3:58 in the LCM 400 IM? An Analysis of Leon Marchand’s Yards-to-LC Meters Conversions

Unless you’ve been living under a rock for the past week, you’ve seen just how incredibly fast Arizona State sophomore Leon Marchand swam at the NCAA Championships in Minneapolis. The French superstar shattered three individual NCAA Records at last week and posted another top relay split of all time in another two events.

Given how jaw-droppingly fast he swam in yards, we thought it would be a fun exercise to look at how Marchand’s SCY-to-LCM time conversions look now. Before we get into it, a quick disclaimer: conversions, especially yards-to-meters conversions, are not an exact science and swimmers’ performances from yards to meters will vary significantly from person to person. That being said, it’s just one tool which we can use to compare times between the courses.

Below, you’ll find a table that shows each of Marchand’s events from the 2023 NCAA Championships (plus a little bonus with the 500 free). Beside his yards time in each event, there is a “classic converter” time, which simply takes into account the added distance. This is the traditional conversion tool that has been around for a long time and many of us have used. Next to the classic conversion is the “SwimSwam Real-Time” conversion, which is a tool we developed which takes into account actual historical data for swimmers from course to course. In theory, this is the more accurate conversion, since it takes the historical data from actual swimmers to create its conversion formula, but even so, there is still going to be variance from swimmer to swimmer. We then put an average of the two conversions, as well as the LCM World Record and Marchand’s current LCM personal bests in the table as well.

Without further ado, here is the data everyone is waiting for:

* = relay split

It’s also worth pointing out that Marchand’s personal best of 4:07.81 in the 500-yard freestyle didn’t come at a championship meet. Marchand swam that time in a dual meet with Arizona in early February. Though he was suited for the swim, we have to assume based on his Pac-12 and NCAAs performances that Marchand would have gone faster than that dual meet time had he elected to swim the event at one of the championship meets. Nonetheless, his 4:07.81 500 free comes out to 3:42.74 when the two conversion tools are averaged, which is still a time which is very much capable of winning an Olympic medal. Coincidentally, the 500 free is the other event Marchand didn’t race at NCAAs, and it’s also the only event where his average of the conversions isn’t under the current World Record.

Perhaps the most head-turning conversion in this table is the 400 IM, where Marchand’s classic conversion comes in at an incomprehensibly fast 3:58.19. That time is notably 5.65 seconds faster than Michael Phelps‘ World Record in the event, which is considered by many in the swimming community to one of the fastest, if not the fastest, men’s World Records on the board currently. Of course, it wasn’t until Marchand himself blasted a 4:04.28 in the 400 IM last summer that anyone had gotten even remotely close to Phelps’ mark from his legendary 2008 Olympics in Beijing.

While we’re briefly on the topic of the 400 IM, we would be remiss if we didn’t mention that Phelps and Marchand share a coach in Bob Bowman. Bowman was famously the only coach Phelps ever had, and it’s definitely worth pointing out that no one had sniffed Phelps’ 400 IM World Record for 14 years, that is until Marchand started training under Bowman and he became the only swimmer other than Phelps to go under 4:05 in the event.

One other interesting note for the 400 IM: Marchand’s “real-time” conversion of 4:04.16 comes in only 0.12 seconds faster than his actual LCM personal best in the event, which makes it an outlier here because all his other “real-time” conversions are well under his PBs.

Marchand’s other two individual events from NCAAs, the 200 IM and 200 breast, come in way under the World Records in the event in the average of the conversions. The 200 breast in particular is an event where Marchand’s LCM progress this summer and next will be very interesting to watch. I don’t think anyone doubts that Marchand has what it takes to bring down to the 200 and 400 IM World Records, but his lifetime best of 2:08.76 in the LCM 200 breast, which he swam last year, is still a bit off that record mark of 2:05.95.

That brings us to an interesting point of conjecture. It will be fascinating to see which LCM events Marchand (and Bowman) decide to focus on, since at this point it seems like he could throw down all-time performances in a number of them. Given what he’s done in his college career, we can probably rule out the 100 free and 100 breast from this list, only because Marchand seems to have more of a passion for racing the longer events. That being said, we’ll certainly still see Marchand competing in those events on France’s relays at major international meets, so he’ll still be posting times in them.

That does bring us to an interesting place, however, as Marchand really could swim any of the five 200s at major international competitions. They weren’t included in his NCAA events this year, but Marchand did swim a 1:53.37 in the LCM 200 fly last summer at World Champs and based off his backstroke splits in his IMs at NCAAs last week, there’s little doubt he couldn’t throw down a great time in the LCM 200 back as well, even though his personal best in the event currently is a 2:11.

We know the 400 IM is a given for Marchand, but there needs to be a real question as to whether he’ll try his hand at the 400 free soon as well. Right now, his PB in the 400 free is a 4:04.65 from 2020.

One thing is for certain: all eyes are going to be on Marchand to see just what he’s capable of in the LCM pool over the next few years, the prospect of which is so exciting for the swimming community.