Great at first 4 or 5 holes and last 4 or 5....TERRIBLE in the middle

I have been working on my mental approach to the game and I can already see improvement. One issue that I am still having trouble with is my focus in the middle of a round. Here are some recent rounds and stats on the BEG/END holes and Middle holes. The par 5s and 3s are pretty evenly dispersed in these examples.

103-44 on 1-4,15-18/59 in middle

106-47 on 1-6, 16-18/59 in middle

54 on 9 holes-25 on 1-3,8-9/29 on 4-7 (that one less hole!)

Clearly I start off well, and when I know the round is almost over I play well. Does anyone have any advice/theories/similar experience that they could share?

The distribution of scores doesn't determine your handicap, the total does. We all want to think we're as good as our best holes/shots, but this game is about the full holes, entire rounds, 4 day tournaments, and period from which our handicap is calculated. The mistakes are a big part of everyone's game so you can't simply disregard them. The fact that there's a big difference between the best and worst holes just shows you are inconsistent, not that you are better than the score indicates.

I'm not trying to say that I'm better than the score. I'm fully aware that at this point my score will improve more by trying to eliminate mistakes instead of trying to par more holes. I was asking for any advice because there seems to be a pattern to my inconsistency.

Really have no idea because I know nothing about your game or your mindset but here's a wild guess in a nutshell. First part: Happy to get the ball in the fairway and on the green without looking bad. Middle: Feeling pretty good, getting loosened up, and also a little loose with mechanics, and a little wild. Start overdoing everything that felt like it was working. After all we all know if that slightly closed or slightly open stance (or anything like that) worked so well on the last hole we'll go way more and that ought to work EXTRA well. (Not). ;-) Last part: Realize you (like most of us) aren't good enough to be long, loose, or wild and start playing golf again. ;-)

It has to with your ability to concentrate. You can maintain your concentration for about an hour, then it goes away. This pattern also shows that it takes you a long time to get it back, too.  Why your periods of concentration occur only at the start an the end of the round is up to you to examine, but that's the basic reason.

Makes total sense Rec golfer. I'm stressing too much trying to break 100. I think when I have lapses of concentration and hit shitty shots I blow up and it carries over to the next few holes. After I accept that Im not gonn break 100 I relax, accept it and bogey my way home.

Hello, I've been playing golf with this mindset and it has produced some pretty good rounds for me. Most recent round was an 80. While playing I have 18 holes to battle. 18 separate holes. I need full dedication on every shot, every hole, to post a good overall score. If I think about my total score I'm losing focus. I use an app to post my score on each hole. After I post it I start thinking about my next tee shot. After #1 is posted, it's gone from memory. I now have to think about #2 and I've got 17 left to give my best effort. Don't dwell on a bad shot or a 3 putt. It's going to happen. Tell yourself you are better than that and move on. Focus on what each shot is giving you. Wind, lie, angle, staying out of OB, etc. After about 4 or 5 holes it is mentally exhausting to maintain a high level of focus. You have to just keep telling yourself to stay focused on each shot. Golf requires a lot of practice. It has for me anyways. I practice 2-3 days a week and play once.