Celebrity trainer Gunnar Peterson shares how to right the fitness wrongs he sees most often.

• Quickly cranking out crunches

Take five seconds to lift and five to lower. A slow as molasses pace forces your abs to contract longer which means they work harder.

• Thinking cardio is the only way to blast calories.

Lifting weights torches 200 in just half an hour. If you never strength-trained before, try out a group fitness class that uses dumbells or weighted bars to help ease you into it.

• Going to the gym without a plan.

Do that and you’re likely to default to your standby routine. This will sabotage your progress. Instead, take a few minutes to organize your session and try to work in something new.