My thoughts ....
a) I reckon you lose your audience in the first minute. Talking about how carbonic acid breaks down is dull as ditchwater. Totally unnecessary as you go on say.
b) It starts being interesting when you show the graph circa 1min30-45. So where you run out of time at 4min40 ... you really only have a 3-min video so far.
c) It's not lactic acid, it's lactate. This is basics - you should be teaching your team the correct terms.
d) Adding the blue Duration line to first graph distracted me. I found myself trying to think what a blue line going gradually downwards meant. To me, it's simply that as running speed increases, lactate increases and that stops you running for long at fast speeds.
e) You could replace blue line by relating the thresholds / speeds to typical race distances to highlight durations. e,g, LTP1 is marathon for elites, 1/2M just below LTP, 10K above etc.
f) But really all team need to understand is that as lactate rises, you can't run for as long at high speeds. and therefore training is done to slow production by training to push LTP1 up, clear more lactate through shuttle in between LTP 1&2, tolerate/buffer more above LTP2.
g) I like that you're trying to keep them short.
h) you sound confident and come across as well.