Swimmer profile
Mackenzie O'Brien
Female11-12Tollefson SwimmingPV · EASTERN
SeasonUSA Swimming season runs Sept – Aug
Event
2022–23
2023–24
2024–25
2025–26
50 Free SCY
58.21
37.74
▲ 20.47
34.40
▲ 3.34
30.87
▲ 3.53
100 Free SCY
—
—
1:20.98
1:09.66
▲ 11.32
200 Free SCY
—
—
3:03.68
2:41.59
▲ 22.09
50 Back SCY
—
—
41.85
37.18
▲ 4.67
100 Back SCY
—
—
1:38.06
—
50 Breast SCY
—
58.68
41.18
▲ 17.50
37.22
▲ 3.96
100 Breast SCY
—
—
1:32.28
1:20.92
▲ 11.36
200 Breast SCY
—
—
—
3:08.84
50 Fly SCY
—
48.07
39.56
▲ 8.51
34.56
▲ 5.00
100 Fly SCY
—
—
—
1:34.74
100 IM SCY
—
1:36.79
1:27.67
▲ 9.12
1:17.32
▲ 10.35
200 IM SCY
—
—
—
2:48.88
Improvement<0.5s0.5–2s2–5s5s+Slower
📊 All Attempts by Event
Chronological history of every recorded swim. Click an event to expand its attempt list.