"Brick" workouts, back-to-back combinations of different disciplines such as a swim/bike, bike/run or run/bike/run, should be incorporated into all periods of training: base, build, peak and race. These combination workouts help athletes manage the physical and mental demands of moving quickly from one discipline to the next.
Generally, the most challenging transition for multisport athletes is the bike-to-run, as it is often unsettling to transition from non-weight-bearing cycling to weight-bearing running. Coming off the bike, the body needs to adjust to the different muscles that are used during the run; and, if you have not been training for this, your legs can literally feel like "bricks."
More: The Good, Bad and Ugly of Brick Workouts
Here are two of my favorite brick workouts for the build period:
Trainer-Track Brick
This is a great workout to focus on running off the bike and settling into your race pace. It also provides you the opportunity to practice your bike-to-run transition. This workout should be scheduled in the build period of training as you are dialing into your upcoming "A" race pace. The example below is for an Olympic-Distance Race.
You will need access to a track or other measured course and a bike trainer. Set up your bike and trainer track-side and begin the workout with a 20 to 30 minute warm-up, with the last 5 minutes at your race pace. After the 20 to 30 minute warm-up, hop off the bike, quickly change shoes and ease into your run.
The goal here is to settle into your race pace as quickly and comfortably as possible. Hold this pace for 1 mile and then transition back to the bike for a 15-minute race-pace effort. Repeat this progression for a total of 6 miles of running. After you finish the last mile, head to the bike for 10- to 15-minute recovery spin in the small chainring.
More: Brick Workouts to Help You Finish Fast
Ironman Pacing Brick
This is a great brick for Ironman athletes to work on their IM bike race pace and also a great opportunity to rehearse race-day nutrition. This workout should be completed in the build period of the training plan, as this is where the workouts should become more race-specific. Choose a cycling course that mimics your upcoming "A" race; wear what you will on race day; keep track of your nutrition and hydration; and note your perceived exertion.
