It is still a commonly held belief among many that abdominal isolation exercises are the key to achieving abs. Look at any ten-minute ab infomercial and they’ll confirm it, promising swift results to boot. This claim is what is commonly known as “targeted energy expenditure” and it is unequivocally false, scientifically disproven since the 80s.
The body holds adipose (fat tissue) in specific areas, most commonly the lower abdomen and gluteal regions. Whenever energy is required and not being sufficiently provided by more immediate glucose stores, that fat tissue is broken back down into lipids and sent through the bloodstream to the cells that need it, wherever that may be in the body. Using muscles physically close to where the fat stores are located will not activate or increase the usage rate of those fat cells any more than any other muscles in the body.
Making your abs visible is a result of being at a sufficiently low body fat percentage (around fifteen percent to start to see them), which is by and large due to diet. If you want visible abs and can’t see them right now, consume fewer calories than you use for long enough to lose the necessary adipose tissue. Eating whole foods; meat, fruit, nuts, and seeds with minimally processed goods (bread, dessert, etc.) is a solid rough guideline. In terms of training, focus on keeping your heart rate high and choose movements that utilize multiple muscle groups (squat, deadlift, pull-ups, etc.).
These demand more energy on average and thus use more fat stores than isolation movements. Hypertrophy training (increasing muscle size) also has the dual benefit of increased muscle mass, requiring more energy to use and maintain, and thus further upping energy expenditure
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