This is an excerpt from Triathlon Science by Joe Friel & Jim Vance.
Combination workouts bring two or more disciplines into a single workout, either for convenience or for specific race preparation. The most common combination workouts are swim to bike, bike to run (usually called a brick), and run to bike, depending on the goals of the triathlete and time of year.
A small segment of the triathlon population experiences some lightheadedness when transitioning from the prone position of swimming to the standing position of running, as triathletes do when moving from the swim to the first transition. Another small segment of the triathlon population experiences unusual leg fatigue going from swimming to running and then cycling.For these triathletes, one strategy is to set up a bike on a trainer on the pool deck.
Triathletes can begin with an easy swim of 500 meters or so and then transition to the trainer for an easy spin of around 10 minutes. They repeat this sequence two to four times in a single workout.
If the triathlete is not adapting or feels so lightheaded that passing out is a possibility, a doctor should be consulted to be certain that no medical issues are present. Depending on the severity of the problem, triathletes may want to be checked out before doing any swim-to-bike workouts.
As triathletes adapt to the easy swim-to-bike workouts on the pool deck, they should increase intensity by following a fast swim segment with an easy ride. The second round should be an easy swim followed by a faster ride. As adaptation to the transition between swimming and cycling continues, the triathlete can increase the intensity of both the swim and the ride.
Many triathletes do swim-to-bike workouts as a matter of convenience, particularly on weekends. Many do a pool workout and then head straight to a bike workout. With workouts sequenced in this manner, they can decide which workout or workouts should include intensity. As triathletes approach race day, they may want a swim-to-bike workout as a dress rehearsal for race day.
Swim-to-bike and run-to-bike workouts are often called combination, or combo, workouts. The bike-to-run workout is often called a brick. Although the history of the word is not clear, one theory is that the name was given to the workout because when triathletes go from fast cycling to running, their legs feel like bricks.
To help triathletes adapt to the change of body movement and muscle recruitment from cycling to running, and the feeling that this change produces, aerobic brick workouts are a good place to start. Some prefer to do brick workouts every week throughout the training plan, but others limit brick workouts to once per month, perhaps as a workout during a recovery week. Others limit brick workouts to certain macrocycles. No standard has been set about how often to perform brick workouts, and some triathletes appear to make this adaptation better than others do.
In one study on elite international Olympic-distance racers, the intensity of cycling did not have an adverse effect on neuromuscular control and running economy. Even moderately trained triathletes experienced little influence on running muscle recruitment after cycling. These studies may lead the reader to believe that experience in the sport of triathlon eliminates any effect of cycling on running economy and muscle recruitment, but that is not true. A third study found that despite years of training, some elite triathletes do experience changes in leg movement and muscle recruitment in running after cycling. The effects of cycling on neuromuscular control and running economy appear to vary among people.
When deciding how many bricks to include in a program, triathletes should consider their experience level, goal race distance, and race results. Slower sprint- and Olympic-distance racers are more likely to do short brick workouts. For faster sprint- and Olympic-distance racers, brick workouts are often in the range of 50 to 100 percent of race distance. For half-Ironman racers, bricks are often 25 to 50 percent of race distance. For Ironman racers, bricks become less important because the need for blazing fast transitions is not an issue except for the top triathletes.
For Ironman racers, the benefit-to-risk considerations of long brick workouts need to be evaluated. For example, how much value is gained from doing a 60-mile (100 km) bike ride followed by a 10- to 13-mile (16 to 20 km) run? Would this triathlete be better served by entering a half-Ironman race and using that race as part of the training strategy? Is the triathlete prone to running injuries? What is expected to be gained from the brick workout? Individual athlete strengths and weaknesses need to be considered when making training decisions. The bias should be toward conservative undertraining so that the triathlete remains injury free and mentally sharp.
Intermediate and advanced sprint- and Olympic-distance racers often complete brick workouts every 3 to 4 weeks. These workouts are done at the same intensity as other workouts in the macrocycle. The intensity portion of the brick can be structured in multiple ways:
- Aerobic ride followed by an aerobic run.
- Aerobic ride followed by a run that includes some portion at current training-cycle intensity. This run can be a steady effort or broken into intervals.
- Ride that includes some portion at current training-cycle intensity. This ride can be a steady effort or broken into intervals and is followed by an aerobic run.
- Ride followed by a run in which both disciplines include some portion at intensity.
Duathlon T1 is easier to practice than triathlon T1 for most triathletes. Any yard or garage can be turned into a mock T1 area. The duathlete can go for the assigned run, return home, complete the transition, and head out on a bike ride.
The intensity for any run-to-bike workout should match the intensity of the rest of the workouts in that macrocycle. As workout intensity increases with an approaching race day, race-pace run-to-bike workouts can be included in the mix. Examples include the following:
- Run 5 kilometers, doing the last 1.5 kilometers at race pace. Immediately transition to an easy ride of 10 kilometers.
- Run 2.5 kilometers at aerobic intensity. Transition to a 15-kilometer negative-split ride. Begin at aerobic intensity for 7.5 kilometers and then ride the last 7.5 kilometers at close to race intensity. Faster duathletes can finish at zone 3 to 5a intensity and build from zone 3 to 5b in the second half of the ride.
- Run 5 kilometers, doing the last 1.5 kilometers at race intensity. Immediately transition to a ride of 15 kilometers. Make the first 7.5 kilometers at race intensity and finish at aerobic intensity.
The design of the workout should have intent for the duathlete. That intent may be transition practice, muscle recruitment when changing disciplines at an easy pace, or race-pace rehearsal. New and intermediate duathletes may consider making the workout distances less than race distances. Top duathletes may want the distances to be the same as race distances. They may perform only a portion of the workout at race pace so that they save the best performance for race day.