Split Decisions

Any sport · Tested in public on an Ironman

Use AI to coach yourself at the sport you want to get better at.

Running, cycling, swimming, triathlon, golf, or anything else with a goal you can measure. These are the prompts and setup I use with Claude, free to copy. I'm the test case: after missing sub-5 at 70.3 Michigan, I'm letting Claude coach me to a rematch and then my first Ironman, misses included.

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James smiling as he runs down the finish chute at Ironman 70.3 Michigan, bib 2073
70.3 Michigan · Bib 2073Goal 4:59:59
Swim
0:30:26
7th in division
T1
0:09:04
calf cramps
Bike
2:45:40
36th
T2
0:04:18
Run
1:53:28
46th
Finish5:22:56+22:57

The test case: me

Where my 23 minutes went

The first thing I asked Claude was where my race went wrong. I was 7th in my division out of the water and finished 46th. All of the time was lost on land.

  1. Bike−10:00Dropped chain on the first climb, then a cramping last quarter
  2. Run−7:00Stops at mile 4 (cramps) and mile 9
  3. Transitions−6:00Calf cramps stripping the wetsuit in T1

The debrief prompt I used, which works for a round of golf or a 10K just as well.

The starter kit

4 prompts · free · any sport

01 · Once

Your athlete profile

You are my coach for [sport or activity]. Base every plan and change on my actual data…

02 · After a race

Performance debrief

Here's my data from [race, round, match, or test]. My goal was [goal] and my result was…

03 · At the start of a season or a new goal

Training plan outline

Using my profile and history, propose when my next training block should start and lay…

04 · Every week

Weekly check-in

Here's my week: [planned vs done, how I felt 1-10, sleep, anything that hurt, any…