Soto uke (middle level block) has many applications
Within karate blocks & the blocking movement you might find afew more techiques than just the bottom line block you think you are performing.
"Always be ready to release your mind." Gichin Funakoshi
This is true of all karate blocks, here are my thoughts on one of those blocks, sote uke (middle level block).
The pristine version performed by raising the right hand and bending the elbow with the knuckle of the right hand thumb touching the top of your right ear, the left hand is extended out directly in front of you. Then you withdraw the left hand to the hip and arc your right hand around to stop the middle level punch or strike (usually a linear/straight attack).
There are many different types of applications for the sote uke, one application could be,
First half of the movement
Block/cover response to a left hand round punch by raising your right hand (alittle closer to your head than whats shown in the photo (only one i could find)) then use your left hand to strike or grab, a good way to look at it is block/cover/shield a left hand round punch to your head with your right hand and left jab simultaneously OR with your left hand grab the assailent (see second half).
Second half of the movement
With your left hand (which is outstrechted) grab his clothing, hair ear, behind the neck and pull him in towards you and hammer strike with soto uke, to chin, temple or side of face/head/neck.
Ofcourse this could apply to both sides of the body, that is if it was a right hand round punch use your left hand to block/cover and your righthand to strike, these teccniques utilize gross motor skills which under adrenal like conditions (real fight) will be easier to execute.
And when you do use them as pure blocks they are of the shortened variety that is there is no chambering or withdrawal of the non strking hand to the hip, as Lyoto Machida shows us below with the (osae uke) pressing block no wind up no retracting the other hand just perfect timing and execution.
Osae uke jodan seiken gyaku zuki
Lyoto Machda shotokan karateka in UFC
JKA shotokan karate competition same technique Osae uke jodan seiken gyaku zuki
Some more applications of karate blocks.
Utilising Basics-1 Sensei Sam Walker shows applications of basic blocks
Utilising Basics-2 Sensei Sam Walker shows applications of basic blocks
gedan barai variants by Garry
Upper block variants by Garry
chudan block variants by Garry