The squat is the best exercise for building muscle, according to world champion powerlifter Blaine Sumner

• Squats are the best exercise for building muscle, world champion powerlifter Blaine Sumner told Insider.
• They're compound movements that engage multiple muscle groups.
• Sumner strength trains six days a week, resting for up to seven minutes between sets.

Squats are the best exercise for building muscle, according to world champion powerlifter Blaine Sumner.

Sumner, who is 6'3" and weighs 400 lbs, holds multiple powerlifting world records and can squat 1,135 lbs.

He told Insider the squat is "without a doubt" the best movement for building muscle overall because it engages so many muscles in the body.

Squats are 'the king of exercises'

Squats are compound movements, which means they work multiple muscle groups.

"Its nickname is the king of exercises," Sumner said.

Five times Fittest Man on Earth Mat Fraser considers squats the best exercise for improving fitness, and UK's Fittest Man and personal trainer Zack George also rates the exercise as one of the top five muscle-builders.

"If someone's a powerlifter, they should practice the back squat," Sumner said. "But if someone's looking to build muscle or just become a better athlete, front squats and all kinds of variations of squats are equally as good."

Front squats mean holding a barbell across the front of the shoulders under the neck, and in back squats the bar is positioned at the top of the back.

Back squats are one of three lifts in powerlifting competitions, alongside the bench press and deadlifts. These are also compound movements and what Sumner recommends for building muscle after squats.

Squats can also be performed holding a dumbbell or kettlebell in front of your chest (goblet squats), holding dumbbells on your shoulders, holding a weight with arms stretched overhead, or just with bodyweight, for example.

Sumner rests for up to 7 minutes between sets

Sumner trains five to six times a week for three hours at a time, and each session focuses on one or two particular lifts. 

"Two days a week I'll focus on squats and deadlifts, two days are bench press, and the other two days are more accessory-type movements," he said. Accessory movements are isolation exercises such as bicep curls.

Sumner recommends non-athletes structure their workout like this: a warm up, followed by compound movements, then accessory movements.

"While you're prioritizing compound exercises, you want to take as much rest as required between sets so that you're fully recovered for your next heavy set, because otherwise you can get injured relatively easily," he said.

Sumner trains for strength, meaning heavy weights, low reps, and long rests between sets — he rests for up to seven minutes if he needs to.

"If someone's just looking to build muscle or doing more bodybuilding-type training, it's OK to cut down on rest, but for trying to lift the most weight that you can, you definitely need to take sufficient rest," Sumner said.

For accessory movements, you don't need to rest as long because they're less intense, he said.

Don't take shortcuts

Sumner believes many people make the mistake of looking for shortcuts when it comes to building muscle and strength, when really you need consistency and patience.

For this reason, it's important to learn to enjoy the process, he said.

Sumner thinks of training, nutrition, and recovery as the three legs of a stool — they need to be prioritized equally for the stool to stay upright.

"Everyone thinks about building muscle and strength in the gym, but actually you're tearing yourself down in the gym and you need to build yourself up outside of the gym through proper nutrition and recovery," he said.

Sumner has an unconventional approach to nutrition, consuming 8,000 calories per day in the form of meat shakes: boiled chicken breasts blended with sweet potato or rice, almonds or olive oil, spinach, and water.