McClammer played basketball, tennis and athletics as a child, but injured her spinal cord in a car accident when she was six years old and then she had to start with a wheelchair.

[3] As a freshman in high school, McClammer became the youngest member of Team USA in the 2008 Summer Paralympics in Beijing at 14 years old.

[14] In 2016, McClammer won two silver medals and one bronze in the women's 5,000 meters-T53/54, 4×400 relay-T53/54, and 1500 meter races at the 2016 Summer Paralympics.

[15] The next year, she competed with Team USA at the 2017 World Para Athletics Championships where she won a silver medal with a time of 55.50.

USADA found that the HCTZ appeared as a trace contaminant in a permitted prescription drug, without McClammer's knowledge and without cause of negligence.