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Analysis of an Interval Run

BY Ryan Bolton

After focusing on the marathon, elite runner Caroline Rotich needed speed to prepare for an upcoming 10k. Her coach, Ryan Bolton, gives an inside look into the difficult interval workout he prescribed, and discusses her execution of the workout.

How and when to perform speed work is a common question among endurance athletes and coaches. As the coach of The Harambee Project, I monitor this balance closely with all of my athletes. One runner, Caroline Rotich, was entering a portion of her season focused on speed for upcoming 10k races after an early season focused on a the Tokyo marathon. Here is a look into a difficult negative split interval workout she did to get speed back into the legs.

The Workout

20 minutes warm up with drill and strides. Then, 2000 with the first K in 3:20 to 3:25 (in control) and the second k in 3:00 to 3:05! (4:30 rest), 1200 with the last 400 fast (shoot for 70 to71 or so per lap in the first 800 meters, then finish with sub 68)(4:30 rest), 800 with last 300 fast (shoot for 1:35 or so and then sub 48)(4:30), 400 with last 200 fast (31 or under). The focus here is on quality. Full recovery after each interval. 15 minutes cool down.

This is a high quality workout that requires a hard closing effort each interval. The main goal is to get the athlete running at a threshold level pace and then finishing fast. In many of their races, closing speed is essential, so training the body to switch gears and close fast is important. Overall, the workout is only 4400 meters, which is short for a marathon runner like Caroline.

However, Caroline was in a part of her season where we were focusing on a few shorter races to build speed. Our usual approach is more traditional in that we build up a big base and then work on tempo, strength and speed. This year is different due to her race schedule (running a marathon in later November after running the Tokyo marathon in February (4th place; 2:24:35). Therefore, I introduced a block of more high intensity speed mid-season to sharpen her up for shorter races.

After this phase of training and racing we’ve went back into a more endurance and tempo oriented block to start building for the Fall marathon season that will start with a half marathon in September.


Caroline ran this workout with 4 other athletes. One of the other athletes was a pacer that kept her on track and held basically the same pace. For an athlete at this level running times like this, I find that having appropriate training partners is essential. For women it’s easier to find training partners in elite or sub elite men that are training at a high level. For some of the fast men it’s much harder to find people that can keep up.

The workout was ran at approximately 6000 feet in altitude just outside of Santa Fe, NM, with the warm up starting at 8:00 a.m. It was slightly breezy with a temp of around 75 degrees Fahrenheit. Definitely getting a bit hot by the end. Heart rate was not monitored, as it usually isn’t with my elite athletes. They run based on goal times and feel more than heart rate. Being that I spend nearly every day with these athletes, running workouts based on goal times is much more possible.

Results of the Workout 

After a 20 minute warm up with strides and drills (watch was off during the strides and drills), we started the workout. Take a look at the TrainingPeaks file to see the splits, recoveries, etc.

2000: 6:22. The first 1k was in 3:22 and the last 1k was in 3:00. Perfect. The first 1000 was right around 5:25 mile pace, which was smooth and comfortable. Then, the last 1000 was quick and at 4:49 mile pace. The average pace for the entire 2k was 5:07 per mile.

1200: 3:38. The first 800 meters was in 2:31 (5:02 mile pace) and the last 400 meters was in 1:07 (4:28 mile pace) for an average speed of 4:52 per mile pace. Once again, a solid negative split.

800: 2:22. The first 500 meters was in 1:32 (4:56 per mile pace) and the last 300 meters was in :50 (4:28 pace). This was very similar to the result of the 1200. I would have liked the 300 to be just a bit faster, but overall was happy with this interval. Another substantial negative split.

400: 1:06. Split into 200s; the first being at :34 and the second a :32. A quick finish to a strong workout.


Sometimes, workouts go exactly as planned. On this day, that was the case. Caroline hit all of the goal times and negative split each interval perfectly. The first part of each interval was smooth and in control allowing for Caroline to finish strong every round. This workout not only provided a good fitness boost, it also instilled confidence going into an upcoming race (see below).

Post Script 

On July 27th, Caroline won the Wharf to Wharf 6 miler in Santa Cruz, CA in the time of 30:16. That’s approximately 5:02 mile pace. Aliphine Tuliamuk, who ran the same workout in very similar times was 3rd in 30:42. Based on the workout that was about 10 days prior, this is right where I expected her to be.

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About Ryan Bolton

Ryan Bolton is the Founder/Director/Head Coach of Bolton Endurance Sports Training (B.E.S.T.) and The Harmabee Project based in Santa Fe, NM. He is also an elite level coach with Training Bible Coaching. After a successful college running career that included All-American and Academic All-American honors, Bolton became a professional triathlete with a sole focus of competing in the Olympic Games. In 2000, Ryan represented the United States in the Sydney Olympics and then went on to compete at a top level in long course triathlon racing. In 2004, Bolton received an MS in Human Nutrition, with an emphasis on stress metabolism in 2006. Combined with his BA in Exercise physiology and long term background in endurance sports, this education provided Ryan with a perfect background for top level coaching. To contact Ryan, email him at, and follow him on Twitter @CoachRyanBolton.