The ronaldo's KNUCKLE BALL
There are a few things that play a very vital role in Ronaldo’s successful freekicks. There’s the usual talent, skill, short back lift, power and so on. But there is that one special attribute that counts above all these factors. And that is hard work.
Most players have the technique but lack the shot power and some have the shot power but cannot implement the technique in its entirety - but Ronaldo could do both.Now, knuckle-ball is when you kick the ball right on the valve (the place from where you inflate a football) - and why it produces so much swerve.
The one against Portsmouth and Arsenal really stand out and can never be replicated in world football at such a platform.
source