In the case of Toyota Motor Manufacturing, Kentucky, Inc. v. Ella Williams in 2001, the U.S. Supreme Court ruled on a matter related to the Americans with Disabilities Act (ADA). Ella Williams was an employee at Toyota's manufacturing plant who developed carpal tunnel syndrome and tendinitis due to her work responsibilities that involved repetitive tasks using her hands and arms. After being reassigned to different roles within the company that also aggravated her condition, she filed a lawsuit claiming disability discrimination under ADA as she could not perform manual tasks associated with her job without suffering pain or risk of injury. The court had to determine whether Williams' impairments constituted a disability under ADA - specifically if they substantially limited one or more major life activities. The Supreme Court unanimously held that they did not because "substantially limits" refers to significant restrictions in performing tasks central to most people’s daily lives rather than specific limitations faced by an individual at their workplace. Therefore, while acknowledging William's physical conditions were indeed limiting for certain jobs within Toyota's factory setting; it didn't render her generally incapable of manual task performance which is what would be required for protection under ADA.

In the dissenting opinion for Toyota Motor Manufacturing, Kentucky, Inc. v. Ella Williams (2001), Justice Stevens argued that the majority's interpretation of "substantially limits" was too narrow and inconsistent with Congress' intent when it enacted the Americans with Disabilities Act (ADA). He contended that by focusing on a limited range of manual tasks to determine if an individual is substantially limited in performing manual tasks, the court ignored other relevant factors such as pain experienced while performing certain activities or limitations outside work context. Furthermore, he disagreed with requiring comparisons between individuals to establish disability under ADA because this approach could lead to arbitrary results and undermine ADA’s purpose of eliminating discrimination against disabled persons. Instead, he proposed a broader view where any impairment causing significant restriction in one's ability to perform a class of jobs should be considered substantial limitation.