Successful performance in a long and challenging event like a half-Ironman requires many months of diligent preparation off a substantial fitness base.
Following is a general overview of a sensible training program that will lead you to peak performance on race day.
Spring Training Program
Here, the difficulty begins to escalate as you leverage the work of your initial base period (December and January) and start to develop the specific fitness required to race long-distance triathlons.
Note that the primary emphasis is still on aerobic heart rates, for this is where the most significant gains can be made in race performances.
Many triathletes make the serious mistake of hammering too many high-intensity workouts. These workouts are fun and provide instant gratification, but they come at a great cost of energy.
If your goals are Olympic distance, half-Ironman, and full Ironman, and you are below world-caliber performance level, you can improve by leaps and bounds by improving aerobic function.
Conversely, anaerobic workouts will generate minimal improvement unless you have a strong base (built earlier in the winter). Even then, the analogy fits that you can either "fine tune a Volkswagen" (high-intensity training) or "build a Ferrari" (focus on aerobic development).
With a strong base developed, you can begin to introduce some race-specific training, such as long time trials on the bicycle or half-marathon running races.
Preparing for Peak Performance
When it is time to introduce intense training to prepare for peak performance, careful guidelines must be followed. Intense anaerobic workouts can deliver excellent performance benefits when they are conducted in the right manner.
On the flip side of these outstanding benefits comes a high risk of burnout, fatigue and injury. Overdoing the hard workouts can easily result in you leaving your best race out on the training roads.
Following are my Four Rules of Intensity for anaerobic workouts. Observing these guidelines will enable you to properly absorb and benefit from your hard sessions:
Rule #1: Always build an aerobic base before introducing anaerobic workouts. The best way to determine that you have indeed built a strong base is steady improvement in MAF test results and generally feeling strong and energized from your training.
Rule #2: Always be 100 percent physically energized and mentally refreshed when you conduct an anaerobic workout. Never force your body to do intense exercise when your spirit is not willing.
Rule #3: Never conduct anaerobic exercise for more than six weeks without a break. Benefits will dwindle the longer you exercise intensely without a break. This is true even if you are observing rule #4 and limiting frequency of anaerobic workouts in your schedule.
Rule #4: Limit anaerobic exercise to 10 percent of total weekly exercise time. Even during anaerobic training periods, time spent at high heart rates is only a fraction of total weekly exercise time.
After six weeks of anaerobic exercise, you should introduce a micro-rest period of at least two weeks. During this period, you should cut back on workout time and frequency by at least 50 percent to ensure that you are totally rested when you resume training.
During your anaerobic phase, total volume of training should drop sharply (at least 33 percent), and your basic standard fitness maintenance workout should drop too. For example, if your standard swim workout is 3,500 meters, drop down to 2,500 to 3,000 during the anaerobic phase. If your standard run is one hour, cut it back to 40 minutes.