Oxhey boxer Romeo Romaeo exhibited his skipping skills in the intu Watford centre, ahead of a world record attempt later this year.
The 18-year-old super-featherweight is hoping to raise £100,000 for Great Ormond Street Hospital by jumping rope for a record-beating 35 hours.
The longest skipping marathon currently stands at 33 hours and 23 minutes. Competitors must skip solidly for an hour, with a one minute break.
Mr Romaeo said: "I have never really tested myself to see how long I can go. Normally for training I skip for 20-minute periods or maybe an hour - I did do a two-hour stint a while back - but skipping is something I love to do. Doing it for Great Ormond Street makes it that extra special."
"I’ve set that goal of 35 hours and when I set my mind to do something then I am determined to do it. Having that mindset, means my body will be willing to go through it.
"While I am doing this, I am still doing my fights so I’m trying to squeeze everything in. I didn’t want to stop to concentrate on one thing.
"I'm up at four o'clock every morning to go for a run and I train three or four times every day. I probably train for eight hours most days.
"I've been training since I was four-years-old. Training is my life and I love it. There's nothing I enjoy more.
"I train hard because I'm determined to be a world champion."
Mr Romaeo’s world record attempt takes place on July 18. If you would like to donate visit: http://www.justgiving.com/user/47226175