5 Reasons Not to Use Your Thumb
Firstly we should avoid grabbing without good purpose. Avoiding over-commitment is paramount in good Wing Chun. Excessive use of grabbing can be a crutch that will eventually get kicked out from under you when you run into someone that does not fight your grab but instead uses it to dominate you. That said, when we do grab (such as with a Lop Sau) why should we avoid the use of the thumb?
Examining the case of a Lop Sau, if one pulls an arm using the thumb to grip, the thumb will generally need to come back around the arm before the same hand can be used to strike. This extra motion is not needed if a Lop Sau is performed without the use of the thumb. This is true whether you are using a palm up or more common palm down Lop Sau. The hand can go from holding to striking much faster without this form of over-commitment.
2-When using your hand to grab an opponent’s flesh, the thumb will often get in the way.
What can be grabbed on an opponent to move them? The easy answer is “Anything that fits in the hand.” Guess what? Most of the surface area of the body can be grabbed if you only go for the flesh. Grabbing without the thumb forms a handy self sizing tool that will automatically accommodate most body surfaces your hand lands on and/or the clothing that is in the way. (Marc MacYoung uses the term “gaffing” in some of his writings such as The Secrets of Effective Offense. Picture the hooks used to move fish around. Gaffing gets old real quick with training partners but it should not be forgotten when things are not so friendly.)
The grip between index finger and thumb is not as strong as between index finger and palm. A grip using the thumb may have better 360 degree retention, but does not have the same compression capability. When you are using a Lop Sau, you are controlling he angle of exertion for a split second and escape from the grip should not be much of an issue BUT you do want to be able to exert as much force as a strike through that grip. Our opposable thumbs add great dexterity to our hands but not a lot of brute strength.
4-Sleeves or no Sleeves?
If you are grabbing for someone’s arm to execute a Lop Sau, do they have long sleeves or bare arms? If bare arms then one could use or not use the thumb. If they have big puffy sleeves it would be best to not use the thumb. Sleeves/no sleeves? Thumb/no thumb? BAM!! Too much thinking. You’re hit. The best plan might be to train to use the most versatile option as default. A thumbless grab offers the greatest non-diagnostic approach to grabbing. When not near the edge of fabric (like the lapel of a ju-jitsu gi) the thumb gives little benefit and can actually get in the way of a solid grip on fabric. This reasoning is related to both numbers 3 and 4 above.
5-To reduce likelihood of thumb injuries....both intentional and unintentional.
When grabbing with the thumb, it is rather common for them to be accidentally pried in the wrong direction by an opponents movements. (Pick any direction. If you go far enough, it counts as the wrong direction.) Additionally, if your opponent would like to intentionally bend your thumb in the wrong direction, they become much easier to find by touch if they are being used to grab.
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There are spots where it is not only acceptable but preferred to use the thumb but these are not as common. They include but are not limited to situations involving the use of a Lop Sau at the back of an elbow and situations involving edged weapons. Work out a cost/benefit analysis of thumb use for yourself and then train the way you aim to fight.
Red Light Martial Arts Phoenix