How to run a Sub 90 Half Marathon

3 min read

This article shares how I ran a Sub 90 Half Marathon and the steps taken to achieve it.

Hopefully, by sharing my experience, it will be of value and help your running too.


To run a Sub 90 Half Marathon (in less than 1 hour 30 mins), you need to run 13.1 miles (21.1km) at an average pace of 4:15 min/km or 6:51 min/mile.

Successful Sub 90

On Sunday 4th April 2021, I ran a solo Half Marathon Sub 90 in 01:28.21 – View the Strava activity here.


Training Plan: Ben Parkes Half Marathon Advanced Level 4 Plan

The following screenshot was taken from my Strava account training log, showing the 12 weeks leading up to race day:

Sub 90 Half Marathon - Training Plan


During the plan, I trained to a target HM Goal Pace of 4:12/km (slightly faster than the 4:15/km required for Sub 90). This was beneficial as my body got used to running regularly at that pace and when it came to race day, 4:14/km and 4:15/km felt a lot more cruisy and comfortable.

In previous races, I adopted a negative splits approach to racing, with success.

However, in the lead up to this Sub 90 Half attempt, I achieved a 10K PB whilst aiming to maintain my Half Marathon Goal Pace for the whole 10K.

It got me thinking that previously I may have been selling myself short by running the first 5K of the Half Marathon, 30s – 15s slower than the goal pace.

This time, I looked to go for even splits and ease into my goal pace from the first mile but being careful not to go off too fast.

Watch Setup

One of the biggest successes on race day, was the use of Avg Pace field on my Garmin watch face.

Normally, I would use Last Lap Pace in field 3, however the average pace for the whole race rather than just the last km would be more valuable for a Sub 90 attempt.

The following fields were used in the race instead:

Field 1: Timer
Field 2: Lap Pace
Field 3: Avg Pace
Field 4: Distance

I knew that a minimum average pace of 4:15/km was required, so the Avg Pace field allowed me know how I was doing towards the end goal at any point in the race.

Race Day Splits

I managed to keep each km fairly consistent throughout the race. As I reached the final 3km, I was confident that Sub 90 was safe (4:13/km avg pace at that stage). So I opened up the stride and pushed harder to finish strong.

My final average pace for the race was 4:11/km.

Previous Failed Sub 90 Attempt

My successful Sub 90 Half Marathon was a second attempt at the achivement.

Almost exactly a year earlier in April 2020, my first attempt was unsuccessful (1:37 – view this activity on Strava).

On reflection, I was unsuccessful first time around because I ran untapered during a marathon training block. It followed a peak training week (100km) and my legs were heavily fatigued, so there was no power.

My training was focused towards the Marathon, so I had been regularly running much slower, than the required goal pace to achieve a Sub 90 Half.

The experience of this failed attempt was valuable because it informed my approach, as I applied the lessons learnt to the second Sub 90 Half Marathon attempt and do things differently.

Marginal Gains

The following are all extra 1% marginal gains that helped to improve my running during the training block:

Drills & Strides

I used drills after a Warm Up and before Strides, to help improve my running form and speed. I found the following YouTube video on Drills particularly helpful:

Strength Training

The training plan included a weekly strength training session (10 in total), which significantly helped with injury prevention and core strength. It helped the body cope with the increased load and demands of training. Allowing for the consistency necessary to achieve the goal.

Race Day Fueling

3 hours before the race, I used Maurten 320 Drink Mix to ensure my body was primed and fully loaded with carbohydrates.

Most people don’t need to take gels during a Half Marathon, but I did take an extra Maurten 320 Drink Mix with me and added to my water on the Time Trial course.

Studies have shown that our bodies can make use of up to 90 grams of carbohydrates per hour. One Drink Mix 320 sachet, mixed with 500 ml of water – contains 80 grams of carbohydrates.


To aid recovery during the training plan, immediately after a session, I had a pre-prepared recovery smoothie, containing the following ingredients:


Something that shouldn’t be overlooked is the help and support of others in the running community.

Firstly, @myeverydaytempo and @aldridge_runner, who have both been concurrently training for a half marathon, using the same L4 plan. It is great to share the same training experience, supporting each other as you work towards a common goal.

I’ve been inspired and received sound advice from peers & creators in the community, including @themarathonmarcus, @amritpalghatora, @fodrunner, @benparkes, @thebuggycoach and @northeastprojectrun.

Thank you.

Buggy Running

Just before the start of the training plan, my son, George, became 6 months old, meaning we could begin buggy running together.

George became my training partner and joined me on easy runs throughout the three months of the plan.

This was, without doubt, my favourite and most enjoyable part of training.

The highlight was sharing a 24K long run together, the longest run on the plan. The weather was warm & sunny, we paused half way for a quick snack and to watch the ducks. A very special day.

There are literally no drawbacks to buggy running. You get free resistance added to your training, building strength, as you create and share special memories together. Whilst giving Mum a well earned break too.

Final Thoughts

Celebrate the outcome but treasure the true value in the process and special memories made along the way.