This has an accepted answer, so this is purely a supplementary answer.
There are numerous ways to control an opponent's body. Among all of them, only those which employ the neck are potentially lethal.
The reasons are obvious—restriction of breath and potential damage to the spinal cord.
Adding my two cents to very good Steve's answer.
Some additional points for being thigh kicks more dangerous:
calf can be (and usually is) conditioned much better, than thigh.
hitting thigh with your shin is generally better, because your shin is obviously more solid - here you are hitting-soft-with-hardness
hitting thigh injures your opponent's muscles ...
This may require a discussion between the instructor and your son, but try gently incorporating live resistance. A compliant partner just going through the motions of a choreographed sequence will fall at the wave of a hand. But overcoming resistance requires the application of power and technique.
Kicks to the calf aren't generally going to do as much damage as kicks to the thigh. That's because of two reasons: 1) The thigh is less mobile. And 2) The thigh has more mass and is a bigger target.
Most trained fighters will lift up their leg when they see a kick coming to their calf. It's quick and easy to do. But it's not easy to get out of the way of a ...
Taolu (forms) are for a different purpose than Sanda.
Sanda and other forms of "free sparring" are centered on the notion that both opponents are free to move around and fight each other using kicking, punching, and blocks, and occasionally also sweeps, throws, and some standing holds.
Forms are encapsulations of self-defense techniques, or they ...
Modern wushu forms and sanda are basically different styles entirely.
In my now dated experience with wushu competitions, they have many separate events where the overlap between athletes may be close to zero, especially between forms and fighting. This is true in other ways as well; for example, traditional and modern forms events, and almost everyone ...
If one has sufficient vocal training, and can project ones voice, this technique can indeed be used to disrupt the concentration of a many opponents.
Here what I mean is being able to vocalize with sufficient direction and volume that the opponent can feel it in their inner ear. This is particularly effective in a closed space, which creates resonance at ...
Bruce Lee is what I most see.
In the video 1:
At 0:22 the character does Bruce Lee movie vocalization
Although the loose hands are not exclusively from Lee.
At 0:32 the character does Muhammad Ali footwork which Lee was famous for incorporating
At 1:03 the character jumps onto a felled opponent with both heels, which Lee definitely utilized in film