Muay Thai Front Teep Kick: Position and Body Angles

Question

What are the angles of the Muay Thai teep kick? I noticed

a) Hip to Knee angle in highest point of chamber is at 45 degrees for the pictures below.

b) Knee to Foot angle: 45 degrees in second and third picture, closer to approx 0 degrees in first picture

c) Also added notes for different leg extension methods and back leans.

Is there a proper guideline, maybe with physics or biomechanics angles, what would be the ideal angle for push teep? Or again does it depend on person's style and individual flavor? I am assuming Ramsey is going for a complete push kick below below, while MuayThaiPros and FightTips is more 'stabpoint-push kick'.

*One thing I did notice after watching Multiple videos of Muay Thai front teep, most athletes stick with the 45-45-30 ratio of Hip to Knee, Knee to Foot, and Back lean.

Note: I came from Taekwondo / karate background where they really work on Kata, and proper angle positioning etc. Muay thai seems to be more 'free style' which is also nice. Watching these gave me a good idea, although all athletes will slightly deviate.

Resources:

Ramsey Dewey

At highest point,
Hip to Knee: 0 to 45
Knee to Foot: close 0 degrees  
Release Extension: Horizontal
Back lean final angle: around 30

MuayThaiPros

Hip to Knee: 0 to 45
Knee to Foot: close 45 degrees
Release Extension: More pendulum, foot ends at highest point where the highest knee elevation was
Back lean final angle: around 30

FightTips

Hip to Knee: 0 to 45
Knee to Foot: close 45 degrees
Release Extension: More pendulum, foot ends at highest point where the highest knee elevation was
Back lean final angle: around 30

Answer 1

The main difference between the fighters in the images you provide is the angle of the torso.

A forward-leaning or vertical torso enables simultaneous defence (and even offence, in the case of Verhoeven, see 01:20). Conversely, leaning back keeps your upper body safer from high counters and, as user Philp Klöcking points out in the comments below, gives your kick greater reach. These benefits can come at the cost of stability if your standing leg is attacked.

Thrusting your hips forward for maximum power also tends to tilt your torso backwards when you're trying to maintain the centre of balance over the standing foot, but a similar degree of power can also be achieved with a vertical torso if you abandon this balance in order to move forward with the kick. The downside to aggressive forward movement is that you become more vulnerable to counters if your kick is caught or evaded or is otherwise ineffective.

What the images do not show is that the shin is typically vertical during the lifting phase. The foot is either angled down, toes towards the ground, which translates into the correct position for a ball-of-the-foot strike during the forward motion, or is held at right angles to the shin, which is better for hard heel strikes (at the cost of reach). A vertical shin also provides for a greater arc of movement, enabling higher velocity to be achieved by the foot at the moment of impact.

Whether or not you desire to execute a snap kick or a push kick, the knee is typically raised to the limit of one's comfortable flexibility before being thrust forward. This results in a roughly 45 degree angle between torso and upper leg. Keeping the leg motion the same for both kicks help makes your intent more difficult to read, although this principle can be discarded if you decide to disguise your strikes. Front kicks can be smuggled in via a roundhouse preparation motion, an axe/circle kick preparation, or even a jumping knee.

How much the leg is bent at the moment of impact depends on how far you are from your opponent. Even if they are close however, it is good practice to thrust your leg towards horizontal, in the same manner as you try to punch 'through' an adversary (if maximum impact is your goal). It's worth remembering though that the longer your leg is extended, the easier it will be for your opponent to trap it, which is never a good feeling, as it typically results in you winding up on the mat.

Samart Payakaroon, provides a good demonstration of the potency of relaxed technique and timing (see 00:33 - 01:30). The whole video, a demonstration of 10 techniques is well worth the watch, but see 05:30 for a demonstration of a front kick disguised as a roundhouse.