My training would always consist of a mixture of short - medium - long runs with a weekly session of fast sprints usually on the short run and usually on a large hill. This helps to build strength and endurance. In addition I would usually go the gym twice per week to strengthen core body as this helps to build strength and endurance. Cycling is mainly about time in the saddle and hill endurance.
A key aspect of building strength is resting in between to allow your body to recover ready of the next training day. So it is vital that you build in an easy week once a month and allow some rest.
To test progress we will complete 2 trial sessions in each discipline. This will include a 3 day session of 20 miles run and 45 miles bike each day. Kayak will include a 25 mile kayak on a lake or sea.