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The Century BOB punching bag is the free-standing dummy you've seen in karate schools, self-defense classes and MMA gyms: a lifelike head and torso on a round base you fill with water or sand. BOB stands for Body Opponent Bag, and its whole point is targets. Instead of hitting a cylinder, you aim at a chin, a nose, a throat and a rib cage.
The verdict up front: BOB is the best-known body opponent bag for a reason, and for accuracy, self-defense and martial arts drills it does something a heavy bag can't. It's not a power bag, and it's not cheap. Here's what you get, which version to buy, and when a heavy bag or a Wavemaster is the better spend.
Our top picks at a glance
Who the BOB Punching Bag Is For
- Self-defense and krav maga students who need to practice strikes to specific targets.
- Karate, taekwondo and MMA practitioners working on precision and combinations.
- Families with different heights, since the original BOB adjusts across seven settings.
- People who can't hang a bag, because the base needs no drilling or mount.
It's a poor fit if you want to sit down on power punches for round after round, or if you mainly throw low kicks.
Think of BOB as a second bag rather than your only one. Many boxers and martial artists pair it with a hanging heavy bag: the heavy bag for power and conditioning rounds, BOB for accuracy, combinations and self-defense strikes. If you can only buy one bag and power is your goal, start with the heavy bag. Our punching bag vs BOB comparison explains the trade-offs.
Key Specs (Verified)
Figures come from Century's product pages for each model.
| Spec | BOB (original) | BOB XL |
|---|---|---|
| Height | 60" to 78", seven settings | 60" to 78" in specs (description says up to 82") |
| Weight | About 250 lb with water-filled base | About 250 lb with water-filled base |
| Base | Fills with water or sand | 24" diameter x 19.5" tall, water or sand |
| Mannequin size | Not published | 42.5" tall, 22" at the shoulders, 12" deep at the chest |
| Skin | Lifelike vinyl "skin" | Synthetic |
| Main use | Punches and strikes | Longer torso adds kicks |
| Warranty | One-year warranty on all BOB training mannequins, per Century | One-year limited warranty |
| Amazon | Check price |
Century's BOB XL page gives the top height as 78 inches in its specs and 82 inches in its description. We use 78 as the safe figure. BOB is an oversize freight item, and Century passes return shipping costs to the buyer, so be sure of your choice before you order.
What BOB Does Well
Real targets change how you train
Hitting a heavy bag teaches power and conditioning. Hitting BOB teaches you where to put that power. Because the head, jaw and torso sit at human proportions, you start to aim: a jab to the nose, a hook to the jaw hinge, a body shot under the ribs. For self-defense training, that accuracy is the point. For boxers, it helps with picking shots in combinations.
Height that fits nearly everyone
The original BOB adjusts in seven steps from 60 to 78 inches. That covers a 5-foot teenager and a 6-foot-plus adult on the same bag, which is a big reason martial arts schools use them. Set the chin at your own chin height, or a little higher if you train for taller opponents.
No drilling, no ceiling, no stand
Like any free-standing bag, BOB needs only floor space. Fill the base, set the height and train. Century describes the XL's base as rounded for easy relocation, so you can tip it and roll it out of the way when you're done. Put it on a grippy rubber mat, though, because smooth floors encourage sliding.
A useful accessory range
Century sells add-ons for the BOB family. The BOB Jacket attaches to the original BOB and the BOB XL with three rear buckles and four hook-and-loop tabs, and adds simulated arms and a body layer made of vinyl and high-density polyurethane foam. That lets you practice working around a guard, parrying and striking over or under arms, which a bare torso can't teach.
Where BOB Falls Short
It isn't a heavy bag
BOB is denser and firmer to hit than a foam-filled column, and it doesn't swing like a hanging bag. That's fine for crisp, accurate shots. It's less fine for long, hard rounds, where a forgiving heavy bag protects your wrists and knuckles better. Wear gloves or wraps for anything beyond light technique work. Century says it can be used with or without gloves, but bare-knuckle work on a firm surface is how wrists get hurt.
No legs
There are no legs below the torso, so low kicks and knee drills to the thigh have nowhere to land. The BOB XL's longer torso helps with body kicks, but a long Muay Thai bag or a Wavemaster column is the better kicking target.
The base moves under hard work
About 250 lb of water is a lot of ballast, but owners of free-standing bags in general report creeping and rocking under hard combinations. Filling with sand instead of water adds weight. Be aware it's much harder to empty if you move house.
Premium price for a specialty bag
BOB sits in the premium tier for a free-standing bag. If you mainly want a bag to hit hard for fitness, the same money buys a very good heavy bag and stand.
Strengths
- Lifelike head and torso targets
- Seven height settings, 60 to 78 inches
- About 250 lb with a water-filled base
- No drilling or mounting
- Accessory jacket adds arms to work around
Weaknesses
- Firmer and less forgiving than a heavy bag
- No legs for low kicks
- Can rock or creep under hard combinations
- Premium price; buyer pays return freight
BOB vs BOB XL: Which Should You Buy?
The two share the same idea, the same height range in Century's specs and the same roughly 250 lb water-filled weight. The difference is the torso. Our Century BOB vs BOB XL comparison goes through it spec by spec.
Choose the original BOB if you mainly punch and strike with your hands: boxing combinations, self-defense strikes, elbows to the head. It's the classic version and the lower-priced one.
Choose the BOB XL if you also kick. Century gives the XL a longer torso "for more training options, including kicks," and publishes its mannequin as 42.5 inches tall, 22 inches across the shoulders and 12 inches deep at the chest. The longer torso also moves body shots down to a more realistic height for taller users.
Other BOB versions
- Bobby Bully is Century's youth version. It adjusts from 50 to 55 inches and weighs about 170 lb with a water-filled base. Our punching bags for kids guide compares it with softer options.
- Versys VS.BOB puts a BOB head and torso with simulated arms on a tripod with a sand-weighted base. Sand is sold separately.
- Wall Mount Boxing BOB mounts flush to the wall for punching drills. Century says it's not designed for kicks or knees. Wall mounting has its own structural rules, covered in our heavy bag wall mount guide.
Setting Up a BOB Punching Bag
- Choose the spot. Leave room to circle the bag and step back. A rubber gym mat underneath reduces sliding and protects the floor.
- Fill the base completely. Century's 250 lb figure is with water. Use a funnel for sand. Don't overfill, and make sure the cap is fully sealed. An owner review on Century's own page says the cap is not leak-proof, so check for seepage after filling.
- Set the height so the chin sits at your target height.
- Lock the mannequin to the base and check it's tight before your first round, then recheck regularly.
- Start with technique rounds, then add power.
If your bag will live in an unheated garage, keep in mind that water expands when it freezes, which can stress a plastic base. Follow Century's guidance on fill materials.
Five BOB Drills to Start With
BOB earns its place when you train with targets in mind. These drills work for boxing, kickboxing and self-defense students alike. Keep the pace controlled at first, and wear gloves or wraps.
- Target jabs (3 rounds). Jab the nose, the chin, then the solar plexus, calling the target out loud before each punch. Accuracy first, speed second.
- Jab, cross, hook to the jaw hinge. Finish every combination on the side of BOB's jaw, then step off at an angle instead of straight back.
- Level changes. Alternate a straight punch to the head with a hook to the ribs. A real torso shows you quickly whether your body shots are landing too high.
- Self-defense strike chains. Palm strike to the nose, elbow to the jaw, knee to the midsection. On the BOB XL, add a body kick to finish.
- Defense and return. Set a timer for random beeps, or have a partner call "now." On each cue, slip or roll as if BOB punched, then fire back a two-punch combination.
Three to five rounds of two minutes each, mixed into a regular bag session, is plenty. For a full routine to slot these into, try our heavy bag workout, swapping the last rounds for BOB work.
Care and Maintenance
- Wipe the skin after each session. Sweat and dust build up on vinyl, and a damp cloth with mild soap keeps it clean.
- Check the mannequin-to-base connection before each round. A loose connection makes the bag wobble and wears the stem.
- Inspect the base cap for seepage every few weeks if you used water.
- Keep it out of direct sun when you can, since long UV exposure is hard on most vinyl.
Alternatives to the BOB Punching Bag
- Want a kick-friendly free-standing bag? The Century Wavemaster family has long foam columns made for kicks. See our Wavemaster review.
- Comparing every free-standing option? Our best free-standing punching bags puts BOB XL alongside six other no-drill bags.
- Want other human-shaped dummies? Our dummy punching bag guide covers BOB alternatives.
- Training mainly for power and conditioning? A hanging bag from our best heavy bags list is the better tool.
How We Researched This Review
We researched rather than tested BOB. We used Century's product pages for the original BOB, BOB XL, Bobby Bully, Versys VS.BOB, Wall Mount BOB and BOB Jacket for every spec in this review, and we compared them with other free-standing bags. We also looked for consistent themes in owner feedback, such as base sliding and fill-cap seals, and at how martial arts schools typically use body opponent bags. Where Century's own pages disagree, as with the BOB XL's top height, we report the more conservative figure.
FAQ
What is a BOB punching bag?
BOB stands for Body Opponent Bag. It's Century's free-standing training dummy: a lifelike head and torso on a base you fill with water or sand, so you can aim strikes at a jaw, nose, throat or ribs instead of a plain cylinder.
What is the difference between BOB and BOB XL?
The BOB XL has a longer torso, which Century says adds training options including kicks. Both adjust from 60 to 78 inches per Century's specs and weigh about 250 lb with a water-filled base. The original BOB is mainly for punches and hand strikes.
Should I fill a BOB base with sand or water?
Century says the base takes either. Water is easier to fill and drain, and Century's 250 lb figure is for water. Sand is denser, so the same base weighs more and rocks less, but it's much harder to empty if you move the bag.
Can you kick a BOB punching bag?
You can throw kicks at the torso, but Century positions the original BOB for punches and strikes, and the BOB XL's longer torso for kicks. Neither has legs, so low kicks need a long heavy bag or a Wavemaster-style column.
Is BOB good for boxing?
It's good for accuracy and head movement drills, but it isn't a replacement for a heavy bag. A BOB is firmer and shaped like a person, so full-power hooks for three-minute rounds are better done on a hanging heavy bag.
Verdict
The Century BOB is the body opponent bag to beat for target practice: lifelike, adjustable from 60 to 78 inches and stable at about 250 lb filled with water. Get the original BOB for hand strikes and self-defense drills, or the BOB XL if you kick. If what you really want is power and conditioning, spend the money on a heavy bag instead, and add BOB later as a precision tool.
