When I started triathlons I never did brick runs, running immediately after biking, in training.

I did race frequently the second of training so reflecting back on that, I suppose those weekend sprint distance races were by “brick” workouts.

Brick workouts, running after the bike, will bring a different experience, so it is important to include as a regular part of your training plan.

Finding it difficult to run off the bike has been documented. A recent French study found that “70% of elite triathletes ran up to 10% slower in the first 500-1000m of the run leg. Another study showed that transition-phase running is marked by greater oxygen consumption and higher breathing and heart rates”

Running economy is measurably lower after riding, that is why it feels tougher to run after biking then to run on fresh legs.  Incorporating efficient running technique by adding  skills and drills focused on cadence, strength, endurance and speed into your regular weekly training plan will help you run more economically after biking

Factors that affect can present some fatigue and challenges when you make the transition from riding to running. Over time, with practice you will build fitness and strategies so the “brick” is efficient. intensity and duration of your ride

• Your bike intensity and duration
• Your nutrition (both hydration and calorie intake)
• The weather
• Terrain

Duration and intensity while riding will deplete your legs of muscle – hence the feeling of heaviness and unresponsiveness. Intaking calories and hydration can off set how soon your legs become glycogen depleted and dehydration taking its toll

Although biking and running involve large lower body muscles, different movement patterns engage different muscles in different ways, which requires a redistribution of blood from one set of muscles to another.  Riding on hilly terrain, increases biking intensity as well as a variety of muscle pattern recruitment compared to riding on a flatter course as well as running hills or flat.

Riding into a head wind can also increase intensity as well as mental anxiety to fatigue your muscles compared to riding with a tail wind, so average speed is not the determining factor with regards to training intensity.

How to maximize your run off the bike performance

• Practice weekly. Vary your workout distance and be sure to add some race specific intensity. Whether you decide to do a longer brick, 25 plus mile bike and 5k plus s mile run – or a shorter ‘transition run’ – a full bike session followed by a short run (10 minutes, you are conditioning your muscles and your nervous system to cope better with the bike-run transition. Whatever your level of ability, practicing the transition will make a huge difference.
• Lighten the gears slightly as you get towards the end of the bike leg. Give your legs a chance to recover before you have to run – you can save a little energy and gain some ‘fresh legs’ without making major sacrifices of time.
• Minimize glycogen depletion and dehydration by eating a meal within 2 hours of your training time and to eat and drink sufficiently on the bike. Have a clear plan and know how many grams and ounces of liquid (water, electrolyte mix with or without calories)  you need to consume to set yourself up for the run. Drink about about 6 ounces every 15 minutes and intake 40-60 grams of carbohydrate per hour depending on your size and how long you are riding for.
• Give yourself permission to take the first 5-10 minutes to allow your body and mind to ease into the run, find your rhythm’. The priority should first be into getting into a a  groove before you focus on your competition.
• ALWAYS, ALWAYS, ALWAYS be mindful of form as your begin your run off the bike. 
• Run within your fitness and training level. Use your heart rate and gps as tools to help gauge your rate of perceived effort in training and be mindful of RPE while racing since HR and Pace can be effected by fatigue and nutrion, ofter running via RPE while monitoring other variables will lead to a PR. 

Running off the bike can be tough, even for someone like me who has been racing for 25 years.  If you can take a difficulty and turn it into an opportunity, then you’re closer to success. And that’s not just true for triathlon, that’s true for life!