Sports scientists say this free fitness app is one of the best to help you get stronger - here's what it's like

To get started, the app will have you select your gender and ask how active you are — information that it uses to recommend a few initial workouts.

Within the app, there's a range of possible activities, with some targeted towards beginners and others designed for people who already work out more regularly.

When you open the app, it's ready for you to start working out.

You'll see three tabs at the top of the screen that you can use to pick a workout.

You can choose a recommended workout, if you want to get started quickly. You can also scroll through the full list of workouts or set up a training plan.

Plans vary depending on how frequently you want to work out, whether you want to include running, and more.

You can also choose between programs that require access to gym equipment or programs that rely solely on body-weight exercises.

The eight-week gym strength-training program shown here, for example, is focused on building strength.

As the app notes, that program requires full gym equipment, and it's targeted towards people at an intermediate or advanced fitness level.

When designing your plan, you choose how often you want to work out. Most experts say you should work out at least three days per week to build strength, though you might make some progress with two days per week at the start of a program.

You'll also choose whether you want to include running, tell the app how often you normally workout, and you can input height and weight information to track your plan.

Before you begin a workout, you'll see some information about what you'll be doing that day.

You'll see the duration intensity, equipment needed, and what this particular workout helps you focus on (like power, leg strength, or sports performance).

In some cases, workouts are designed by various Nike-sponsored athletes.

While you're training, it's important to build up to harder things over time, but also to get enough rest.

That's why after a particularly intense week, your next week might be a bit easier.

If you miss a few days, the app will prompt you to adjust or update your plan.

During the workout, the screen will display a video showing how to do each exercise.

Through your speaker or headphones, a coach will explain how to do each exercise, giving you tips on how to position your body.

For rep-based exercises, you check off exercises within the app after each set of reps to note that you're ready to proceed to the next set.

On this page, you'll see workouts selected based on the workouts you chosen to do so far.

There's also a section for new workouts that have been added to the app, and for new workout collections. There is a set of six workouts to help runners improve, for example, and a set of six workouts to teach beginners some fitness basics.

Here, you can browse workouts by muscle groups — including abs and core, arms and shoulders, or glutes and legs — or by workout types, like endurance, mobility, strength, or yoga.

You can also filter options by fitness level, workout duration, intensity, and focus. And you can check out workout collections, which include options to train like certain athletes or to focus on something like toning your abs.

You can also seek out workouts that don't require equipment or are quick and short.

There are more endurance and strength workouts offered in the app than anything else.

If you star your favorites, they'll be accessible in the top right of the app at any time.

There's an option to link up to an Apple watch, beginner meditation tips from Headspace's Andy Puddicombe, a few "workouts of the week," and a way to shop for Nike gear.

You can also add friends here if you want to keep each other accountable or compete.

You can keep track of everything you've done here.

This goes beyond the workouts you do in the app. There's a section here to add other activities, like a hiking trip or a pick-up soccer game.

Not only does this section track workouts, it also gives you milestones to work towards, include total numbers of minutes spent working out.

Some of these events might not be easy to access. Nike events in New York City, for example, are limited to an intense (and not free, though reasonably priced) marathon training program for serious athletes.

The community challenge events, however, are open to anyone. You can even tag photos of yourself with Nike hashtags if you want them to show up here.

Push yourself hard when you want to go hard, but don't forget to take easier recovery days too — rest is an essential part of fitness.

But enjoy it.

Exercise is the closest thing to a miracle drug that we have, and if you're looking for an app to help you incorporate fitness into your routine, it's worth giving this one a shot.