Both American medley relays seem like slam-dunks to win to wrap up the swimming portion of the 2012 Olympics on Saturday night (though stranger things have happened than slam-dunk upsets, right Chad le Clos?).
For now, though, we want to jump a step forward. These two relays might be the best we've ever seen, especially in the case of the men where the Americans will throw out three gold medalists (Matt Grevers, Michael Phelps, and Nathan Adrian) and a bronze medalist (Brendan Hansen). But with the lofty standards set in polyurethane in 2008 and 2009, can the Americans come close?
Men's Medley
First, we'll look at the current World Record holders:
Aaron Peirsol 52.19
Eric Shanteau 58.57
Michael Phelps 49.72
Dave Walters 46.80
Total: 3:27.28
Despite being arguably the more complete of the two American medley, this men's relay is probably far more out-of-reach. Grevers can certainly match Peirsol's 52.19 leadoff, as we've already seen him do that at this meet. Adrian seems to have a 46.9 or a 47.0 in him on a best day. The two middle legs will be toughest. It would be hard to see Hansen get down to a 58.5, and even for Michael Phelps to split a 49.7 (though, we know his flat-start potential is better than the 51.1 that won the individual for him).
First, here's each swimmer's best individual time at this meet, and then allowed for a very good .5 second relay allowance for each of the last three:
Matt Grevers 52.16
Brendan Hansen 59.49
Michael Phelps 50.86
Nathan Adrian 47.52
Total: 3:30.03
Minus 1.5 (for relay starts): 3:28.53
Here is the best case scenario that I could see happening, if everyone peaked and hit their starts (splits, not flat starts):
Matt Grevers 52.0
Brendan Hansen 58.8
Michael Phelps 49.9
Nathan Adrian 46.85
Best Case Total: 3:27.55
The conclusion: not likely, but not impossible. Even in a very favorable, best-case scenario where the Americans aren't fatigued from a long meet, and nobody has an off race, they would be hard-pressed to get to a 3:27.2.
Women's Medley
If this were a 4×200 medley relay, then the answer might be a “no-brainer”. With Missy breaking the World Record in the 200 back, and Rebecca Soni breaking the World Record in the 200 breaststroke, they'd have a good head start.
Regardless, the American women lead off this relay with three women who broke World Records in textile suits (Missy Franklin, Rebecca Soni, and Dana Vollmer). We presume they'll anchor with a swimmer in Allison Schmitt who is the 2nd-best 200 freestyler in history, and this year has found herself the best speed of her career. Plus, the Chinese relay that broke this record in 2009, in hindsight, just wasn't that complete. The old record:
Zhao Jing 58.98
Chen Huijia 1:04.12
Jiao Liuyang 56.28
Li Zhesi 52.81
Total: 3:52.19
Two of those legs are slam-dunks. Though it was many, many swims ago, Franklin blew away that 100 backstroke time in the individual by almost a second. Vollmer's flat-start time was better than Liuyang's swim on a relay start, and she lost one of her caps and had a bad finish.
The other two legs are somewhat dicier. As good as Soni is, her 100 hung in the upper 1:05 range at this meet. However, with loads of confidence under her from the 2:19 in the 200, she should certainly be able to split a 1:04-mid, based on what we know she's capable of. Schmitt will be the key at the end. She split a 53.5 on the 400 free relay, which lines up pretty fairly with her best flat-start time of 2012 (though not from this meet) of 53.9, which we'll use for the comparison. Below, flat-start times.
Missy Franklin 58.33
Rebecca Soni 1:05.55
Dana Vollmer 55.98
Allison Schmitt 53.94
Total: 3:53.80
Minus 1.5 (for relay starts): 3:52.30
The above shows that the Americans are already right on top of it just by repeating what they've already done, with good but not great relay starts. Missy's split is probably about maxed-out, but everybody else in this group, theoretically, can be better, and if each improved by a tenth, this record would be gone. Here's our idea of best-case splits, with relay starts already factored in:
Missy Franklin 58.3
Rebecca Soni 1:04.6
Dana Vollmer 55.3
Allison Schmitt 53.3
Best Case Total: 3:51.50
Conclusion: the women definitely have a shot. They wouldn't even need to be perfectly perfect, as the men would.
The reality: These relays are going to be way out in front, more-than-likely. They're not going to be pushed in the water, and they'll have no reason to push their relay starts and risk a disqualification. When a team is this much of a favorite, they usually need to really be better than the old World Record to break it, because most wouldn't risk the gold for the record.