Comments and questions on the how to run a 3 hour marathon post inspired this post on how to run a 1.5 hour half marathon. There is some interest in how to adapt the marathon plan for a half marathon. This post presents a minimalist half marathon training plan. It details a suggested approach to training for a particular half marathon goal. The end of the post details my experiences using it to prepare for my own personal goal of a 1.5 hour half marathon.
After a bit of thinking about how to change the marathon plan into a half marathon plan, my first crack at it was to just simply:
Cut all the Training Distances in Half
Cut the Duration of the Build up in Half from 14 Weeks Down to 7 Weeks
Seems logical. A half marathon is half the distance of a full, so just do half the distance in the training sessions. And spend half the amount of time preparing in the build up.
Cutting all the training distances in half yields three weekly dedicated sessions consisting of:
- Long run of 10 miles starting easy and finishing with the last two miles at race pace
- Tempo run at half marathon race pace not to exceed 6 miles including warm up
- Intervals of Yasso-style 400 meter (quarter mile) repeats with 2:00 recovery
Adopt similar rules as the Full Marathon plan:
- Only Three Days of Dedicated Training per Week
- No Back to Back Training Days
- Other than Changes in Duration, The Training Sessions Remain the Same throughout the 7 Weeks
As long as they are spaced out, what days of the week you dedicate to the training sessions is not that important. Typically Monday, Wednesday and Friday works well. The order of the training sessions is not critical. From experience, the order that works best for me is Long Run, Tempo Run, Interval Session.
The long run consists of a slow easy run of about 8 miles followed by 2 miles at goal half marathon pace for a total of 10 miles. The session is the same throughout the 7 week progression.
The tempo run consists of a 1 mile warm up followed by 2 to 5 miles at goal half marathon pace. The amount of miles run at goal half marathon pace builds for 5 weeks then back off for the last 2 weeks as follows:
Week Half Marathon Pace Distance
- 1 2
- 2 3
- 3 4
- 4 5
- 5 5
- 6 4
- 7 2
The Yasso-style 400 meter (quarter mile) repeats are done at a time derived from your goal half marathon time. Take your half marathon goal time in hours and minutes and express it as minutes and seconds. For example, if your half marathon goal is 1:30:00 (one and a half hours), your 400 meter interval time becomes 1:30 (one and a half minutes). The rest or recovery interval between each 400 meter interval is 2:00 (two minutes) at a very slow run or a quick walk pace. Remember to do a sufficient 1 to 2 mile easy run warm up before you jump into the fast running intervals.
The build up and taper through the 7 weeks would be:
Week Number of Repeats
- 1 2
- 2 4
- 3 6
- 4 8
- 5 10
- 6 8
- 7 2
There are two requirements that need to be in place before attempting to attain the particular half marathon goal of 1.5 hours.
- Be able to run a 5K in 20 minutes
- Have a history of running 3 hours a week or more for the last year
Fueling and Hydration
If you are healthy, there is no need to fuel during a half marathon. Unless the race is held under high heat conditions there is also no need to drink during a half marathon. Exception might be if you are of large size and taking much longer than 1.5 hours. For most people, the training sessions and the race is short enough that you can just ignore fueling and hydrating. This makes the training for and racing a half marathon much simpler than a marathon.
What Limits Half Marathon Speed – The Theory
Your half marathon performance is limited by your aerobic threshold. A half marathon is typically run right at your aerobic threshold. That is the speed at which metabolic waste first begins to accumulate in the blood and tissues at a rate greater than your body can buffer and process it. At speeds faster than aerobic threshold, muscle failure from the accumulated waste (acidosis) will eventually slow you down to the point where your body can recover and begin to clear the waste. So if you want to improve your half marathon speed, you need to improve your aerobic threshold. Tempo runs at half marathon speed are an effective way to boost aerobic threshold. So are the short intervals at faster than goal half marathon pace.
For comparison, a full marathon is typically run just under aerobic threshold speed. In theory, you should be able to hold this speed until you run out of energy (stored glycogen). Energy depletion typically occurs between mile 18 and 20. Unless you are fueling, this exhaustion of stored glycogen will force you to slow way down (hitting the wall).
Besides energy depletion, the length of the marathon also introduces other factors that limit performance and complicate marathon training and racing. These include dehydration, over heating, neurotransmitter depletion and accumulated tissue damage to the muscles and tendons.
In the later stages of the marathon, damage to the tendons limits their elasticity forcing the muscles to work harder to go the same speed. Muscle damage limits the number of working muscle fibers left to do the work thus limiting strength and spring. The feeling of this tissue damage is stiff painful legs. Runners call this feeling dead legs, log legs, zombie legs. At this point, the muscles are prone to seizing up, cramping and tearing. The training to make your legs less prone to tissue damage consists of strength training (weight training) and eccentric loading of the muscles from downhill running.
Fortunately, the half marathon is short enough that energy depletion, dehydration, over heating, neurotransmitter depletion and tissue damage rarely occur are usually not limiting factors to performance.
It has been over 10 years since I successfully employed the minimalist marathon training plan to run a marathon in under 3 hours. Since then, I have gotten older and slower. I turn 63 in 2020. I’ve also sustained a major injury to my left leg in a freak accident that has permanently deformed and weakened my leg. This injury has noticeably compromised my strength, coordination and ability to run fast. Realistically, a 3 hour marathon is probably out of my reach at this point in life. Carrying out the training required, even using a minimalist approach, leads me to injury.
A 3 hour marathon for a 60 plus year old man is a very respectable accomplishment. Not rare, but not all that common. When you get up to 70 years old, I think only two 70 plus year old men have ever done it. For women, I think only one women in their 60’s has run a 3 hour marathon. Famed former elite marathoner Joan Benoit Samuelson has set a 3 hour marathon as a goal and has come close. She has commented that at 60+ years old it is difficult to do the training required without getting injured.
Joan Benoit Samuelson 3:04 Boston Marathon 2019
Since I probably will never be able to do a sub 3 hour marathon again, I thought I would adjust my goal to do a half marathon at sub 3 hour marathon pace – a 1.5 hour half marathon. My last 1.5 hour half marathon was 8 years ago, but maybe, just maybe, I could do a half marathon in 1.5 hours one more time before old age shuts the door on that possibility.
Even though I haven’t been able to quite attain the prerequisite 20 minute 5K time outlined above, some recent 10K and half marathon times gave me hope. My speed curve is rather flat – my pace does not drop off that much as the distance goes up. With age, this seems to be the case. Performance at shorter distances deteriorates with age more than it does at longer distances.
So I began this half marathon training plan the end of November 2019 with the goal of running a sub 1:30:00 half marathon at the Saint George Utah Half Marathon on January 18, 2020. Given my lack of ability to run fast, this was not going to be easy. I would essentially have to hold my recent 5K race pace for an additional 10 miles without stopping.
As I began the 7 week training block, I was not able to do more than a couple miles at my goal half marathon race pace. As the weeks went by, I eventually built up to 5 miles at race pace for my tempo session. My 2 mile time at the end of the 10 mile long run dropped from 14 minutes down to 13 minutes by week 5. Things were moving in the right direction. The Yasso 400 intervals were a challenge for me. Given my compromised ability to run fast, they felt as though I was sprinting full tilt. As the weeks progressed, they did get a bit easier.
Race Day Strategy
The initial plan for the race was to start with the 1:35 pace group for the first mile, keep the 1:30 pace group in sight, reigning them in by half way and then hanging on till the finish. The Saint George Half Marathon has pace groups. I took full advantage of them.
As the race started, the 1:35 pace group felt a little sluggish and I found myself not far behind the 1:30 pace group by the 1 mile marker. There was a tightly bundled pack of about 20 runners running with the 1:30 pacer so I joined in and just hung with them for the first 7 miles.
If you have never run a road race with pace groups, I recommend it. There is a lot of synergy and camaraderie between a pack of runners all running the same speed with the same ultimate goal. There is little talk among the pack as most people in the group are working hard at the edge of their ability. Just the sound of breathing and feet hitting the pavement in a quick rhythm.
The Saint George Half Marathon is a challenging course. It starts along the Virgin River then climbs 300 feet in the first half as it twists and turns up through the Bloomington Hills. It is a loop course where the first half climbs and the second half descends back to the start finish area along the river. The 1:30 pacer kept the pace very steady regardless if going up or down hill. After reaching the high point at about mile 7, I took advantage of the downhill and passed the 1:30 pacer. At this point, the pack surrounding the pacer began to fracture and spread out. Some runners pulled ahead taking advantage downhill. Others fell off the back of the pack yielding to fatigue. Through miles 8 and 9, I felt confident that I would be able to hang on to finish near or below 1:30:00. Each mile split was hit between 6:45 and 6:55. Perfect. Then I hit mile 10 and it was a 7:55 for a total of time of 1:09:20. My 1 minute cushion that I had built up the first 9 miles was gone. It meant I would have to run the next 3.1 miles (5K) close to 20 minutes. Granted my legs were feeling a bit stiff, but I did not think I had slowed that much during the 10th mile. My reaction was to panic and try to pick up the pace as best as I could. Those last 3 miles were grueling. The effort paid off. The finish line finally greeted me with a time of 1:29 and change.
Saint George Half Marathon Start 2020
Choose an Accurate Course and Train to Undershoot your Goal Time
A lesson to learn is train to under shoot your goal time and have a time cushion. Unexpected things happen. The half marathon does not require stops at aid stations to drink or eat. Loosing time drinking and eating is not a factor. But courses change and inaccuracies pop up in unexpected ways.
Another half marathon I ran last summer was a point to point. The bus driver taking runners to the start was also the official starter. The driver had to drive a short ways (.25 miles) past the official start line to park and unload the runners from the bus. He decided to start the race right there where he parked instead of walking back to the official start line. The course was certified and well marked. Every mile split accurately marked and placed. But the actual course became inaccurate (long) because a race official was to lazy to walk down to the official start line and herd all the runners down to the start line and organize them there. This person even joked about it saying runners got even more for their entry fee. Most runners would not agree.
In the case of the Saint George Half Marathon there was a course change involving routing runners around a parking lot instead of right through it as in years past. Not sure if it was marked wrong or was forced on the race organizers to avoid congestion in the parking lot. Neither am I sure if the added distance was shaved off somewhere else to keep the distance accurate. Or perhaps some of the mile markers around this extra loop were not placed accurately. All I know is that suddenly my mile split time slowed from a consistent 6:50 ish to 7:55 for the mile that included the extra loop around the parking lot.
Even the huge Arizona Rock n Roll Half Marathon recently had a course marking mistake that cost some runners an Olympic Marathon Trials qualification.
Mistakes happen. Sometimes course volunteers that are out on the course are not familiar with the actual course and will send runners in the wrong direction. Remember, many volunteers and race officials are not runners and do not have the same mind set towards course accuracy as someone running to achieve a particular goal time. So if you really care about your time and don’t want to make any race day course routing and accuracy mistakes, study and know the course ahead of time. Choose an event that has a reputation for excellence and accuracy.