Negative splitting is every endurance athlete's secret weapon. Although it may sound like a painful (if not impossible) gymnastics maneuver, negative splitting is really a racing technique that in theory is very simple but in execution takes discipline and a healthy dose of endurance.
Essentially a strategy that involves swimming (or running or cycling, for that matter) the last half of your race at a faster pace than the first half, negative splitting is the best way to overtake your competitors and probably the smartest way to race if you have the ability.
Janet Evans's self-admitted, best-ever race was her 400-meter freestyle at the 1988 Seoul Olympic Games. It was the only race she negative split in her life, with her first 200 meters a 2:03 and her last 200 meters a 2:01.
Not everyone is destined to be a negative-split performer. Personally, I always had difficulty negative splitting in my endurance races because I liked to set the tone of my swims early and get out in front of the competition. However, I have found it easier to negative-split as a runner, having back-halved my last two marathons in a split time nearly a minute faster than my first 13.1 miles. Go figure.
Naturally, in a race situation most people try hard the moment the gun goes off, even if they are pacing themselves for a longer event. To perform a negative split, however, it is important to hold back a bit and race at a speed that you are comfortable with while remaining competitive with the rest of the field.
How do you know what speed that is? One way is to familiarize yourself with your endurance capabilities during practice and rely on that knowledge to pace yourself in competition. For example, here is a set you can complete to learn about your personal endurance:
10 x 100 @ 10 seconds rest
Start the set at what you think is 85 percent effort, and hold that time for each 100 for the first five. On No. 6, increase your effort to 90 percent and see if your time drops by a second or two. On 7, 8, 9 and 10, increase your effort each time so that you are sprinting by the end of the set.
If your times decrease, you are either in great condition to be a negative-split swimmer (because you basically swam a broken 1,000 yards with the last half being faster than the first half), or you did not start out as fast as you should have.
If the latter is the case, attempt the set again with a faster first-100. In time, you will recognize what maximum speed you can maintain while still having something left to back-half your race.
If your times in the test set get slower, then you need to work on your endurance and perhaps begin the set at a more conservative clip. The best endurance-developing sets are ladders--as well as the above set--repeated daily until you start to complete it correctly (with the last 5x100 being faster than the first five).
If your times remain the same for all 10x100, then your endurance is commendable but your pacing self-awareness is off (you should not have to sprint the same time for your 10th 100 that you did at 85 percent effort on your first 100).
Another set helpful in achieving negative split capabilities is:
10 x 100: (2 @ 1:30, 2 @ 1:25, 2 @ 1:20, 2 @ 1:15, 2 @ 1:10, for instance)
This set forces you to swim faster because your interval decreases with each pair of 100s. It is important to pick a starting interval that is challenging enough for you to swim at 85 percent effort, but comfortable enough for you to descend your effort, your times and your interval in the 100s that follow.
Regardless of the outcome, the sets above will indicate what kind of a swimmer you are and what you need to do to develop the negative-split technique. Once you are comfortable and familiar with your various pace capabilities, you can start to implement them in competition.
For instance, if you are in an open-water swim or a running marathon, start out like you did on the 10x100 sets, at 85 percent effort. You may find that the excitement of the race boosts your speed, so be careful not to overexert yourself early. At the halfway point, focus on competitors in front of you and reel them in, one by one, while raising your effort by a few percentage points. By the end of the race, you should feel like you are sprinting at the finish.
An added benefit to negative splitting is the mental advantage you have over your competitors. Everyone is fatigued after the first half of their race. If you manage to go by these weary folks as if they're standing still, not only will you psyche them out but you also will psyche yourself up and give yourself an unexpected psychological boost.
Negative splitting by nature is not supposed to feel good or be easy. But as painful as the race may feel for you, it will feel a lot worse for the people you are passing.