5 Essential Swimming Drills for Triathletes to Strengthen Your Core

A woman swimmer streamlines under water at the start of a race.

Written by Maciej Konczewski, Engineer, Swim Instructor, and TriSports Elite Team Member

Having a strong core is extremely important not only for triathletes, but athletes in general. A strong core helps with stability, posture, and overall body control. Furthermore, having a strong core improves how your body functions as a whole. It will not only positively affect your swimming performance, but also aid in your bike and run performance. So without further delay here are my ultimate, favorite swimming drills for building a strong core.

1. Butterfly/Dolphin Kicks
This is not necessarily a drill, but rather a fundamental skill for any swimmer. Any variation of butterfly kicking will take you on your way to building a stronger core. A great way to start with this drill is on your back with fins. It is much easier to keep a tighter core, and a fluid kick this way. Make sure to focus on thrusting your hips and using your body to engage the legs, not the other way around. Work on mastering the body movement and the undulation.

Once you have mastered this you can do various variations:

  1. Without fins on your stomach or back
  2. Kicking on your side
  3. Arms in front of you or on the side

2. Pull Buoy Progressions (thighs, knees, ankles)
This drill is rather simple, but very quickly gets difficult. It is essentially a progression of doing regular pulls with the pull bouy. You start off with the pull bouy between your thighs, and then move it down between your knees and eventually between your ankles. Here are key things to focus on:

  1. Keep your core tight. Do this by squeezing your thighs/legs together as if you were trying to pop a balloon. This will force you to flex your abs and core.
  2. Focus on reaching and stretching your stroke.
  3. Tip: the biggest give away you need to flex your core and squeeze your legs is if you are fish tailing (legs moving side to side).

Bonus: If the pull bouy is too easy, band your legs together with a resistance band.

3. Water Polo & Tarzan Drill
Water Polo swimming, also known as Tarzan Drill, is helpful in two regards. Not only does it help improve your sighting and swimming with your head out of the water, it also works your core and strengthens your neck muscles. This is an essential staple for open water swimmers and triathletes alike. Most of our time is spent training in indoor pools where not swimming in a straight line is extremely difficult, while swimming in the open water is a completely different story.

  1. For beginners, perform this drill in lengths of 25s. This prevents an overly sore neck.
  2. Swim with your head up and out of the water looking forward. Keep your head still.
  3. Arch your lower back to keep your lower half from sinking. This will engage your core. You will need to kick stronger than normal to keep your body balanced and feet from dragging.
  4. Shorten your stroke. It is choppier and quicker than normal.

For newbie tips on sighting in open water, read more here.

4. Extended Streamline off the Wall
This is a simple drill that simply requires you to hold your streamlines longer coming off the wall. It can even be incorporated in your regular sets.

  1. Each time you push off the wall focus on tucking your chin in and stretching your arms tight together behind you head.
  2. Keep your feet and legs flexed and tight throughout the streamline. Challenge yourself to go further each time.

5. Vertical Kicking
This is an extremely effective and simple drill. It requires a deep pool, preferably a diving well, but the deep end of most pools should suffice. This drill not only strengthens your core, but also helps to develop your kick. Start off in the deep end and begin your regular freestyle kick, however, perform it vertically. Try not to help yourself up by using your arms. If this is too difficult use fins.

This drill is good for swimmers of all levels and focuses on the following:

  1. Doing flutter kicks vertically engages your abdominals and allows you to get a feel for the proper motion. This isn’t as easy to achieve swimming horizontally because we often tend to relax our abdominals.
  2. It will smooth out your kick and force you to kick with even more power.
  3. Having a strong kick is what will separate you from the pack.

Bonus: To make this drill more difficult, you can take your hands out of the water. Advance your progressions to place hands on your head or even holding a weight.

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About the Author: Maciej is a swimmer/swim instructor turned triathlete/engineer. Driven by competition and desire to always get faster, and love for the sport. Team Trisports Elite Member who heavily enjoys destination races and seeing new places from the start and finish line, because you have to reward yourself somehow after staring at a wall on the trainer all winter.  Lover of sushi and connoisseur of mac and cheese. He can be found swimming, biking, and running around the suburbs of Chicago. Follow him on twitter/instagram @macheetri