The 1.9km swim at the start of a half Ironman/middle distance triathlon hits that tricky not-so-sweet spot. It’s long enough that you need a solid base of endurance. But short enough that, if you want to be coming out with the front pack in your age group, you need to be able to hold speed. And getting the balance right in training to see improvements can be difficult to master.

Expert swim coach Lucas David, a National Champion swimmer himself who works with everyone from elite level swimmers and triathletes to age-groupers, gives us his top tips for improving your speed and your endurance in the water.

Training focus for half Ironman swim speed: get fast, then train yourself to hold pace

With pool time limited, and public lane sessions often being chaotic at best. It can be easy to fall into the trap of swim training without any specificity. Many age-group triathletes make the mistake of either only ever swimming easy (which is great for endurance, but won’t help you get faster). Or conversely, hopping in the water and smashing out a set of fast 25s and 50s because – let’s face it – that’s way more fun than ploughing up and down in the lane. Which will give you a good bit of short distance pace, but won’t help you when you’re exhausted before you even hit the first turn buoy on race day.

Like the bike and run training for a half distance triathlon, you’ve got to get that balance of speed and endurance nailed for optimal performance. “If you want to get quicker over the 1.9km swim distance, you need to cycle between threshold work and building your endurance engine,” says Coach Lucas. “It’s great to be in shape. But let’s say you want to hold 1:30/100m pace on race day, but you’ve never swum quicker than 1:35/100. Hitting that target race pace is going to be incredibly difficult!”

“Start with threshold work to get fast first, and then train yourself to hold that pace over longer distances.”

Example swim workout to boost your half Ironman swim speed

Below you’ll find an example swim set from Lucas which is tough, but an ideal way to get your body to tolerate holding a higher swim pace for longer.

Make sure your open water swim training has structure and purpose

Plenty of us are guilty of ticking off a full winter of structured pool swim sets. Only to get in open water and swim aimlessly around at the same easy pace. Which is fun – but isn’t necessarily the best approach if you want to be able to swim fast on race day!

This is why, Lucas says, it’s important to approach your open water swimming sessions with the same focus, structure and purpose that you take to the pool. “How you train is how you race. Anyone can do volume, but open water time is often rare and incredibly valuable. So we need to be as race specific as possible!”

Stay tuned for more swimming tips

In the coming months we’ll be bringing you more swim content, including pool and open water swim sets – so stay tuned. Sign up below to be kept in the loop…