The Thumb-to-Thigh Drill – a great drill focusing on the underwater pull-through of the freestyle swim.
Do you feel like you are swimming endlessly and going nowhere or are you wearing yourself out before completing only one length of the pool? Perhaps you feel like you have reached a plateau, swimming lap after lap, and just can’t seem to get any faster.
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Increasing your Stroke “Distance”
Well, these are all typical frustrations many triathletes experience during the learning stages of swimming freestyle. And the common root of these frustrations is “distance” covered per stroke during a freestyle swim. Now, initially, some of you may think to yourselves…”I just need to learn to swim faster!”
And, the natural remedy would be to include speed or quality training to your regimen to help boost your overall speed. However, before I ever recommend any speed work training, I first like to assess the swimmers freestyle stroke to determine if technique is the main culprit. And in doing so, I initially focus on the swimmer’s underwater pull-through (taking into consideration their body position and kick are adequate). A proper underwater pull-through is crucial to the freestyle stroke and is a key component for initiating and maintaining forward momentum.
Incomplete Follow Through Underwater
And it is here, that I often notice one of the most common mistakes a new swimmer encounters when swimming freestyle. And that is an incomplete pull-through during the underwater portion of the arm stroke. In other words, the swimmer is not extending the arm behind him/her at the end of the underwater pull-through.
Initially, a swimmer will start out swimming the first few strokes of freestyle correctly. However, with each stroke, fatigue sets in as the tricep muscles begin to tighten and the underwater pull through is shortened. Rather than extending the arm all the way through during this portion of the stroke, the swimmer will lift the elbow out of the water too soon in an effort to get the arm(s) out and around for the recovery.
Consequently, the swimmer is “grabbing” less water during the underwater pull-through as the number of strokes he/she takes increases. And typically, the arm strokes become hurried and choppy. And this is where bad habits begin. Especially for someone swimming solo with no way of knowing if such habits even exist.
Some Examples
Refer to Figure 1. At Point A you will see an example of a swimmer who is lifting the elbow too soon out of the water and not pulling all the way through during the underwater portion of the stroke. By doing this, the swimmer has sacrificed valuable forward momentum by not extending the arm behind him/her. This will result in less distance covered per stroke and more strokes taken over a given distance and even more importantly, more energy wasted.

Now, take a look at Figure 2. At Point B, you can see the swimmer has continued the pull through underwater by extending the arm behind him/her. This not only moves the swimmer forward farther per stroke, it also reduces the number of strokes the swimmer will take over a given distance. Fewer strokes means less energy spent. And less energy spent per stroke equals greater endurance allowing you to build your swim distances quicker and easier.

The Thumb-to-Thigh drill is an excellent drill to help facilitate a proper and complete underwater pull-through.
How to Do The Drill
To begin, stand upright on a flat surface, feet about 4-6 inches apart. Drop your arms by your side and mentally mark where your thumbs naturally line up with each thigh. Once swimming freestyle, you want to lightly drag your thumb across this spot during the underwater pull-through.
This will insure that your arm is extending behind you (refer to swimmer in figure 2). Very simply, this drill taps into your muscle memory. You want to get used to pulling all the way through extending the arm behind you. Initially, this drill may be difficult or tiresome probably because your tricep muscles are weaker than you thought! However, with some strength work and practice, you will begin to develop a feel for this drill and enjoy the positive results that will follow.
This is also a good drill to maintain throughout the season, for no matter how good of shape you are in, your arms will inevitably get tired during your swim training and this is where bad habits are introduced. I also recommend adding some tricep work during your dry land/weight workouts.
Sample Practice Set
10 x 25’s freestyle working on Thumb-to-Thigh, 15 seconds rest between each. Adjust your rest accordingly.
View any of the other four drills below:
Thumb to Thigh
Touch and Go (aka Catch-up Stroke)
Closed Fist
Balance and Rotation