However, workout strategy aside, sometimes you only have time for one workout at a time. The best strategy for scheduling workouts within a day is to first consider your personal schedule, then consider which workout needs your physical and mental best. Schedule the day accordingly.
A happy athlete that can consistently accomplish workouts is faster than an unhappy one that often misses workouts. It is best to do workouts when they fit your lifestyle and cause you minimal life and family stress.
I noticed on your long-distance training plans that the long run and the long bike ride are planned for the weekend. My work schedule has me working on one day of the weekend, and I don't have two days off in a row. Does splitting the long workouts make the training plan ineffective?
First let me address a question you didn't ask, and that is "Should I do the long run or the long bike on the first day?"
In general, for new athletes and those prone to running injuries (those with glass legs), I put the run first. My logic is that it's preferable to do a long run on fresh legs when your form will be at its best. Do the long bike ride on the second day when your legs will be tired, but injury risk is minimal.
More: Dealing With an Injury
For those looking to adapt to running on tired legs, I will put the long bike ride first and the long run on the second day.
I schedule the long workouts back-to-back because I believe there are endurance benefits to be gained from two long workouts done within 24 hours of each other. Think of it as one giant workout with a very long rest interval between efforts.
That written, I've had a good number of athletes separate the long workouts by 24 to 48 hours due to work schedule, recovery or injury issues (they needed more rest between long workouts to stay healthy) and do just fine on race day. The training plan was still very effective.
More: 10 Steps to Designing a Training Plan
One of the huge benefits of the plans on Active Trainer is that you can move pre-planned workouts around to better fit your personal schedule. If the plan shows swimming on Monday, Wednesday and Friday, but you want to swim on Tuesday, Thursday and Saturday, the workouts can easily be shifted.
What is best for you?
When you have your training plan in front of you, take the time to figure out how to organize and plan your day and week to accomplish work, social activities (family and friends) and training for a triathlon. Balancing your life helps to minimize stress and promotes health. In the end, isn't better health the ultimate goal?
