Messaging your coach
Messages opens from the bubble in the Today header. It's an inbox of coach conversations. Each coach has one thread. Each thread shows a context line that names the program or team it came from. A note under the list states the rule: coaches you train under can send you messages here. Athletes can't send messages to each other.

How a conversation starts
Your coach starts it. Athletes can't start a new thread. When a coach sends you a message, the conversation appears in your inbox. From then on you can reply freely. Until then, the inbox shows a "Who can reach you" list: coaches on your teams, and coaches whose programs you run.
This is by design, not a missing button. The messaging surface exists for coaching: a coach checks in, adjusts the week, or answers a question they invited. The coach decides when to open that channel. If there's no thread from your coach yet, there's nothing to fix on your end.
Replying and attaching sessions
Open a thread. Reply as you would in any messaging app. The one training-specific tool is the session receipt. A receipt is a completed session from your Activity log, with its sets and loads. When a coach asks "how did Tuesday go?", the receipt is the answer. It shows exactly what you logged, not a summary from memory.
You can also share a receipt into a coach conversation directly from the finished session itself, without opening Messages first.
Managing the inbox
- Remove a conversation from the inbox if you're done with it. This tidies your list. It doesn't block the coach. The thread returns if they send another message.
- Report a conversation if something in it crosses a line. Reports go to the platform for review.
What your coach sees
If you're on a coach's roster, they already see your logged training history. That's the coaching relationship working as intended. Messages add conversation on top of that visibility, not the visibility itself.