A Good Torpedo Body Will Sink
A good torpedo streamline helps develop your swimming technique. This is why every swimmer and triathlete should excel at this – regardless of whether they are beginners, intermediate, or advanced swimmers.

Before we explain why, here's how to maintain the torpedo position:
-Align one hand with the other. The top thumb grips the bottom hand.
-Keep your hands in this position, extending up to the head. Ideally, you should be able to place your arms behind your head – if you're flexible enough, you can maintain a straight line in the water, with minimal resistance.
-Next, squeeze your shoulder blades together to tighten your arms as much as possible.
This is how elite swimmers use it – very fast speed. You'll feel a stretch in your arms and shoulders, through your core. You must extend your core, making this position upright and tall – this is a good habit, so you should do it fully.
A streamlined position has very low resistance, under the powerful pushing of your legs, allowing you to exit the wall very quickly. At approximately 50-60 centimeters below the surface, move for the first stroke, then break the surface. If you do it right, you should cover at least five meters. If your pool has markers, these are 5m from the edge, so they can be used as a reference. Remember: the first stroke is after the flag!
Now, if you're an Ironman triathlete competing only in open water, why do you do torpedo training?:
1) The extended position reminds you this is the correct way to swim – being straight in the water. Re-focus on each lap.
2) You leave the wall at this position at a very fast speed (likely twice your normal swimming speed), with the water flow and sensation around your body allowing you to sense high-speed swimming.
3) For the first few strokes, your movement speed will be faster than usual. This is a valuable experience for you – try and maintain this speed as long as possible.
4) A good torpedo streamline will develop and maintain flexibility in your upper body. You will do 40 to 100 torpedoes each, with each torpedo stretching your chest and shoulders. Over time, this can have a huge impact on your body's range of motion, so you can have better swimming technique.
5) If you get lazy stretching your arms and legs while torpedoing, you might do it during the full swim. Good swimming technique starts with the torpedo.
6) Finally, but not least, a fast torpedo streamline means you'll swim faster in the pool.