There is so much to love about bodyweight exercises - They can be done anywhere, require no equipment, and it's an effective way for beginners to build body strength and practice proper form before adding weights. But probably the best thing about them is that they can be performed when you don't have access to the gym - which a lot of us currently don't!
Some might think bodyweight workouts aren't challenging enough, the exercises are just too easy. They can become easier as your body gets adjusted to the movements, but they are still very effective at burning fat and building muscle. In fact, The American College of Sports Medicine's Health and Fitness Journal published a study that found that high intensity bodyweight circuits are an efficient way to decrease fat and boost muscular fitness. 
Bodyweight training gets easier as you make progress (as with any training), usually when that happens, free weights are added to make it more challenging. Unfortunately not everyone has dumbbells or any type of weights at home. But.... There are 5 simple changes you can make that will help make your bodyweight training training routine more challenging so you can continue strength training and making gains without adding any weight!
Change your tempo
Most already know that performing an exercise fast and with less rest is harder than taking your time and resting in between sets. It gets your heart rate up, you feel the burn in your muscles, and you work up a sweat - That's why HIIT (high intensity interval training) is so popular. But doing the opposite, is just as good, and possibly even better...
Slowing down as you perform an exercise keeps your muscles under tension thus making it more intense. Taking it slow also forces you to actually think about what you're doing and focus on the muscle group you're targeting. This will help you to stay focused to help engage the right muscles.
Here's an example of doing bodyweight squats at a slower pace: Take 3-5 seconds to lower down into the squat position. Add a pause at the most difficult part of the move, in this case it'd be at the bottom. So once you're at the bottom count to two, then take 3-5 seconds to stand back up. Pause for a moment at the top and repeat.
By moving slowly through the exercise and adding a pause, you are increasing the time under tension. That pause causes the muscles to contract against resistance, making it stronger. If you really want to challenge yourself, experiment with slowing down on each exercise. The key is to move slowly, focus on the muscle groups you're targeting, and pause at the most difficult part of the move.
If you want to switch things up and have a more cardio-focused workout just speed up the tempo. Do this by decreasing the rest period in between each rep. Create a HIIT circuit by picking 4-6 of your favorite cardio bodyweight exercises and performing them back-to-back with no rest in between the exercises. Then repeat 2-4 times (rest in between each round for a minute).
Make them unilateral
Making an exercise unilateral just means shifting the bulk of the work to one side of the body. Think, single leg deadlifts or bulgarian split squats. Making an exercise unilateral adds an extra stability challenge because the base of support is smaller making it tough to balance. It forces you to work harder, and the result of that? Unilateral strength which leads to strength overall!
For example, a pistol squat is a more advanced variation of a bodyweight squat. It's more challenging because it is performed on one leg and with the other lifted off of the ground in front of you. It is difficult, but practice makes perfect! Once you can easily do squats (at any tempo) take a jab at the pistol squat, but work your way up to it. I suggest placing one or both hands on a steady object until you can perform it without any support.
Another great example of unilateral exercises is doing a one-arm plank. Simply get in plank position, lift one arm off the ground and hold it by your side while performing a plank. This will fire up your obliques and really engage them because your core is working harder to keep your body stable
Just remember, practice makes perfect. Unilateral exercises aren't easy, that's why it's on this list. So work your way up to them, make slight variations to help with your balance and coordination. You'll slowly build balance and unilateral strength and eventually be able to perform the exercise without any assistance!
Do more reps
This one is an obvious, but an easy way to make your bodyweight training routine slightly difficult - Add more reps or sets to make the same workout feel harder again. Doing this makes it more challenging because you're increasing your overall training volume and also putting your muscles under more stress than normal.
The point is to push your body to work a little harder than last time. Adding more reps and sets does the trick when you don't have weights!
Increase your range of motion
If you've ever had a trainer, or even just an encouraging gym buddy, then you've probably already heard the term "move through the full range of motion". Like pulling your chest all the way to the bar while doing a pull-up or lowering yourself into a deep squat (thighs parallel to floor). It can be tough, but it helps build muscle.
The muscles are usually the weakest when they're fully stretched, so by pushing yourself and working the muscles into that end range you're able to build strength effectively. Make it even more challenging and add some pulses at the end range before going back to the starting position. Pulsing 2-3 times will really fire up those muscles and make you realize that maybe you don't need to lift weights to get a decent workout 🔥 But pay attention to your body, the burn you feel should not be overbearing. It shouldn't feel sharp or stabbing, it should just feel like a burning sensation in your muscles.
This is challenging though, so as always, work your way up to it. Doing this puts a lot of stress on the joints and muscles so gradually increase the range of motion as you become stronger. For example, beginners can start by performing a partial squat. Do this by squatting down on a bench or box. Gradually lower the box until you're able to go all the way down without assistance. This strategy can work for other exercises as well. You should know your limitations, just remember to push yourself a little harder the next time you perform the exercise.
Add two or more movements
Combine two or more movements to one exercise - Or also known as, compound movements. These types of movements engage various muscle groups and it adds more motion for you to move through, making it more difficult to perform. It can be done by either combining two exercises or just adding a rotational or twisting movement to the exercise.
An example would be performing mountain climbers, but instead of moving your knees forward, you move each knee toward the opposite elbow. Thus making it slightly more difficult than you're used to. Another example is doing a pull-up, but add in knee raises to make you and your core work harder. Even simply adding a push-up to burpees increases the difficulty!
The bottom line is you don't need a fully equipped gym to reach your fitness goals! Having weights definitely helps, but not having any shouldn't stop you from exercising. Using your own body weight to workout can help with weight loss, build muscle, and even improve mobility. Another added benefit of bodyweight exercises is the variety they can bring to each workout! Having variety is a key part to any decent training program, the way to get better and stronger is by switching things up. So never stop adapting and try implementing a few of these changes into your routine to feel and see the difference!