It may be over a decade old, but Million Dollar Baby made an indelible mark on my soul.
Hilary Swank's fierce screen presence still flashes before my eyes when a gym session gets particularly tough or the final leg of my weekend run feels just out of touch.
'To make a fighter you gotta strip them down to bare wood… make 'em forget even their bones,' says her coach Eddie.
It's that total immersion in the moment that captivates me most.
Problem is, I'm far too pain-averse to take a serious punch.
So if I'm not up to getting into the ring, I can channel Swank with the fitness accessory best loved by both Hollywood and real-life boxing champs: the humble skip rope.
My favourite challenge of the moment is to complete one crossover skip for every 10 straight skips – and to do this 10 times in a row without fatiguing or tripping up.
But to get even more from my skip rope, I love incorporating it as part of my full-body circuits for a time-effective and totally mobile workout.
Agility rope drills
Place the rope on the ground, stretched long from handle to handle.
Now don't touch it again.
Using the skip rope as a marker, complete a series of agility drills to improve coordination, elevate your heart rate and burn fat (hello lean boxerina's body).
Start with a split foot shuffle – jog over the rope from back to front as fast as you can, leading with one foot all the way down the length of the rope and back again.
On the way back, switch your leading foot.
Next up is your double foot shuffle.
Do the same, but keep your feet together as you hop over and back, moving laterally along the length of the rope.
Finally, stand over one of the handles and skater jump across the rope, moving towards the other handle with every jump.
Complete 10 lengths (there and back) of each drill for around 5 minutes of intense cardio.
Still using the lengthened skip rope as your marker, add a plyometric Tabata drill to the end of your workout as a powerful finisher. Complete 20 seconds of any of the following, rest for 10 seconds, then repeat 8 times for a total of 4 minutes.
Over-rope burpees: Complete a full burpee on one side of the rope, jump over to the other side and repeat back and forth.
Ski squats: Assume a low squat at a 45 degree angle to the skip rope, then power through your heels to jump across and land facing 45 degrees the other way.
Bunny hops: Straddle your hands either side of the rope and hold your feet together to one side.
Activate your core and jump into the air, softly landing with your feet on the other side.
You can raise your feet higher and fall slower if you're working towards handstand, or keep them close to the ground and move rapidly to really get the heart pumping.
Squat thrusts: Assume a plank position with the rope running underneath your bellybutton. Now engage your stomach and jump your feet to the same side of the rope as your hands.
As up-tempo as the act of skipping is, sometimes it's a great tool for slowing things down and focusing on strength work too.
There is no better core finisher than a crawl.
My go-to is a crocodile crawl: hold a low plank position on your elbows while you shuffle forward by bringing your right knee to your right elbow. Push forward, then repeat to the left.
You can do this along the length of the rope, aiming to keep the rope along the centerline of your body at all times.
Bootcamp approved circuits
As I run weekly bootcamps in Wimbledon, I'm always looking for great exercises to include in team circuits.
Any of these exercises will work well as an element of a circuit. As would traditional skipping.
While excessive jumping on the balls of the feet can cause tightness in the calves, incorporating the jump rope as part of a balanced circuit makes skipping a smart and effective exercise.
For best results, do double foot skipping after leg work and single leg skipping after abdominal work so the core is warm and engaged.
Brit Williams is the founder of Fit Brit Collective. Between training clients, running bootcamps and teaching classes across SW London's leading studios, she is proud to work with ELLE to bring you the latest fitness news, trends and advice. Her fitness philosophy is simple – the endorphins you earn have the greatest power to transform.