Athlete is training too slow

Get a professional lactate test and then use a heart rate monitor. Ignore the paces it’s summer for goodness sakes.

Scale back his mileage and let him slow down. Right now he's not handling the new mileage well. That could be from heat like you said or it could be that he needed to get there more patiently. This early in the summer you'd like to think it isn't overtraining, but whether that's the cause or just what it looks like the treatment is the same.

I wouldn't worry too much about how fast his mileage is. I have a girl (I don't mean this to condescend) with almost identical PRs and she runs mileage slower pretty often. I used to get hung up on it but it works for her.

Program a few extra days off the next week and let him run shorter and easier. Wait for some feedback that he feels "fresh". Even just a day where he can do 3 miles and have fun with some strides with long rest can help to feel better

Where do I get a professional lactate test? Seems aggressive for a junior in hs, no?

Why are you timing kids in mid summer? Let him run comfortably and get the distance in.

Get a professional lactate test and then use a heart rate monitor.[ DONT]

Ignore the paces it’s summer for goodness sakes. [its Sumer for fookssakes]

A lactate test at this point is major overkill.

As several have said, it's summer. And on top of that, it's early summer. And it's hot. Don't worry about his paces now, as long as he's getting his mileage in.

But ask him how he's feeling. Get some feedback over a week or so. If he's struggling, then an iron test might be worth doing. Also talk to him about his diet, especially if you think he's too thin.

I don't think I'd want you as my coach. You don't sound like you know what you're doing.

Running slowly on easy days should be encouraged, not fretted over.

Also, you shouldn't have target times for tempo runs; they should be done to HR (or barring that - perceived effort).

Thankfully my coach never had a stopwatch on me during the summer. I turned out alright. Just run baby.

Get a blood test and check serum ferritin levels.

He doesn't have enough experience to run precise pace/times in training at this stage in his development without other runners around him or a pacer. You do realise its difficult for even elite professional athletes to run to a pace in races - thats why they have pacemakers.

You're putting him under too much pressure to make precise times. What matters is how he races. He might need a few years to build up if he hasn't had a junior running career. Make it fun.

He's also tall for a track athlete.

Its very sad to read a coach putting an athlete under so much pressure to make specific times in training when he is only 10s or so off.

If all he's ever run is 30 mpw, doesn't it seem a little aggressive to bump him up to 40 mpw three weeks into summer training?

I already upvoted the other guy who said this, but if he’s fading inexplicably in summer heat, that’s often an indicator of iron issues. A full iron panel is like 30 bucks and iron deficiency is extremely common among hs kids. More so with girls than boys but like 1 in 10 w/ boys, too.

Easy to run 7- 7:30 with the team and problem run 8:30-8:45 and sometimes 9:00+ ? Must be related to poor heat resistance or lack of any substance in the body. Sounds like most truly heatrelated.

Come on People--this dude is 6-2 and 140 lbs. An absolute stick. Get his iron, ferritin, b12, etc. levels tested. Then make sure he is eating enough; He's a high school kid with likely a rocket metabolism.

If his pace has fallen off a cliff, this is the first place to look.

I think you answered your own question. Heat and humidity doesn’t affect everyone the same. Poor mans altitude! Maybe his routes are hillier? Summer running should be a lot by feel especially with the heat and humidity. Make sure his paces are based on current ability. Make sure he is hydrating properly as well. He is running more and for some it takes time to adjust.

Proceeds to suggest the least reliable and most trailing indicator for monitoring threshold efforts…

You’re three weeks in, it’s hot, he’s young. Iron panel, diet and letting him adapt to additional volume are all good moves.

This is one of those instances where "just run baby" is the appropriate answer.

First tell him to increase his calorie intake. Second, don't give him times to shoot for. Training age seems pretty young. Just have him do half mile loop or something around that distance and tell him to run controlled and try to increase pace a little for each loop. Keep it simple.