Rest Intervals

Contributed by: Shellie Billingsley, NASM-CPT

When people hear the term “personal trainer,” they may imagine a loud drill sergeant yelling at them while they’re doing push-ups. While encouragement and motivation are important qualities of a personal trainer, it is also necessary for a trainer to tell their client when to rest throughout their workout. In order to exercise efficiently and safely, it’s good to know what a rest interval is, why it is important, and how to apply it to your program.

A rest interval is the amount of time taken to recover in between exercises. When lifting weights or using other forms of resistance (such as body weight, cables, machines, etc.), there’s always a point when you stop and take time before repeating the same exercise, or moving on to a different one. You may be thinking, “Duh!” but you may not understand why that rest interval is so beneficial.

One of our body’s primary sources of immediate energy is known as adenosine triphosphate (ATP). In simple terms, ATP is an energy-carrying molecule within our cells that is required for mechanical work, like exercise. The amount of time you take to rest during your workout will determine how much ATP, or immediate energy you recover. This is important because not getting enough rest time can lead to fatigue, decreased neuromuscular control, and could ultimately result in injury. On the other hand, too much rest time can interfere with personal goals and can lead to an unproductive workout.

“Too short” or “too long” of a rest time heavily depends on the type of workout you’re going for. It takes approximately 20 seconds to recover 50% of ATP energy, 40 seconds to recover 75%, one minute to recover 85%, and three minutes to fully replenish your immediate energy stores. So if you are using lighter weight and want to build more endurance, aim for shorter rest periods. When lifting heavy and looking to increase overall strength or muscle mass, longer rest times are crucial.

Ultimately, several other factors come into play when working towards a specific goal such as repetition, sets, duration and exercise selection, but rest time is easy to overlook. Many believe they must feel completely defeated at the end of a workout in order for it to be a good one, and others may linger around an exercise facility and not use their time efficiently. Talk to a health and fitness professional to fully understand how to structure your workouts for maximum gains towards your goals.

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