Mackenzie O'Brien

Fage 15CZMIMIMMAWILL

232 plausible swims · 32 meets · 2024-05-18 → 2026-06-26

Personal records

Event	Course	Best	Cut	Date	Meet
50 Freestyle	SCY	24.08	AAAA	2026-02-28	2026 JAWS "Last Chance" Meet venue
100 Freestyle	SCY	53.02	AAA+0.43s to AAAA	2026-02-08	2026 Grand Rapids Open venue
200 Freestyle	SCY	1:58.70	AAA+5.21s to AAAA	2026-02-07	2026 Grand Rapids Open venue
500 Freestyle	SCY	5:31.01	AA+10.32s to AAA	2026-02-08	2026 Grand Rapids Open venue
1650 Freestyle	SCY	20:07.22	A+40.03s to AA	2024-11-01	Greater Kalamazoo Arena Challenge venue
50 Backstroke	SCY	27.37	AAA+0.38s to AAAA	2026-03-01	2026 JAWS "Last Chance" Meet venue
100 Backstroke	SCY	59.13	AAA+2.14s to AAAA	2026-02-08	2026 Grand Rapids Open venue
200 Backstroke	SCY	2:11.14	AA+1.65s to AAA	2026-03-01	2026 JAWS "Last Chance" Meet venue
50 Breaststroke	SCY	31.49	AAA+0.10s to AAAA	2026-03-01	2026 JAWS "Last Chance" Meet venue
100 Breaststroke	SCY	1:10.88	AA+2.19s to AAA	2026-02-07	2026 Grand Rapids Open venue
200 Breaststroke	SCY	2:35.54	A+0.95s to AA	2026-02-08	2026 Grand Rapids Open venue
50 Butterfly	SCY	25.93	AAAA	2024-10-18	2024 Boo Bash Invitational
100 Butterfly	SCY	58.43	AAA+1.64s to AAAA	2026-02-07	2026 Grand Rapids Open venue
200 Butterfly	SCY	2:17.22	AA+5.03s to AAA	2026-03-07	2026 Lake Superior Regional Meet venue
100 Individual Medley	SCY	50.49		2024-10-05	2024 Fall Tune-Up
200 Individual Medley	SCY	2:12.68	AAA+5.99s to AAAA	2026-03-01	2026 JAWS "Last Chance" Meet venue
400 Individual Medley	SCY	4:53.79	AA+8.70s to AAA	2025-12-05	EGRA 2025 Winter Washout venue
50 Freestyle	LCM	27.92	AAA+0.33s to AAAA	2026-03-28	2026 Central Zone East Spring Speedo Sectiona venue
100 Freestyle	LCM	57.59	AAAA	2024-06-21	2024 Summer Solstice Meet
200 Freestyle	LCM	2:23.85	A+2.16s to AA	2025-07-25	2025 LC ULTRA Championship Meet
400 Freestyle	LCM	4:47.15	AA+1.96s to AAA	2024-05-31	MLA Big Red Challenge
800 Freestyle	LCM	10:43.63	BB+2.74s to A	2025-06-21	2025 Summer Solstice Meet venue
1500 Freestyle	LCM	20:24.01	A+47.72s to AA	2024-06-14	JAWS Sun & Fun slow pool
50 Backstroke	LCM	29.43	AAAA	2025-08-07	2025 Central Zone 14 & Under Championship Mee
100 Backstroke	LCM	1:08.17	AAA+1.88s to AAAA	2026-03-28	2026 Central Zone East Spring Speedo Sectiona venue
200 Backstroke	LCM	2:43.40	BB+0.61s to A	2025-06-22	2025 Summer Solstice Meet venue
50 Breaststroke	LCM	37.00	AA+0.01s to AAA	2026-06-06	MLA Big Red Challenge fast pool
100 Breaststroke	LCM	1:24.45	A+2.16s to AA	2026-06-07	MLA Big Red Challenge fast pool
200 Breaststroke	LCM	3:17.55	BB+11.76s to A	2025-06-14	2025 JAWS Sun & Fun venue
50 Butterfly	LCM	28.97	AAAA	2026-03-26	2026 Central Zone East Spring Speedo Sectiona venue
100 Butterfly	LCM	1:05.72	AAA+1.43s to AAAA	2026-03-27	2026 Central Zone East Spring Speedo Sectiona venue
200 Butterfly	LCM	2:44.51	BB+0.92s to A	2025-06-08	MLA Big Red Challenge venue
200 Individual Medley	LCM	2:28.11	AAA+2.22s to AAAA	2024-06-14	JAWS Sun & Fun
400 Individual Medley	LCM	5:43.02	A+2.93s to AA	2025-06-13	2025 JAWS Sun & Fun venue

Cuts are USA Swimming single-age motivational standards (B → AAAA) at age 15.

Pool tags are a venue speed heuristic (median deviation of all swims there vs each swimmer's typical time) — see the venue page for the method.

Fastest relay legs

Leg	Course	Time	Start	Relay	Date	Meet
50 Freestyle	SCY	25.12	flat	200 Free Relay	2025-03-23	2025 ULTRA Championship Meet
50 Freestyle	SCY	23.73	flying	200 Free Relay (leg 4)	2025-10-18	2025 HS Girls MISCA Meet
100 Freestyle	SCY	54.79	flat	400 Free Relay	2025-03-07	2025 SCY MAGS Championship Meet
100 Freestyle	SCY	52.40	flying	400 Free Relay (leg 4)	2025-10-18	2025 HS Girls MISCA Meet
50 Backstroke	SCY	29.85	flat	200 Medley Relay	2025-03-09	2025 SCY MAGS Championship Meet
100 Backstroke	SCY	1:02.33	flat	400 Medley Relay	2025-03-22	2025 ULTRA Championship Meet
50 Freestyle	LCM	30.47	flat	200 Free Relay	2024-07-28	2024 LCM ULTRA Championship Meet
50 Freestyle	LCM	27.47	flying	200 Free Relay (leg 2)	2026-03-28	2026 Central Zone East Spring Speedo Sectiona
50 Freestyle	LCM	29.66	flying	200 Medley Relay (leg 4)	2024-07-28	2024 LCM ULTRA Championship Meet
100 Freestyle	LCM	1:02.35	flat	400 Free Relay	2025-07-25	2025 LC ULTRA Championship Meet
100 Freestyle	LCM	1:00.78	flying	400 Free Relay (leg 2)	2026-03-27	2026 Central Zone East Spring Speedo Sectiona
50 Butterfly	LCM	29.18	flying	200 Medley Relay (leg 3)	2026-03-27	2026 Central Zone East Spring Speedo Sectiona
100 Butterfly	LCM	1:07.18	flying	400 Medley Relay (leg 3)	2026-03-29	2026 Central Zone East Spring Speedo Sectiona

Reconstructed from relay split marks. Flat = lead-off (comparable to individual times); flying starts run ~0.5–0.7s fast and are not PRs.

IMX / IMR

IMX 15-16 · SCY

4586 points (6/6 events)

Event	Time	Points
500 FR SCY	5:31.01	750
200 BK SCY	2:11.14	799
200 BR SCY	2:35.54	721
200 FL SCY	2:17.22	744
200 IM SCY	2:12.68	828
400 IM SCY	4:53.79	744

IMR 15-16 · SCY

4139 points (5/5 events)

Event	Time	Points
200 FR SCY	1:58.70	835
100 BK SCY	59.13	853
100 BR SCY	1:10.88	753
100 FL SCY	58.43	870
200 IM SCY	2:12.68	828

Scored against AAAA motivational base times: ordering is exact, absolute points run ~25% above the official USA Swimming scale.

PR splits

100 Freestyle SCY 53.02

25.54

27.48

Front half 25.54s · back half 27.48s

200 Freestyle SCY 1:58.70

27.97

29.90

30.25

30.58

Front half 57.87s · back half 60.83s

500 Freestyle SCY 5:31.01

28.81

32.27

32.87

33.58

33.52

34.13

34.08

34.33

34.27

33.15

Front half 161.05s · back half 169.96s

1650 Freestyle SCY 20:07.22

31.06

34.92

35.91

35.88

35.80

36.34

36.35

36.45

36.87

36.81

37.20

37.05

37.27

37.02

37.56

37.27

37.04

37.89

36.99

37.49

37.64

37.32

37.69

37.26

37.37

37.14

37.13

37.28

35.85

36.22

36.13

33.97

100 Backstroke SCY 59.13

28.65

30.48

Front half 28.65s · back half 30.48s

200 Backstroke SCY 2:11.14

30.18

32.40

34.30

34.26

Front half 62.58s · back half 68.56s

100 Breaststroke SCY 1:10.88

32.96

37.92

Front half 32.96s · back half 37.92s

200 Breaststroke SCY 2:35.54

34.89

40.02

40.48

40.15

Front half 74.91s · back half 80.63s

100 Butterfly SCY 58.43

27.20

31.23

Front half 27.20s · back half 31.23s

200 Butterfly SCY 2:17.22

28.32

33.96

36.59

38.35

Front half 62.28s · back half 74.94s

200 Individual Medley SCY 2:12.68

27.63

32.31

40.65

32.09

Front half 59.94s · back half 72.74s

400 Individual Medley SCY 4:53.79

29.51

34.59

36.39

36.41

42.70

44.09

35.56

34.54

Front half 136.90s · back half 156.89s

800 Freestyle LCM 10:43.63

36.90

38.95

41.24

39.48

41.86

40.26

41.78

40.55

41.91

40.33

37.17

45.30

36.53

45.17

37.11

39.09

Front half 321.02s · back half 322.61s

1500 Freestyle LCM 20:24.01

36.35

38.91

42.13

40.85

41.95

40.97

41.73

40.86

38.92

44.33

41.34

40.57

42.46

41.46

38.96

43.83

42.47

40.64

42.37

40.37

41.94

40.52

41.58

40.27

41.36

40.51

39.53

38.87

39.89

38.07

Front half 611.79s · back half 612.22s

100 Backstroke LCM 1:08.17

33.20

34.97

Front half 33.20s · back half 34.97s

200 Backstroke LCM 2:43.40

38.23

42.86

41.05

41.26

Front half 81.09s · back half 82.31s

100 Breaststroke LCM 1:24.45

39.26

45.19

Front half 39.26s · back half 45.19s

200 Breaststroke LCM 3:17.55

45.33

50.01

52.86

49.35

Front half 95.34s · back half 102.21s

100 Butterfly LCM 1:05.72

30.10

35.62

Front half 30.10s · back half 35.62s

200 Butterfly LCM 2:44.51

35.10

41.68

45.67

42.06

Front half 76.78s · back half 87.73s

400 Individual Medley LCM 5:43.02

35.23

41.39

44.70

42.95

51.10

50.07

40.47

37.11

Front half 164.27s · back half 178.75s

Reaction time

fastest 0.64s average 0.645s slowest 0.65s 2 electronic starts

Start reaction over time faster starts higher

From electronically-timed starts only (~2% of corpus swims carry a reaction time). PRs with a recorded reaction show an RT chip in the splits section above.

Progression

Faster times are higher. One card per event, all courses & history.

50 Freestyle SCY 24.08 7 swims

100 Freestyle SCY 53.02 6 swims

200 Freestyle SCY 1:58.70 6 swims

500 Freestyle SCY 5:31.01 3 swims

1650 Freestyle SCY 20:07.22 1 swim

50 Backstroke SCY 27.37 4 swims

100 Backstroke SCY 59.13 4 swims

200 Backstroke SCY 2:11.14 4 swims

50 Breaststroke SCY 31.49 3 swims

100 Breaststroke SCY 1:10.88 4 swims

200 Breaststroke SCY 2:35.54 4 swims

50 Butterfly SCY 25.93 10 swims

100 Butterfly SCY 58.43 4 swims

200 Butterfly SCY 2:17.22 3 swims

100 Individual Medley SCY 50.49 7 swims

200 Individual Medley SCY 2:12.68 6 swims

400 Individual Medley SCY 4:53.79 2 swims

50 Freestyle LCM 27.92 22 swims

100 Freestyle LCM 57.59 14 swims

200 Freestyle LCM 2:23.85 7 swims

400 Freestyle LCM 4:47.15 5 swims

800 Freestyle LCM 10:43.63 2 swims

1500 Freestyle LCM 20:24.01 1 swim

50 Backstroke LCM 29.43 13 swims

100 Backstroke LCM 1:08.17 19 swims

200 Backstroke LCM 2:43.40 4 swims

50 Breaststroke LCM 37.00 8 swims

100 Breaststroke LCM 1:24.45 6 swims

200 Breaststroke LCM 3:17.55 2 swims

50 Butterfly LCM 28.97 16 swims

100 Butterfly LCM 1:05.72 19 swims

200 Butterfly LCM 2:44.51 1 swim

200 Individual Medley LCM 2:28.11 13 swims

400 Individual Medley LCM 5:43.02 2 swims