Accessing Animator Component from tagged objects in an Array in Start and then triggering its bool in Update

I want to get the Animator component for each object in my scene tagged "Legs" in the Start Function, and then in the Update function I would like to set the bool "isWalking" from that animator to either true or false based on "if statements".
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So far I have:

 public GameObject[] legs;
 Animator anim;

 // Start is called before the first frame update
 void Start()
 {
     legs = GameObject.FindGameObjectsWithTag("Legs");
     foreach (GameObject obj in legs)
     {
         anim = obj.GetComponent<Animator>();
         anim.SetBool("isWalking", false);
     }

This successfully creates an array with all game objects tagged "Legs", retrieves their Animator Component which I've called 'anim', and sets the "isWalking" bool to false.
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THE PROBLEM is that I seem to only be able to change the Animator's "isWalking" bool when the code is inside the foreach brackets. I need to be able to change it in the Update Function, inside an 'if statement'.
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Any help would be huuuuuuge and I'd be super grateful