How can it be a 'competing motor pattern' when squatting has absolutely nothing to do with sprinting. If you go out and run lap after lap and do a lot of middle distance and long distance running/specific training for those events than I could see speed suffering- Speed will suffer because your body is compensating for endurance. However, I just can't see how going to the gym and doing a few sets of squats a week is going to affect, let alone deteriorate your speed.
I agree that the term 'competing motor pattern' makes it sound like BS but I'm still believe that Avishek's experience isn't totally unheard of.... even if I think his interpretation of it is a little off. A few points to remember:
1) He doesn't sprint very much. All my experience with squatting + sprinting is with sprinters who already sprint a lot more than him. On average we are talking about being on the track 5-6 days a week and doing about 500-1000m of speed work, another 2000 of special endurance work, and probably 5000m of tempo running per week. Not to mention warm-up, bounding, drills, exchange practice, sled pulls, block work, etc, etc. The point is there we are talking about sprinters with very very well reinforced motor patterns for sprinting.... When we add squats twice a week in this case, there seems to be no detriment aside from fatigue. I don't know if his competing motor pattern concept is true, but it could be true but only observed for an athlete like Avishek. Most people either spend more time on the track or are relative beginners when it comes to strength/speed training and so wouldn't notice it.
2) He also doesn't squat very much. Relatively. This is important because while he claims it has nothing to do with fatigue it's really subjective.... It surely isn't explicit fatigue but if his recovery from squats is not great.... he might have residual fatigue 3-5 days after moving big weight in the squat... What would be interesting would be finding someone who is well adapted to daily squatting (like an oly lifter) and to being training them in the sprints. Then after some point drop the squatting and see if/how much performance increases.
I think the bottom line is that sprinting at high speed involves hip hyperextension; something not very well trained in the weight room. Maybe that training hip extension in a ROM shorter than what is necessary for sprinting will cause the athlete to run slower?
I think Avishek's point can be true without necessarily indicating that he shouldn't squat. Perhaps at his current strength/speed levels squatting is very detrimental to speed. Maybe he gets faster and his missing link is a lack of isometric quadricep strength or his block work is holding him back and he will venture back into the squat rack and add some strength.... But sprinting is really a biomechanically complicated movement that the "key" isn't the same for everyone. It's not like that pedestrian activity of double leg jumping practiced by everyone on the board.... Sprinting is much more sophisticated.