Resistance bands: which strengths to buy and what they really do

Five colours on the shelf, a number of kilograms printed on each, and no clear way to tell whether yours is the yellow, the green or the thick black one. Short answer: you don't need one band, you need two or three strengths — and the number on the packet isn't the load you're lifting.

A band doesn't give constant resistance. The further you stretch it, the harder it pulls. A band labelled "up to 30 kg" might pull 8 kg at the start of the movement and 28 kg at the end. That isn't a flaw once you understand it, but it changes both which strength you buy and how you plan your sets.

What a band actually has to have

The list is short because the product is simple. What separates a band that lasts two years from one that snaps in month three comes down to rubber quality, how the layers are bonded, and how the ends are finished.

• Even thickness and width along the whole length — no narrowing, no ripples.
• Layers with no air bubbles and no nicks along the edges; the edge is where a tear almost always starts.
• A stated resistance range (say 10–30 kg) rather than a single number.
• On handled tubes: the tube end mechanically clamped, not just glued, ideally with a nylon sheath.
• A door anchor with a soft stopper that damages neither the door nor the rubber.

The specs that matter and what each one means

Type

Three types cover practically everything. The long closed loop does the most work — pull-up assistance, bar work, full body. The 20–30 cm mini loop is for hips, shoulders and warm-ups. The handled tube with an anchor is the closest thing to a cable stack: presses, rows, arm work. For a flat, one long loop plus two mini bands covers most needs. A fuller comparison of band types and how long they genuinely last is a separate piece.

Width and resistance

• 6–7 mm — roughly 2–7 kg. Warm-ups, shoulder rotators, forearms, technique cues.
• 13 mm — roughly 5–15 kg. The most useful single band for upper body.
• 22 mm — roughly 10–30 kg. Rows, presses, pull-up help for lighter lifters.
• 32 mm — roughly 18–45 kg. Serious pull-up assistance, added resistance on the bar.
• 45 mm and thicker — roughly 25–70 kg. Almost exclusively pull-ups and barbell work.

Those figures are approximate and vary between makers because they're measured at different amounts of stretch. Judge a band by how it behaves in the exercise, not by the label. If pull-up help is the goal, a 32 mm band takes roughly 20–35 kg off at the bottom position — but you need a solid pull-up bar, properly mounted, before any of that matters.

Length

A standard long loop measures about 100–105 cm unstretched, so around two metres of rubber. The safe working range for latex is up to two and a half, at most three times its resting length. Go beyond that and the rubber ages fast.

A shorter band gives more resistance in the same exercise because you stretch it further. That's the cheapest way to turn one band into two strengths: stand on it with a wider stance, or wrap it once around your hand.

Material

Layered natural latex survives the most stretch cycles and returns to shape best. Synthetics are cheaper and perfectly acceptable for light bands, but lose elasticity sooner. A latex allergy is the one reason to go synthetic without thinking twice.

No rubber likes sun, heat, oil or the salt in sweat. A band left on a windowsill or in a car boot loses years of life.

Load rating and anchoring

With bands, load capacity isn't a figure on the packet — it's a question of what you hook them to. The hook, bar or post should hold at least double the band's resistance, because tension climbs sharply near full stretch. A door that opens towards you, a handle and a radiator are not anchors.

What bands genuinely do

For upper body they do the job: rows, presses, pulldowns, everything for shoulders and arms. Research generally shows that in untrained people and those returning after a break, bands produce strength and muscle gains similar to weights, provided sets are taken close to failure. That's where the evidence is strongest; for experienced lifters the picture is less settled.

For legs they're limited. Banded squats and deadlifts stop being hard quickly, because resistance is lowest exactly where the movement is hardest — at the bottom. For legs, bands work better added to a barbell than instead of one.

A workable frame: 3–4 sets of 12–25 reps, one or two reps left in reserve, two to four times a week. You add difficulty with a shorter grip, slower lowering, more reps or a stronger band — progressive overload still applies when the load isn't measured in kilograms.

Space and money, realistically

Space: about two metres by two, plus three anchor heights — low (near the floor), mid (waist to chest) and high (overhead). A decent door anchor covers all three. The bands themselves live in a drawer, which is their single biggest advantage over any other kit.

Cost tracks the amount of rubber and the number of layers. As a rough guide, a mini band set runs around £8–20, a single long loop £12–35 depending on width, a four-loop set £30–80, and a tube kit with handles, anchor and bag £20–60. The spread comes from width and length, latex quality, warranty and retail margin — not colour and not the number of exercises printed on the box.

Realistic lifespan is one to three years training three times a week, considerably less if you overstretch them or leave them in the sun. Cheap kit, but consumable: bands sit alongside cables and bearings among the things that break first in a home gym.

Common buying mistakes

• Choosing by colour. Colours aren't standardised; one maker's green can be twice another's.
• Buying a five-piece set of light tubes instead of two serious bands. Within a month everything is too easy.
• Buying the strongest band "to have room to grow". A 45 mm band is unusable for most upper-body work.
• Believing a stated 30 kg means 30 kg throughout the movement.
• Buying with no anchoring plan, so the band ends up on a door handle.
• Ignoring the first white marks along an edge — that's the cue to inspect, and to check how you're storing them.

Who they're worth it for

Worth it if you travel, work shifts, train in a small flat, are in your first 6–12 months of training, or simply need a proper shoulder and hip warm-up before heavier work. Worth it for advanced lifters too, but as a supplement to the bar and as a rehab tool rather than the main load. If bands are meant to carry most of your training, it pays to build the programme first and buy second.

Not worth it if you already have a fully kitted home gym with dumbbells and a barbell and you're chasing maximal strength only. And not worth it as your sole leg training if you're already strong — you'll wear out the rubber long before you wear out yourself.

When to see a doctor

A band that snaps under tension goes straight for the face. If it catches your eye and vision is blurred, it hurts, or you see blood in the eye, go the same day — this isn't one to sit on. The same applies to numbness or weakness in an arm that doesn't settle, and to joint pain lasting more than two weeks despite backing off the load.

In short

• Buy two or three strengths, not one and not a set of ten.
• For most people that means one 13 mm band, one 22 mm band and a pair of mini bands.
• Go thicker (32 mm and up) only for pull-up assistance or barbell work.
• The kilogram figure on the packet is the top of a range, not a constant.
• Don't stretch past two and a half to three times resting length, and keep the rubber out of the sun.
• Excellent for upper body, limited for legs, and best used with a clear plan for progression.