A six-pack is something that most every athlete wants- for various reasons. Most people think that if you have a six-pack, it means you have a strong core. But that necessarily is not the case.
Everyone has ab muscles. Having a six pack only means you have a low body fat percentage, which allows those muscles to show. IT MEANS NOTHING ELSE.
So is a six-pack what you as a soccer player need to excel on the field? Not necessarily. What you actually need is a strong core. A strong core will allow you to remain stable and transfer force from one body part to another. This will allow your body to move as efficiently and effectively as possible.
Every soccer player should be doing tons of compound movements in the gym, along with core stability exercises. If you’re doing all of that AND you have a six-pack, good for you! But if you don’t- no worries, you’re still doing what you need to do to have a strong core- which is what really counts.
Summary: Having a six-pack is nice and all, but what you need is a strong core.