Arnold Schwarzenegger took to Reddit on Saturday to urge Americans to stay indoors during the COVID-19 pandemic and "focus on the things we do control," like our physical fitness. And you don't need fancy workout equipment or a streaming service to get a good workout, the former body builder said.

The 72-year-old explained that he's always found solutions to working out without a gym. Growing up in Austria, Schwarzenegger would do pull-ups from a tree branch and chop wood to build strength. Even as a fitness professional, he would run up the stairs of a hotel to exercise.

"By the end I was completely schvitzy and my legs got an incredible pump," he wrote.

"You don't need a gym to be fit," Schwarzenegger wrote. "I've written a program for all of you." 

Schwarzenegger suggests splitting up the number of repetitions into however many sets you need. For example, a "30 repetition" exercise could be split into three sets of 10 repetitions or two sets of 15. Having good form is the most important thing to focus on, Schwarzenegger wrote.

On that note, if you need to modify an exercise to make it easier, that's totally fine, he wrote. 

"Don't let your ego do the movements for you," he wrote. "You might want to show off to me or your friends and do 50 push-ups in one set, but if you can't do them with perfect form, I'll be more impressed by 5 sets of 10 perfect push-ups." Aim to do more repetitions each time you work out.

"Don't feel bad about working your way up to the full workout — we all start somewhere," he wrote.

Here are some of Schwarzenegger's exercises, plus some alternatives and tips from personal trainer Ben Lauder-Dykes, in case you're not quite ready to perform like The Terminator. 

Push-ups

All photos from @schwarzenegger Instagram 

Schwarzenegger's how to: Begin on your hands and knees, with your palms flat on the floor or a mat, shoulder-width apart. Extend your legs behind you, so your body forms a straight line from the top of your head to your heels. Lower your body and bend your arms until your chin or nose gently touch the ground. Keeping your abdominal muscles engaged and back flat, push your body back up to the starting position. Schwarzenegger suggests 25 to 50 repetitions.

Trainer tip: Just because the target number of reps is 50, doesn't mean you have to do that many, says Ben Lauder-Dykes, a NASM-certified personal trainer at the Fhitting Room, a boutique fitness studio in New York City. "If you're a beginner and you can only do 10, then you just keep doing 10, and it's more like a more like a framework," he says. 

Sit-ups

Schwarzenegger's version: Lie on your back with your legs bent, feet flat on the floor. (You can place the tops of your feet underneath a piece of furniture to keep them from moving.) Bring your hands to your hips or behind your head. Using your abdominal muscles, lift your upper body off the floor until you're sitting straight up, lower to the start. Do 30 to 100 repetitions.

Trainer tip: If you find that sit-ups hurt your lower back, the American Council on Exercise (ACE) suggests doing a plank instead. 

Bent-leg raises

Schwarzenegger's version: Lie on your back with your arms by your sides, palms facing down. Bend your knees so both legs form 90-degree angles. Bring your chin to your chest and curl up until the tips of your shoulder blades are touching the floor or mat. Extend your legs until they're completely straight, then return to the starting position. You should feel this exercise in your abdominal muscles. Do 25 to 50 reps.

Trainer tip: To make it easier, though, you can keep your legs slightly bent at the end of the exercise, according to ACE. 

Bent-over twists

Schwarzenegger's version: Stand with your feet wider than hip-width apart. Hold a broom or pole behind your head to keep your chest broad. Bend over and twist your left arm to your right foot. Return to stand, repeat to the other side. You can also do this exercise with your arms extended to the side, sans broom. Schwarzenegger suggests 25 to 50 repetitions.

Trainer tip: Twisting and rotating the spine in a bent-over position can be tough for many people, because it requires a lot of flexibility, Lauder-Dykes says. A better option for beginners would be simple side planks, he says. 

Squats

Schwarzenegger's version: For this squat, Schwarzenegger positions himself with his heels raised on top of a sturdy book. Stand with your feet hip-width apart (or wider if you need more stability), then sit back as if you're sitting in a chair. Squat down until your hips are below the knees, then return to stand. Schwarzenegger suggests 20 to 70 reps. 

Trainer tip: While this might look funny, elevating your heels provides more ankle mobility so you can lower deeper into the squat, Lauder-Dykes says. "It takes a little bit getting used to, but it is probably the best form of the squat for most people that I see," he says. You can also use a yoga wedge instead of a book.

Calf raises

Schwarzenegger's version: Stand with your toes on the same sturdy book you used for the squat, so that your heels hang off slightly. Lift your your left leg and balance on your right foot. Raise your right heel, then lower back down. Repeat on the other foot. Do 20 to 50 repetitions. 

Trainer tip: "Calf raises are pretty old school," Lauder-Dykes says. This exercise can also be done on a step; just make sure you have something to hold onto to keep your balance.

Chin-ups

Schwarzenegger's version: You'll need a chin-up bar for this exercise. Stand under the bar and grab onto the bar so your palms face away from you. Bend your elbows, and pull your body up until your chin passes the bar. Slowly lower down to the starting position. Schwarzenegger suggests 10 to 30 reps. 

Trainer tip: The biggest misconception about bodyweight training is that it's somehow inferior to, say, lifting heavy weights or taking a workout class, Lauder-Dykes says. But don't under-estimate the power of simple bodyweight moves like a pull-up; you'll still be building muscular strength and endurance, he says.

You can check out Schwarzenegger's full workout plan on Reddit. 

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