Does Travel Speed Relate to Combat Speed?

If I apply logics to this matter:

If I can travel a at light speed because I can move at light speed this means I can also move my limbs at light speed (combat). Now do the calculations, if I punched somebody with my arm moving at light speed or faster it would release so much energy it would create an explosion similar to an atomic bomb.
Now imagine Jackie Chan raining blows impacting with the force of atomic bombs.  

Any movement at light speed is silly because it screws so much with reality, but if I can do combat at light speed things really escalate.

Objects with mass can't move at the speed of light or beyond. The faster you go, the slower you will start to go. Physical mass will slow you down, light doesn't have mass.

Isn't this a question of acceleration? Sure, you can travel at light speed but how long does it take you to get there? Combat usually is about shorter movements and quick changes in direction, so being able to ultimately achieve light speed (or any other very high speed that would improve kinetic impact of whatever weapon you are swinging) will not really help you if acceleration time is too long to get there in a combat situation.

Let's look at another Example like the Expanse: You could in principle use an unmanned ship with a Epstein drive as a kinetic weapon. This would work splendedly against a target that is either stationary in reference to your starting point or has a predictable pattern of movement (such as an orbit) so you can calculate it's position at the time your weapon will hit the target. However, as soon as you are dealing with a moving target (as is usually the case during a combat situation), you'r kinetic impactor will basically be useless because it's power of thrust would not be enough to perform the encessary course correction on the way.

Therefore travel speed does not necessarily equal combat speed or performance.

I just slapped you all in the face and kicked you all in the bums and you never knew it because I move at the speed of light. You may have noticed a slight blur.