8 Ways to Make an Exercise Harder Without Buying Heavier Dumbbells

Whether you want to build muscle, endurance or power, making tweaks to your exercise routine can make a big difference. The good news? You don't even have to spend money on buying heavier dumbbells (or other weights) to increase the intensity of your exercises.

Adding new elements into your workout is important, as it helps prevent plateaus and exercise boredom. Switching up your exercise routine has been associated with having more motivation to work out and follow through with their workouts, as seen in a December 2019 study in ​PLOS One​.

Even if you don't drastically alter your exercises, making a few tweaks to your routine may be the motivation you need to stick with your workout.

Try out these eight expert-backed ways to make your exercise routine harder and get the maximum benefit from your workout — such as changing your speed, adjusting rest times and even adding pulses — with no new workout equipment required.

"Changing the tempo and cadence that you perform an exercise can influence how challenging the exercise will be," Grayson Wickham, DPT, CSCS, founder of Movement Vault, tells LIVESTRONG.com. "When you decrease the speed at which you perform an exercise, you are typically going to make it more challenging. This is especially true for the eccentric phase of the exercise."

A quick refresher: The eccentric phase of an exercise is the lowering part of the move — extending your arm during a biceps curl or lowering down into a squat or push-up, for example. The concentric phase is the opposite — when you shorten the muscle by flexing your arm during a biceps curl or standing up from a squat.

"On the other hand, increasing the speed at which you perform the exercise can also increase the difficulty of the exercise," Wickham says. "In this case you are using explosive movement to perform the exercise as quickly as possible. This is going to increase the emphasis of the exercise to create power and explosive speed."

Wondering what the best exercise speed is to meet your goals? While more research is needed, so far, it looks like doing a movement slower in the eccentric phase and faster in the concentric phase may be the most favorable combination for increasing muscle size, according to a May 2021 review in ​Sports Medicine.​ For example, with a biceps curl, you would extend your arm slowly down and flex your arm up at a faster pace.

However, a faster exercise tempo overall (for both the eccentric and concentric phase) is thought to lead to greater strength gains, per the review.

If you have been doing the same number of reps for quite a while, it may be time to switch it up.

"Adding repetitions to a working set for a given exercise above and beyond what you normally perform will increase the intensity and demand on the muscles that you are working," Wickham says. "You can add as many reps as possible while still maintaining good form and technique."

If you have a specific objective in mind, however, you can adjust the number of reps for maximum benefit, according to the American Council on Exercise (ACE).

If your goal is to tone up and add muscle definition, you want to do reps until fatigue with a heavier weight — meaning the last rep should be very difficult to do. Aim for 8 to 15 reps.

Want to increase your endurance? Use lighter weights for a higher number of reps. You don't need to work until fatigue. Plan on doing at least 12 reps, if not more. Don't rest too long between sets, either.

If you're looking to build strength, you need to be fatigued after no more than 6 reps — which means the weight may need to be heavier. If your dumbbell feels too light, hold two dumbbells or two weight plates in one hand.

You may not pay much attention to how much time you rest between sets, but adjusting this time is a great way to break out of a plateau and help you meet your goals.

"Shortening your resting time between sets places a bigger demand on muscular endurance, as your muscles have not had adequate time to recover before your next set," Wickham says. "This can be a good technique to change up the stimulus and demands you are putting on your muscles if you are not accustomed to it."

The optimal rest time is determined by your exercise goals.If your goal is building muscle, keep your rest period between sets short (0 to 60 seconds) and use heavy weights, according to the National Academy of Sports Medicine (NASM).

If your goal is to burn fat, your rest period between sets should be slightly longer, 0 to 90 seconds, to keep your heart rate up.

Lastly, if you want to increase strength or power, you will need a longer rest time (3 to 5 minutes) to restore your energy supplies between sets.

A superset is when you work on different muscle groups with very little or no rest time in between.

"Supersets are a great bang-for-the-buck training principle that allows you to perform an increased amount of work — in this case sets and reps — in a given amount of time," Wickham says. "You will be able to perform more reps and more sets in the same amount versus the standard one- to three-minute rest periods between your sets."

For example, you can do 12 reps of a chest exercise and move immediately into 12 reps of a back exercise. "You can work on opposing body parts in back-to-back sets — or you can work the same area of the body for both sets to work that muscle to absolute fatigue."

Supersets are a great technique if your goal is fat loss and muscle building, according to ACE.

Instead of taking your exercise through the full range of motion, another way to challenge your muscles is to stop mid-range for small pulses or an isometric hold (more on these below). These partial-range exercises are a great way to fatigue muscles quickly to build endurance and strength.

"For example, you will perform as many full range of motion reps as possible in your set, and then perform two to five more partial-range-of-motion reps at the very end," Wickham says.

This may look like: doing several full squats followed by several mini-squats or pulse squats at mid-range.

For isometric holds, instead of pulsing, you are holding the muscle still against resistance. For a squat, this would look like pausing once your thighs are parallel to the floor (or as close to parallel as you can get) and holding for 1 to 2 seconds before standing up, according to the NASM.

Instead of working both sides of your body at the same time, mix it up by working one side at a time.

"Unilateral exercises allow you to work on a single arm or leg at once. This allows you to test if one limb is stronger than the other, as well as working on your strength of each limb individually," Wickham says.

When it comes to leg-focused unilateral exercises, specifically, you also get an added bonus of challenging your balance, according to Wickham. For example, try a one-legged squat or one-legged calf raise without holding on to anything to work on your balance, strength and proprioception (body awareness).

"If you are used to performing all of your exercises with both arms or legs, performing them individually can be a big challenge," Wickham says.

Incorporating cardio in between your sets is a great way to get your heart rate up, which increases endurance and burns fat.

"Adding in bursts of cardio between sets can increase the difficulty of your workout," Wickham says. "If someone is going to add in cardio, I typically suggest short, intense bursts, like 10 to 30 seconds worth of work in the form of burpees, the owing machine or sprints. This would come in the form of a circuit-style HIIT workout."

Turning your normal strength routine into a HIIT routine gives you the benefits of a cardio plus muscle building in a shorter amount of time.

"Compound exercises are very effective at working multiple joints and areas of the body at the same time," Wickham says. Examples of compound exercises are bench presses, deadlifts, squats, shoulder presses and pull-ups.

You can also add in a combo move. Instead of just doing a biceps curl, for example, you add another element to work several muscle groups, like doing a lunge while doing the biceps curl. If you are working your upper body, look for ways to add in a lower-body component, and vice versa.

"The more joints you work during the same exercise, the more muscles have to be recruited in order to perform the exercise. This will lead to greater increase in strength and hypertrophy versus performing single-joint isolation exercises like a biceps curl or leg extension," Wickham says.