Does anyone else get a weird vibe from that deleted Instagram post? It reads like something someone else would post using the cheating runner's credentials to out her, not a personal apology and admission of cheating.
The overall wording and use of all-caps in some places is also pretty weird.
The vibe I get is anguish, shame, and regret as someone is trying desperately to salvage their reputation and finding that they can't. I can definitely picture someone writing that; if it was forged (which I have no reason to believe) it felt convincing to me.