12.8mm=1.28cm (Average fingernail length)
73px=1.28 cm
1px=0.01753424657 cm
645px= 11.3095890376 cm
1166px= 20.4449315006 cm
1166-645 = distance hand move =521 px
521px= 9.13534246297 cm
Manabu's hand moved 9.13534246297cm or 0.0913534246297 meters
I use peak athletic human speed for Manabu which is 10.03m/s (Reasoning for this is that Manabu is a 5th dan in Karate and 4th dan in Aikido, dan being master ranks. He was relative to Ayanokoji in their race, He was able to block Ryueen's punch despite his vision being obstructed by the snow Ryueen threw and its stated that he is second to none in ANHS in terms of learning abilities and physical conditions) (This was stated by one of the Teachers so it wouldn't include characters such as Ayanokoji or Koenji as neither of them have outwardly showed any feats that would put them over Manabu in the teachers eyes)
0.0913534246297/10.03 =0.0091080184
The Timeframe is 0.0091080184 seconds (Here the scan that shows Ayanokoji only moved once Manabu attacked forward)
Manabu px height is 362 pixel the panel is 1076px (Manabu real height is 178cm/1.78m)
2atan(tan(35deg)(object size in pixels/panel height in pixels)) (Formula used)
2atan(tan(35deg)(362/1076))
0.462707307 rad =26.5111758410299 degrees
Distance = 3.778 meters
Speed is 414.799m/s = 415m.s
(Supersonic)
The pictures are in the forms of links