Halle Berry, 51, swears by workouts with resistance bands but ... how, exactly, do you use them?

There are some things in life you can always count on, like that there will be a Starbucks on every corner and that Halle Berry will always look utterly amazing.

Berry has made it very clear that she works hard to be fit, and she has been sharing tips and tricks from her workouts on Instagram lately. In her latest fitness post, Berry appears to be running while her trainer, Peter Lee Thomas, trails behind, holding on to a band that’s wrapped around her waist.

Berry revealed in the caption that the two are using “very inexpensive” resistance bands. “I want to build strength while staying long and lean. I never want to bulk up so I rarely use traditional weights,” she says. “These bands are so easy to carry that they allow me to exercise wherever I go. I can work out in my trailer while filming, in my office, on vacation in a hotel room, at the beach, in my living room or just about anywhere.” The bands are also helpful if you want to build muscle mass, she adds.

Resistance bands aren’t a new fitness tool — they’ve been used by fitness trainers and physical therapists for years, especially when it comes to helping people recover from injuries, Jim Pivarnik, PhD, a professor of kinesiology at Michigan State University, tells Yahoo Lifestyle.

At their core, resistance bands are used to help provide resistance to a particular movement, Pivarnik says. “If the resistance is significant compared to the strength of the person doing the work, the person’s muscles will get stronger, simple as that,” he says. It’s also generally thought that you’re less likely to injure yourself with resistance bands versus weights, Pivarnik adds.

Just like weights, there are a lot of different options for using these bands, Doug Sklar, a certified personal trainer and founder of New York City-based fitness training studio PhilanthroFIT, tells Yahoo Lifestyle. “Resistance bands are tremendously versatile,” he says. You can use a band to add resistance to your squats, anchor a band to a table and use the resistance in your leg lifts, do bent-over rows with a band under your feet, rope one around your shoulders for a harder-than-normal push-up, and more. They can also be used for bicep curls, tricep extensions, overhead or seated rows, and shoulder presses, Sklar says.

When it comes to picking out a band, Pivarnik recommends looking for one that provides good resistance, but not too much. And, if you’re hoping to progress, it’s a good idea to buy them in different strengths so you can adjust to a band with more resistance as you get stronger, he says. Another tip: They’re usually color-coded for strength, but every brand uses different colors, so it’s important to read the label, Sklar says. They’re also a good (and inexpensive) investment. “If you take care and don’t abuse or overstretch them, they should last quite a while,” Sklar says.

If you want to get into resistance band training and you’re not exactly sure where to start, try asking a trainer at your gym for pointers. A trainer should be able to help get you on a routine that you can build on.

Read more from Yahoo Lifestyle:

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