The bend taxes your left leg and your lane draw decides how much

Running a curve is an asymmetric event dressed as a symmetric one, and the inside lanes pay for it in stride.

Lane two in a 200 metres is not a shorter version of lane seven. The distance is the same, the staggered start sees to that, but the geometry the athlete meets in the first hundred metres is different enough to change how they run, and the sport treats lane assignment as a matter of seeding rather than mechanics.

The tighter the curve, the more of the athlete's force has to point sideways instead of forwards.

That force comes mostly from the outside leg, the right one, pushing the body into the turn, while the inside leg works in a shortened, awkward position with the hip adducted and the foot landing under a body that is leaning away from it. Stride length on the inside drops. Contact time rises. Frequency has to go up to hold the same speed, and it does, which is why a curve is metabolically dearer than the equivalent straight at the same clock speed.

In lane one the effect is pronounced enough that plenty of sprinters simply do not run the same race there. In lane eight, where the bend is gentlest, the complaint is different: you can see nobody, you have no reference for how hard the field is going, and athletes routinely run the first hundred too hard or too easy because they are racing a ghost.

None of this is secret and yet training barely reflects it. Most curve running in training is done on lanes three and four, in a group, in whichever lane is free. If your athlete is likely to be drawn inside at a championship, the tight lanes are a specific skill and they should be practised, including the unglamorous business of holding the shoulders square while the torso leans.

The strength work should probably be asymmetric too, at least in part, and this is where I lose some coaches. The idea of deliberately loading one side more than the other sounds like the beginning of an injury. It is closer to the truth than pretending the event is symmetric.

The stride pattern going into the straight is where you see who did the work. Athletes who fought the bend arrive tight, take one crooked stride at the transition, and never get the speed back.

The bend does not slow you down. It sets up the person who does.