Zack George is an English CrossFit athlete who won the UK CrossFit Open in 2020 and was dubbed the UK’s fittest man that year. 🏋️
Since January 2024 he has also been known to TV viewers as “Steel” on the BBC’s revived Gladiators. His 300-rep challenge, though, is much simpler than TV makes it look.
It needs just three things: a rower, a pair of dumbbells and a box. No fancy gym, no special kit — just a lot of effort, spread over two rounds. 💪
Please read this first: this is a demanding, high-volume workout. Scale the weights, reps and box height to your level, stop if you feel pain, and get medical advice first if you are unsure whether it is right for you. This article explains the challenge — it is not a personal training plan, and it promises no result.
What Is the 300-Rep Challenge?
The challenge is a ladder workout. You work down through five stations, rest for five minutes, then work back up them in reverse order. 🔁
Each round adds up to 150: a 50-calorie row, 40 dumbbell squats, 30 box jump overs, 20 dumbbell push presses and 10 dumbbell burpee power cleans.
Two rounds of 150 gives you 300 — that is where the name comes from. The row is counted in calories, not reps, so think of it as 150 “points” per round rather than 150 strict reps.
The Workout at a Glance
Round 1 (down the ladder): 50-calorie row → 40 dumbbell squats → 30 box jump overs → 20 dumbbell push presses → 10 dumbbell burpee power cleans.
Rest: 5 minutes.
Round 2 (up the ladder): 10 dumbbell burpee power cleans → 20 dumbbell push presses → 30 box jump overs → 40 dumbbell squats → 50-calorie row. 🏁
Weights from the original challenge: 22.5 kg dumbbells each hand for men, 15 kg each hand for women. Treat those as the full version, not the starting point — lighter dumbbells are a sensible scale, not a failure.
1. 50-Calorie Row 🚣
The workout opens on the indoor rower, and pacing here decides the rest of your round. Go out too hard and the squats will feel twice as heavy.
Drive with your legs first, keep your arms long until your legs are nearly straight, then lean back slightly and pull the handle toward your belly button. Keep your shoulders down and avoid leaning far back, which can strain your lower back.
On round 2, this same row is the finish line — there is nowhere to hide, but there is also nothing left to save energy for. 😅
2. 40 Dumbbell Squats 🏋️
Hold a dumbbell in each hand, with at least one dumbbell head resting on your shoulders, and squat with an upright torso. Aim for hips below parallel, then stand fully at the top of each rep.
There are 80 squats in total across both rounds, so break them into small sets early rather than grinding to a stop. Short rests now are faster than one long collapse later.
If your form breaks down, lower the weight or the reps — depth and control matter more than stubbornly finishing at the full load. For more dumbbell work, see our dumbbells workout guide.
3. 30 Box Jump Overs 📦
Jump onto the box, then over to the other side — that is one rep. After tired legs from the squats, this station is as much about coordination as power.
Step down after each jump and pause briefly before the next one. Rebounding straight into the next jump raises the risk of a missed landing and sore ankles.
You do not need to stand fully tall on the box every time; staying low saves energy. And if jumping is not for you, step-ups over the box are the honest scale. ✅
4. 20 Dumbbell Push Press 💪
Your arms get a short break during the box jumps, but 20 push presses still bite when you are already tired. Break them up if you need to — two sets of 10 beats one failed set of 20.
Dip slightly at the knees with an upright torso, then drive up through your legs and press the dumbbells overhead until your arms are straight. Let the legs do the work; this is not a strict shoulder press.
5. 10 Dumbbell Burpee Power Cleans 🔥
This is the hardest station, and there are only 10 of them per round — small comfort when you are already exhausted. Start with the dumbbells at your sides, place them on the floor, and make room for your chest to touch the ground between them.
Jump your feet up beside the dumbbells, swing them between your legs with a neutral spine, then clean them to your shoulders. That is one rep — nine more, then rest (round 1) or the climb back up (round 2).
Keep the reps clean rather than fast and messy. A sloppy clean under fatigue is where backs and wrists complain loudest. 🛑
How to Pace It ⏱️
A useful approach is to treat round 1 as a strong but controlled effort — roughly 8 out of 10 — so you can match it or beat it on the way back up.
That is a pacing suggestion for readers, not a verified quote or instruction from Zack George himself. The old article attributed pacing advice to him; that attribution has been dropped because it could not be verified.
Break the big sets early, use the full five-minute rest, and sip water during it. Chasing a heroic first round usually just buys a miserable second one.
How to Scale It for Beginners 🌱
New to this kind of volume? Start with one round only, lighter dumbbells and a lower box. Step-ups instead of jump overs and step-back burpees instead of full burpees are sensible swaps.
You can also halve the reps — 25-calorie row, 20 squats, 15 box step-overs, 10 push presses, 5 burpee cleans — and build up over weeks. The challenge is still the challenge, just at your current level.
Stop if anything hurts sharply, if you feel dizzy, or if your form falls apart. Finishing slowly and safely beats finishing broken. For gentler conditioning ideas, see our fat-burning workouts guide.
What Equipment Do You Need? 🧰
An indoor rower, two dumbbells and a sturdy box or platform. That is the whole list — no barbell, no rig, no specialist machine.
Check the box is stable and will not slide before you start, and leave enough floor space for the burpee cleans. A clear, non-slip area matters more than any extra gadget.
Frequently Asked Questions ❓
How long does Zack George’s 300-rep challenge take?
There is no single official time, and this article does not invent one. Your time depends on your weights, your rowing pace, how often you break sets, and whether you scale it.
Use your first attempt as your own baseline, then compare future attempts against yourself — not against anyone else’s claimed time online.
What weights should I use?
The full version uses 22.5 kg dumbbells per hand for men and 15 kg per hand for women. Beginners should start lighter and only add weight when every rep stays clean through both rounds.
Can beginners try this challenge?
Yes, scaled — one round, lighter weights, lower box and step-ups instead of jumps. It is a demanding workout, so build a base of rowing, squatting and pressing first, and get medical advice if you are unsure.
Do I need a CrossFit gym to do it?
No. Any gym with a rower, dumbbells and a stable box will do, and a home setup with the same three items works too. The challenge is about the structure, not the venue.
What should I do after finishing?
Walk around, drink water, stretch gently and eat normally. Expect sore legs the next day or two — that is normal after 80 squats — but sharp or one-sided pain is a reason to rest and seek advice, not to push through.
The Final Word 🏁
Zack George’s 300-rep challenge works because it is simple: five movements, down and back up, with nowhere to hide and nothing to learn on the day.
It tests engine, legs, shoulders and grit in one session — and it rewards pacing and smart scaling far more than raw aggression. If you want a broader upper-body goal to train toward, our best V-shape exercises guide pairs well with this kind of conditioning.
And if you enjoy following how other athletes train at the top level, Roelly Winklaar’s recent training shows a very different, mass-focused approach to the same gym discipline.
So — scale it honestly, pace round 1, and leave the second-round row with nothing left. That is the whole challenge. 💪