Should triathletes strength train?

In Australia, researchers split 25 long-distance triathletes into two groups for 26 weeks. Both groups kept their usual training. Fourteen of them also lifted weights. They lifted moderate loads for 12 weeks, then heavy ones. Three times during the study, everyone raced a test triathlon in the lab. It was a 1,500-metre swim, a 60-minute ride and a 20-minute run.

The lifters rode more economically by week 14, and ran more economically by week 26. Economical means the same speed costs you less oxygen. The triathletes who did not lift did not change. And the lifters weighed the same at the end.

An older study in France found the same on the run. Fifteen triathletes trained the same way for 14 weeks. Some of them also did two heavy weight sessions a week. At the end, they were stronger and ran more economically than the ones who did not lift.

The lifters in these trials used barbells and machines, because those are easy to measure in a lab. What counts is the heavy load, not the machine.

In the water, the gain is smaller. A review of 27 studies in swimmers found strength work made them about 2 to 2.5 percent faster. Your stroke is still learned in the water, as our Note on dry-land drills explains.

A triathlon is long, and the run comes last. So what matters is how you hold up late in the day.

In Norway, 19 well-trained women who raced duathlons were split into two groups. A duathlon is a run, a ride, then another run. For 11 weeks, 11 of them added heavy leg lifting twice a week. Then each woman rode for three hours and finished with five minutes all out. The lifters held 7 percent more power in those five minutes. After 90 minutes of running, their five all-out minutes improved by almost 5 percent. The women who did not lift did not change.

Every stride of a run lands on your tendons, the cords that tie muscle to bone. In Germany, 18 well-trained triathletes were split into two groups. For 12 weeks, one group added heavy strength work three times a week. Their Achilles tendons got 39 percent stiffer, and their squat got 20 percent stronger. Stiffer means the tendon stretches less under the same pull. They kept all their usual endurance training too.

That study measured tendons, not injuries. For injuries, look across sports. A review pooled 25 trials of exercise programmes. In the trials of strength programmes, injuries fell to less than a third.

Time is the reason most triathletes give for skipping it. In a survey of 390 long-distance triathletes, about half did no strength work. Of those, 53 percent said they had no time. The triathletes in that survey trained about 15 hours a week. None of the trials here tested a week as short as yours.

But the sessions can be short. In one study, 21 young men trained twice a week for six weeks. Some did 12 minutes of kettlebell swings. The others did jump squats. Both groups gained almost 10 percent in squat strength and almost 20 in their jump.

And once you have built it, it lasts on less. In Norway, cyclists lifted twice a week for 12 weeks. In their race season, one session a week kept what they had built. Only six cyclists lifted in that study, so it is a small one.

So spend your spare hour on short strength sessions. Your swims, rides and runs already build your engine. Nothing in them is heavy.

Light weights lifted many times are more endurance work. You get plenty of that already. Strength comes from a heavy load, so heavy that a few reps are all you have. Or it comes from a movement done as fast as you can.

Twice a week, do slow, heavy work. In a heels-elevated squat, you hold a bell at your chest. Take three seconds to go down and hold three at the bottom, for five reps. Rest until you feel fresh, then go again. In a get-up, you hold a bell over your head and keep the rest of you steady. That is posture held under a load.

On other fresh days, do a few fast sets. In a swing, drive the bell with a snap of your hips. Stop each set while every rep is still fast.

The first few sessions will leave your legs sore. In one study, a first bout of heavy lowering work left the thigh at 86 percent of its strength two days later. Two weeks on, the same work barely dented it.

The slow, heavy work can take the morning after a threshold, VO₂max or long session. Never put it on the same day as one, or the day before. How to schedule strength around endurance explains why. Why endurance training alone never builds this strength is in Strength makes endurance cheaper.