Not many athletes are in the fortunate position of world class athletes in well funded sports where a therapist is available prior to each event. More likely is being a in position to arrange for a preparatory treatment one or two days before the event, with time for a warm up and stretch on the day.
If considering a pre-event massage, we suggest that it is worth having a trial run before a serious event (perhaps at a training weekend, for instance) to ensure you understand how you and your body will respond to the treatment.
Once comfortable, then book your treatment for a day or two before your event. Make sure you explain to your therapist what you are looking for to ensure they don’t overwork areas. Even a day or two before the event, a pre-event massage should help prepare muscles for the demands to be placed upon them.
Where a treatment is available on the day of the event, typically within a half hour of the event, then a therapist would normally focus on stimulating the musculature and increasing blood supply. They would not normally attempt to treat injuries or work too deeply into adhesions and tightness.