Train the transverse abdominis
Stability on the bike, according to Koshari, who also races BMX, involves use of the transverse abdominis (TVA), one of the deepest layers of abdominal muscle that aids in stability of the pelvis.
The lower-most section of the often-overlooked TVA, Koshari said, is “tricky” to target, and isolation exercises are the most effective way to train it.
He recommends beginning by “laying on [your] back with the feet straight up, and you can hold something between your feet.”
A yoga block, water bottle, or even a sheet of paper are all suitable, as the goal is to use tension in the hip adductors of the inner thigh to keep the legs aligned along the body’s center-line.
“With an exhale, push your heels up one inch. That will lift your tailbone off of the mat one inch,” Koshari said. “If you go higher, then you’re using your mid and upper TVA. So you want to isolate the lower TVA by barely lifting your tailbone off the floor.”
He recommends beginning with 10 controlled repetitions, working up to static holds “three to five breaths” in duration.
As a benchmark, Koshari said that he has performed up to 110 continuous repetitions in a given set.