Rectus abdominis, informally known as the abs muscle, is a long muscle of the anterior abdominal wall. In those with low body fat, it is clearly visible beneath the skin forming the 'six pack'.

In fact, for some individuals, a pursuit of six-pack abs may indicate an unhealthy relationship with food or an overly restrictive diet. It's more valuable to focus on overall strength, endurance, flexibility, and cardiovascular fitness, rather than fixating solely on the appearance of a toned midsection.

This number is determined by genetics. Around 60% of the population is born with three tendinous intersections, which means most people would sport six-pack abs if they worked at it, according to multiple studies. Approximately 20% instead have four of these intersections, which make up eight distinctive abs.