The organelle responsible for producing energy for the roadrunner's muscles is the mitochondria. When this organelle does not work efficiently, the roadrunner cannot produce enough ATP (adenosine triphosphate), making it difficult to run fast.
Another structure affected by dehydration is the cell membrane. When this structure cannot retain water properly, the cells lose their turgor pressure, which weakens their structure and function.
Because of these organelle problems, the roadrunner's muscles do not have enough energy (ATP) and the cells are dehydrated, leading to slower running speed.