Early in your training, incorporate a weekly “brick” session. A “brick” is a workout where you complete a bike ride and immediately follow it with a run. As you get closer to the race each time you get off your bike, go for a short run, even if its only 5min. This will force your legs to get use to firing the right muscles (a change from quads to hamstrings and calves) and sending blood to the appropriate muscles needed for performance.
In the seamless triathlon, the run starts well before you hit the transition. In the last 5min of the bike start thinking, “run” and prepare. First, get out of the saddle and ride a couple hundred meters standing. This will wake up your running muscles. Next, sit back down and spin in an easy gear. This will help prepare your legs for the faster stride of running, making it feel less awkward. These steps will help prepare your body for the change in activity and decrease the chance of cramping.
If you notice any unresolved tightness or abnormal stiffness complete a thorough running assessment to find and eliminate any imbalances.