How to engage your core to boost swim speed

Swim coach John Wood shares some swim tips and drills that will help you engage your core and improve your technique, so you glide faster through the water


One of the things that really holds a lot of triathletes back when they swim is dragging themselves through the water. Along with a poor kick, the biggest contributor to this is poor posture. Many coaches, websites and magazines espouse the benefits of doing core strength training as part of a weekly routine, but this won’t automatically make you swim faster. You’ll also need to work on your swim technique.


Use your body’s core muscles to improve swim stroke efficiency

First, try the floating drill, Dead Man’s Float. Hang completely limp and flat in the water; your legs will most likely hang down but this is okay. Then take another deep breath and think about lengthening your spine, engaging your core muscles (think about drawing your belly button up towards your spine), lifting your arms up toward the surface and looking down at the pool bottom.

While doing this, point your toes and you might well find your legs at least starting to rise up toward the surface. Because muscle weighs more than water – and triathletes have more leg muscle than most – your legs might not rise all the way to the surface straight away, but you should feel the benefits of engaging your core and looking down.

Engaging your core will help keep you floating higher in the water – and hopefully minimise the need to rely on your pull buoy. It’ll also help with body roll and take some of the pressure off your shoulders. The less that your shoulders need to do in controlling your movements, the more you can do to propel yourself forward.

Good streamlines off the wall will help remind you to engage your core. Follow a similar idea to the float above when you push off, pulling everything in tight and squeezing your arms tight to your ears. Feel the speed and maintain that strong body position through your first few strokes off the wall.

Core muscle anchors

Your core muscles aren’t just the muscles in your stomach, but include the muscles that surround your spine as well as your glutes. These muscles support the whole of your spine and keep your body upright as well as providing an anchor for your bigger muscles to generate power from.

Work in a straight line

Like any machine, your body works best in one straight line. As a result, when you swim, if your head is high then your hips tend to sit lower in the water. And if you don’t engage your core then there’s likely to be a curve in your spine, so you won’t get as much power from your muscles

Use the long axis

When we swim FC (and backstroke) we rotate along what’s called the long axis (down the spine). Using your core muscles, you can roll the hips and shoulders slightly around this axis to give greater length and control to your stroke. If your core isn’t engaged, you’re more likely to sway side to side.

The session

  Swimsuit/trunks,  hat,  goggles,pull buoy


300m as: 4 x [50m front crawl (FC), 25m backstroke]
100m side kick
4 x 50m as: 25m streamlined kick, 25m swim;  15secs rest between intervals (RI)

4 x 25m steady FC pull, 10secs RI

50m easy backstroke
4 x 50m steady FC, 15secs RI
50m easy backstroke
4 x 100m steady FC pull, 20secs RI
50m easy backstroke
4 x 200m steady FC, 20secs RI
50m easy backstroke

200m of mixed strokes with at least 50m non-FC

Adapt for beginners

Do shorter and fewer reps throughout the main session – go for 4 x 25/4 x 50/4 x 75/4 x 100.

Adapt for advanced


Lengthen the overall reps, do more of each distance, or swim the set slightly harder.