12 weeks Half Ironman Triathlon Base phase

Average Weekly Training Hours 10:29
Training Load By Week
Average Weekly Training Hours 10:29
Training Load By Week

This base training plan is written to prepare you for your Half Ironman Triathlon

1.2 mile Swim | 56 mile Bike | 13.1 mile Run

This base training half ironman triathlon plan will provide you with the foundations of the aerobic training period, which is characterised by increasing volume, performed at relatively low intensities. This phase has a strong emphasis on general conditioning, and physical, mental and technical skills such as working on your swim technique, improving your cycling efficiency, or working on running cadence or technique

This half ironman base plan focuses on the base building phase of training

Reasons for base aerobic training over the winter months

We're going to be going over the physiological adaptations from training aerobically in zones 1 in this article:

Zone 1 Improvements:

Lung capacity and breathing frequency
Stroke volume of heart increases
Cardiac output increases
Heart size increases
Plasma volume expands
Blood flow distribution (shunting)
Heart rate decreases (average)
Inspiratory muscle oxygen cost reduced
Systolic blood pressure reduced
Capillary density increased
Fuel use (favours fat metabolism)
Mitochondrial size and number
Muscle fibre type shifts to type 1
Increase in muscle fibre cross sectional area. Plasma free fatty acid use increases as duration increases

Are you working on all of these areas in your base training period? If not then you could well do with a coach

What are the benefits of training in zone 2 to build your aerobic engine and base fitness?

Zone 2 heart rate power or pace is the intensity that builds aerobic endurance. Go higher than zone 2 and you start to develop anaerobic endurance systems . Go lower than this and you are not working hard enough to challenge the aerobic systems

By the end of the base period you should swim bike and run faster than you did at the start of the base period.

Mark Allen (6x hawaii ironman world champs winner) used a hr as the upper limit of 155 bpm of his running intensity - that's his zone 2! When he first started he was running an 8:15 per mile pace (5:09/ km).

Within a year he was running 5:20 per min mile (3:20 per km) wow! at the same heart rate. He had become 35 per cent faster without working any harder.

This training plan is written to prepare you to finish your first Half Ironman. The weekly volume per week starts at 8 hours and will gradually move up to 12-14. You should already be consistently training 8-10 hours per week before starting this plan and ideally you should have completed some Olympic distance races in the past season

This plan is based on an annual volume of 500 hours per year, which won't necessarily mean an average of 10 hours per week. It will build to 14+ with recovery weeks at around 8 hours per week.

While it’s definitely possible to finish a Half Ironman Triathlon with fewer hours per week or fewer days per week than what you see here, I wanted to present a plan which emphasizes consistent buildup of hours to make your race day more enjoyable and less of a day of Swim-Bike-Walk.
I realize that every athlete has specific strengths, weaknesses, available hours, and other restrictions. Hopefully, you can adjust this plan to fit you well enough.

Sample Day 1

WU: 6 x 50 increasing pace slightly each 25.
MS: All are at T-pace:
100 (10”), 200 (15”), 300 (15”), 400 (30”), 400 (30”), 300 (15”), 200 (15”), 100.
CD: 300 easy with emphasis on form.

Sample Day 1
Cruise Intervals, 3-4x6 minute, heart rate zone 3.

BT: Tempo intervals. Warm up well. Then 3-4 x 6 minutes. Build to zone 3 heart rate. 2 minute recovery interval. Relaxed form! Listen to breathing.

Sample Day 2
Endurance spinning

Use the cadence mode if you have this available. Spin on the high end of your comfortable range in the small chain ring in the 1-2 heart rate zones on a flat to gently rolling course. Allow your feet and legs to relax while spinning. Note and record your average cadence for the ride when done.

Sample Day 3

Warm up with 200m of easy swimming
10x50 alt side kick (25 each side) / free
100 back
10x50 alt Fists + high elbow underwater / free
100 back
10x50 alt catch-up / free
200 easy

Sample Day 3
Work uphills, zones 1-3.

Run a hilly course. Heart rate in zones 2-3 on uphills. Otherwise heart rate in zones 1-2. Avoid heart rate zones 4-5. Take it easy on the downhills.

Sample Day 4
Trainer--spin-ups + dominant leg

Pedaling drill: Do the following 3 times--10 seconds of high rpm, 10 seconds higher, 10 seconds max rpm and then recover for 60 seconds. Then do this 3 times--30 seconds left- and 30 seconds right-leg dominant pedaling (other leg loafs). Repeat all of this 4-5 times. Small chain ring.

Sample Day 5
50% in heart rate zone 2.

Run on a flat to gently rolling course. Get at least 50% of run time with heart rate in zone 2. Avoid zone 3-5 heart rates.

Nick de Meyer
Sound Coaching

Nick has been a Level 3 British Triathlon Coach for 10 years, and has been a master endurance coach with Training Bible Coaching UK in that time. He is also a Training Peaks Level 1 Coach, and was formerly a Regional Development Coach for the South East region for British Triathlon.

Alongside his online coaching business, Nick also runs Speedy Swimming which specialise in 1-2-1 front crawl technique lessons, endless pool swim video analysis, swim clinics and group swim sessions