Work on the details: [Y]ou must practice transition training as part of your skill training for WODs or triathlons.
CrossFit WODs such as “Nancy” or “Helen” really test the athlete’s ability to combine strength and endurance in the same workout. Overhead squats and running, or running and then completing KB swings and pull-ups, are taxing on all the systems. In triathlon training, the transition from bike to run is known as a “brick” and it’s accepted that your legs feel like bricks when you start running! The same idea applies for the obstacle course races: you have to be able to climb a rope, jump over a 10-ft wall, and then run to the next station. People will generally say that the obstacles were doable, but it was the running that got hard.
Developing Foot Strength
As you fatigue, the first thing to go is running form. This is why you must practice transition training as part of your skill training for WODs or triathlons. As the WODs get longer, you can start to “hear” people’s feet — literally — as they stomp the ground because their cadence gets lower; they are just doing what they can to finish. If you practice skill drills that develop muscle elasticity and cadence, you will enjoy the benefits in your workouts.
Barefoot drills will both increase your foot strength as well as develop your muscle elasticity.
As you get stronger in your feet as well as increase your pliability, you will be able to maintain higher cadence at higher speeds for longer durations.
Progress slowly on these drills and pay attention to your form. Being able to land softly on a jump barefoot will translate to lighter feet in your run.
Start out hopping on two feet, staying on the balls of your feet but letting your heels touch. As you add the fall to move forward, practice one-foot hops as well.
As you develop more “springiness” in your feet, you can advance to jumping up and off a higher surface — with one or both feet — such as a low curb. Eventually you can progress to jumping onto a much higher box and then stepping off, with a focus on landing softly/quietly on the top.