Let's be clear from the start, you can absolutely be a good triathlete without ever setting foot in a gym. Swim, bike, run - that's the sport. And if your week is already stretched between the three disciplines, then fitting in strength training probably isn't at the top of the list.

BUT… if you do have the time and the inclination, the evidence is genuinely compelling.

A 2025 randomised controlled trial out of Loughborough University looked at what happened when well-trained male runners added twice-weekly strength training on top of their normal running for ten weeks. What they found was pretty interesting. The strength training group saw their running economy durability improve significantly - meaning they were better at holding their form and efficiency together as fatigue accumulated over a 90-minute run at marathon effort. The endurance-only group saw no such change.

The other finding worth noting? After that 90-minute run, participants were asked to hold a pace close to their VO2 max for as long as they could. The strength training group improved their time to exhaustion by around 35%. That's a meaningful number - the kind of thing that shows up in the back half of a race when everyone around you starts to fade.

And before anyone asks - no, they didn't get bulkier. Lean muscle mass didn't change. The adaptations were largely neural, which is exactly what you'd expect from this kind of heavy, low-rep work.

So what does this actually mean for a triathlete? The run leg of an IRONMAN or a 70.3 is essentially an exercise in fatigue management. How well you hold your economy together after hours of swimming and cycling is often what separates a good run from a great one. Strength training - specifically the kind that targets maximal strength and plyometric qualities - seems to help with exactly that.

So if you're keen to include it but not sure where to start, here's what I'd suggest based on the exercises used in this study and what I use regularly with the athletes I work with.

Plyometrics

These are often underused, or used without enough rest to actually get the benefit. The key with plyometrics is quality over quantity. You want minimal ground contact time and maximum intent on every rep — not fatigue accumulating across sloppy sets.

Pogos — great starting point. Knees relatively straight, working on the ankling action. Three sets of 10–12 reps with 90 seconds rest. Think springy and snappy, not bouncy and heavy.
Drop jumps — a step up from pogos. Step off a box, land, and immediately jump. The goal is that reactive floor contact. Three sets of six reps with 120 seconds rest.
Hop and stick — horizontal plyometrics matter because running is a combination of vertical and horizontal force. Drive off one leg, stick the landing. Express force fast. Three sets of six on each side with 90 seconds rest.
Stiff-leg bounds — another horizontal movement you'll probably recognise as a running drill, and that's no coincidence. Three sets of 10 with 90 seconds rest.

Strength Work

Barbell back squat — my favourite for endurance athletes, and I was glad to see it anchor this study's strength component. The key principle here is heavy and progressive. We're not talking 20 reps at a light weight — that's a different stimulus entirely and doesn't drive the same adaptations. You want to be working at a load where you have maybe two reps in reserve early in the program, closing to one rep in reserve as the weeks go on. Three sets of five to eight reps with two to three minutes rest between sets. Depth should be whatever's appropriate for you — consistent is more important than arbitrary deep.

Seated calf raise (isometric) — don't skip calf work. The soleus in particular is a workhorse for distance running and often overlooked. Load it up, hold maximally for a count of about three seconds, relax, repeat. Four to five sets of four to eight reps with 60–90 seconds rest.

The golden thread through all of it is progression. Just like your running training, these sessions need to get harder over time. Start conservatively, build the load, and give yourself enough rest between sets to actually express quality effort on each one.

If you've been on the fence about whether strength training is worth the time — hopefully this gives you a clearer picture of what it can do and where to start.

If you want to see a great breakdown of this study and exactly how to perform each of these exercises, Dr Kate Baldwin https://www.instagram.com/thedistancedr/ has done an excellent job walking through the full program on her YouTube channel. Well worth a watch: youtu.be/r6hBYimn9s4

Bevan McKinnon / June 2026

LINKS:

Strength Training Improves Running Economy Durability and Fatigued High Intensity Performance in Well-Trained Make Runners: A Randomised Control Trial at https://journals.lww.com/acsm-msse/abstract/2025/07000/strength_training_improves_running_economy.27.aspx

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