviously trying to keep me calm and saying things would be alright but I knew what I had done straight away.
"The pain was indescribable, there's nothing I can compare it to. It was the most pain I've ever experienced.
"100 per cent I should have been using squat safety bars and I have every other time I've squatted up until I started using this particular gym.
"This gym don't have any [squat safety bars] and it just became the norm not to use them but looking back, it's just a ridiculous idea to squat without them and I would say to anyone ever now just don't squat without safety bars.
"The surgery wasn't what worried me as much as just the damage I'd done to my spinal cord which they can't do anything about that. The surgery is just to fix the bone."
The accident happened on May 29 and after spending six weeks in Southampton General, Henrietta was moved to the Spinal Treatment Centre in Salisbury where she is still receiving treatment.
Henrietta still experiences a lot of discomfort with an aching back but is continuing her regular gym sessions where she works out her upper body.
She has always had a passion for sport and even competed in the pole vault at two commonwealth games before retiring in 2017 following a knee injury.
She is hoping to be able to return to work in January for the start of the new school term and said she is thinking about taking up a new sport such as wheelchair basketball or wheelchair rugby.
Henrietta said: "I just always knew I wanted to be an athlete, I wanted to go to the Olympics and be an athlete. That's all I wanted to do.
"I've got so much stuff still to do with my life, I'm not going to let this take hold and reduce the quality of my life, let alone the quality of my family's life. That's what kind of gets me up every day and keeps me going.
"On the whole you've just got to get on with it because life goes on and it'll go on with or without you so I'd rather be involved.
"There are days when it's really hard. There are days when you just think how on earth did I end up like this.
"A lot of the rehab is more centred around getting used to life in a wheelchair and being able to manage that, getting in and out of the wheelchair and daily living.
"But I believe that I'm doing everything I possibly can for my spinal cord to be able to regenerate in the best way it can.
"I'm doing everything I can to make sure if it's going to happen, it's going to happen to me.
"There's a lot of self-directed rehab. You've got to be quite motivated to get on and get things done.
"There's a lot of new skills to learn and a lot to get your head around. It's eye-opening how much you take for granted.
"Just things like putting clothes on is just an effort. You know, pulling shorts up and down, there's just so many little things that you're like, nothing's quick anymore is how I'd describe it. You can't just pop to the loo.
"I used to be a person who was a million miles an hour and impatient so this has been a learning curve, being forced to slow down."
A JustGiving page has been set up on behalf of Henrietta with a goal of £230,000 to help her pay for the unexpected cost of needing to adapt her home and private rehab once she has been discharged from the hospital.
Henrietta said she needs a platform lift fitted outside of her house because there are steps up to her front door and a through floor lift fitted inside so she can get between floors in addition to adapting a bathroom so she can use it.
She said she hopes the work will be done in the next six weeks and then she can be discharged from the hospital and return home.
Henrietta said: "It's a big target but I'm feeling hopeful.
"We know it's a lot, we don't get any grants to make the changes to our house, nothing at all. So we have to pay for all of that ourselves as well as any further rehab.
"It's a three-storey townhouse, which is just ridiculous. You couldn't have picked a more unsuitable house for a wheelchair.
"Because my long term goal is to stand again and to walk, if I want to chase that goal then I have to fund private rehab.
"That's not cheap but that's the way the system works.
"I think I've been overwhelmed by the support from friends and family. Although this has been the worst thing you could sort of imagine happening, it's showed me how amazing human beings can be and we've had so much love and support shown to us.
"We've got a lot to raise so honestly every little tiny bit is so greatly appreciated and does help so I just want to say a massive thank you to anybody and everybody who has already donated and might still donate.
"I have two small boys, they're three and five and I need to get back to them.
"I just want to be back with my family. I don't want their lives to be affected by my mistake and my accident. I don't want it to affect their opportunities or the things we do as a family."