Training outdoors is one of the classic human traditions. Almost every workout I do is outside, whether it’s weights at the outdoor gym, sprints on the beach, hikes, fat tire cycling on the beach, paddling in the ocean, pickle ball on the court or Ultimate on the grass. Being outside in the sun while you train and play means better results, more vitamin D, a bigger pump (from nitric oxide production from said sunlight), a stronger connection to the earth through barefooted grounding, exposure to all the benefits of nature, and it’s just more enjoyable. However, you can’t always train outside. Sometimes you need to bring the outside indoors. Sometimes you need indoor exercises.
What are some of the best indoor exercises?
Treadmill Uphill Ruck
One of the best overall exercises for building strength, endurance, and “grit” is the uphill ruck. You strap on a heavy pack (or weight vest) and go walking through hills. It’s easy on the joints, hard on the muscles, and is incredibly demanding of your cardiovascular system without forcing you to go fast. Uphill rucking is a great way for anyone whose joints won’t allow them to run or who simply doesn’t like running to still get great aerobic work in. But there aren’t any hills indoors.
A good indoor replacement is to use the treadmill on max incline. You pump the incline up to 15, strap on your pack, and go. Pick a speed that’s manageable but challenging. It’s arguably better in some ways than the real hills because you’re able to constantly climb and eliminate the flat portions. I’m not a huge fan of rucking on flat ground—it doesn’t feel terribly helpful.
The one thing it can’t replicate is the downhill portion, a vital part of the ruck session because the eccentric loading of the knee helps strengthen connective tissue and trains the muscle to “lower” the weight. Following up the treadmill ruck with some high rep VMO squats while wearing the pack or carrying weights is a decent approximation.
Treadmill Hill Sprints
You know the drill. Hill sprints are bar none the best sprints around. They’re harder, because you’re fighting even more gravity. They’re easier on the joints, because your feet aren’t “falling” as far. They’re more efficient than flat sprints, so you don’t need to spend as much time doing them.
Flat sprints on a treadmill have always felt off to me. For one thing, flat treadmill ambulation isn’t the same as flat ground ambulation. A 2013 study found major differences between accelerating on the treadmill and accelerating on the ground.1 Runners on the ground accelerate and modify their biomechanics to accommodate the acceleration, increasing hip joint power and reducing knee joint power. On the treadmill, the ground accelerates instead and the runner maintains the same “kinesiological mechanics.”
By increasing the incline, you can almost recreate the effect of running on real ground. According to one study, a 1% incline is enough to make running on a treadmill very similar to running on the ground.2
Most bear crawling happens on the grass or in the sand.
You can just as easily bear crawl around the house or the gym. In fact, whenever I remember to do it, I’ll spend 5-10 minutes crawling around my house. Upstairs, downstairs, into the kitchen, the bathroom. It’s a fun way to get around, it’s very good for shoulder mobility, and it’s actually a nice way to warm up before an upper body day. Try to keep your torso relatively level—parallel with the floor—and get most of your movement through the shoulder girdle.
To make this a real workout, you can crawl 10 paces, do 10 pushups, crawl 10 paces, do 10 close-grip pushups, and repeat indefinitely. Easy way to blast the upper body.
Balancing as you walk along narrow surfaces is a fun way to train and challenge your balance and vestibular systems, and it usually happens outdoors in nature. Logs across streams, fallen trees jutting out over a ravine with a 50 foot drop below, slippery backs of park benches, tree root systems with enough exposure you can traverse them,
While they aren’t as exciting as balancing on real surfaces outside, long pieces of lumber are relatively inexpensive balance beams that work great indoors. Just lay the pieces directly on the ground in whatever configurations you want. It’s also safer, since you’re not falling more than an inch or two if you mess up.
2×4 if you’re not very comfortable on a balance beam
2×3 if you are
1×2 if you really want to learn to balance
You can also use them for crawling—bear crawls along a 2×4 is a great exercise and surprisingly difficult.
Although I don’t do it so much anymore—the risk to reward ratio is too high for me and a fall would be dangerous—I used to love bounding from rock to rock down at the many creeks and rivers during my childhood in Maine. It’s a mix of explosive strength (you have to jump far and high), balance (you’re landing on and taking off from often unstable or narrow rocks), accuracy (you have to aim for a specific spot in the world and land there), and textural navigation (it could be slippery or wobbly or rough or slick or mossy). It also takes a bit of daring. And it’s fun.
To do these indoors, you can place weights, benches, boxes, and Bosu balls all over the floor and jump from spot to spot. Using a mix is best, as this provides different heights and stabilities. If you’re using weights, the Olympic weights work best. In a pinch, furniture can work too. Even a throw blanket or pillow on the floor can be a “jumping rock” (just be careful if it’s on hardwood). The important thing is having a target to aim for.
Once again, kettlebell workouts are best outside, but they also work well indoors. Why?
Kettlebells are compact. They take up almost no space, and the actual movement pattern of a kettlebell workout is also quite constrained. If you really wanted to, you could get a good KB workout in a large closet. Kettlebells are versatile. With just a single kettlebell, you can work every major muscle group. You can get a total body workout in about ten minutes.
Here’s a sample kettlebell complex:
10 goblet squats (legs, glutes, torso)
10 bent over rows, each arm (biceps, back)
10 swings (hamstrings, glutes, lower back)
10 overhead presses, each arm (shoulders, triceps)
Repeat 5 times.
You’ll be done in 10-15 minutes. You’ll be breathing hard. You’ll feel like you got a good workout, and you will have gotten a good workout.
It’s ideal to train outside, but we can’t always make it work. These indoor exercises are the next best thing to being outside in the sun.
Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.