There is a Kona age group finisher athlete called Bojan Djuric who I truly admire. He’s sitting in the 45-49 category, and I’m just amazed by his fitness condition regarding his age, and considering the fact he’s declaring not doing any particular core strength session !
It’s very unfortunate, but I don’t have that luck, and I had to work a lot in this area to get a body capable of handling the training stress of an IronMan 140.6 without getting injured. Basically lack of strength means that the key parts of your body like bones and joints will be stressed beyond what their intended purposes and skills are, leading to inevitable injuries, some of them lasting sometimes for years, if not for life. It’s plain stupid when you consider that with a bit of work it can easily be avoided.
Even the greatest of all runners, Eliud Kipchoge, acknowledged the power of core strength training and has [implemented some] into his training in the past few months. When done properly, it will allow you to increase and improve your intermuscular and intramuscular coordination — something that can make a huge difference in the long run.
How much time you should spend on core strength is highly dependent on your weakness and the time left you still have to dedicate for it in your schedule. During my season, I would say there were two distinct phases, the first and longer one that lasted from September 2018 to May 2019 where I was doing 2 hours — 2 x 30 minutes, 1 x 60 minutes — a week and then from June 2019 to September 2019 with only 1 hour — 2 x 30 minutes — a week. I removed 1 hour of the schedule because my fitness form was really at a peak, and the benefits of that extra hour were at that point really marginal.
Throughout the whole year, my core strength routine remained exactly the same though, and was focused on my back, neck, and legs. You will find below all the exercises I was doing and the reps associated, based on 3 laps per 30-minute session. All were done in that particular order.
TRX Push ups
Using a TRX for the legs, doing 15 reps.
Kettlebell swings
Using a 16 kilos weight, doing 15 reps.
Single leg squats
Using a chair, you should ideally just touch it and then sit up straight, doing 10 reps per leg.
Plank
Keeping it for 60 seconds, doing 1 rep.
Crunches abs
The classic one, doing 15 reps.
Left lateral plank
Keeping it for 30 seconds, doing 1 rep.
Leg lifts with dumbbell
Using a 3 kilos dumbbell, doing 15 reps.
Right lateral plank
Keeping it for 30 seconds, doing 1 rep.
Wheel abs
Probably the most challenging abs exercise, doing 10 to 15 reps.
Lunges
Using 10-kilo dumbbell for each arm, doing 10 reps per leg.
Basically, doing one lap with all these exercises was taking me around 12 minutes. I was taking one-minute rest between each of the 3 laps to just get some water before starting it all over again.