Heart-rate monitors, sleep trackers, high-altitude chambers, digital coaches—technology has revolutionized fitness in recent years. On the other hand, the basics of fitness will never change: If we challenge our muscles, heart and lungs, we’ll stay in shape—fancy tools or no.

That said, everyone—regardless of their comfort level with techie tools—can benefit from a little workout assist now and then. Here we suggest a fitness aid for every level of comfort with technology, from Luddite to technophile.

Low-Tech

For me, a hard-copy book is like comfort food: It makes me feel settled, warm and happy. If you’re in the same camp, check out Stay Fit for Life (DK, 2017) by ISSA-certified trainer Joshua Kozak, whom Google named one of YouTube’s top 10 trainers three years in a row. With 60-plus functional-training exercises, 20 workouts, three one-month workout plans (to align with goals such as strength, endurance, stability, mobility and posture) and excellent basic fitness tips, the book is ideal for those just getting started (or restarted) with working out. Large, clear, colorful photos demonstrate each exercise, complete with technique tips. Each exercise also has progression tips, showing how to make it easier or harder.

Mid-Tech

If books seem too old-school, download the Sworkit app, available for iOS and Android devices, as well as the web. Sworkit delivers 75+ prebuilt fitness videos for strength, cardio and yoga workouts that can be done anywhere, equipment-free. Choose your fitness level and workout length, and you’re off and running! You can also customize workouts, schedule workout reminders and tap into workout playlists, through Apple Music or Spotify. Tip: Splurge for Premium (seven-day free trial; then $30 for three months or $60 for a year); free options are rather limited. It might seem expensive for an app, but compared to a gym membership—or doctor bills because of poor health—it’s a pittance.

High-Tech

As a fitness geek, my favorite new toy is Activ5, an innovative fitness tool. Here’s the rundown: Activ5 is a small device—about the size of your palm—that pairs with an app (iOS or Android) and measures your force in various isometric contractions, which occur when you hold a muscle contraction (picture a wall squat). First you set a max-power baseline for each exercise, and then the app leads you through various workouts targeting different parts of your body, measuring your progress as you go. The workouts are about five minutes each and the device is easily portable, which makes Activ5 ideal for travel or midday office workouts, or for using while watching TV. If you need the distraction or motivation, you can also download video games that operate when you activate (squeeze) the Activ5. This isn’t the only workout you’ll need—it doesn’t do much for your cardio fitness, for example—but it’s an excellent complement to traditional workouts, and one you can slip in anywhere, anytime.

Kellee Katagi is one of those strange souls who actually enjoys working out for the sake of working out. She’s spent most of her 20-plus-year writing and editing career covering fitness, nutrition and travel, as well as outdoor sports ranging from skiing to spelunking to street luge (yes, that’s a thing).