Learn roundhouse, front, side and low kick cleanly: where the force comes from, what you strike with and why the base leg decides every kick.
The honest answer first: four kicks form the foundation of kickboxing — the roundhouse (circular kick), the front kick (straight forward), the side kick (sideways) and the low kick (to the thigh). Master these four cleanly and you have most of the leg game in hand.
And all four live by the same principle: power comes from a kinetic chain from the hip into the foot. The biomechanics are clear — in the roundhouse the segments accelerate one after another, from thigh over shin to the foot, which reaches the highest speed at around 12 m/s. The foot is the whip's tip, the hip the handle.
And this whip packs a punch: across combat-sport kicks the roundhouse reaches peak speeds up to 18 m/s and impact forces into the range of several thousand newtons — numbers that show why technique and control matter so much when kicking. One detail decides both force and precision: your base leg. The more stable and actively bent it is, the harder and more accurately you kick.
Train Smart. Play Hard. — for kicking that means: lift the knee first, then turn the hip, and let the foot whip out last.
The roundhouse is the most important kick in kickboxing. You lift the knee to the side, turn base leg and hip open and whip the shin in an arc into the target. You strike with shin or instep, not the toes. The force comes from hip rotation and the kinetic chain — the foot is only the tip.
The front kick goes straight forward: knee up, thrust the foot forward, strike with the ball of the foot or the heel. It keeps the opponent at distance (the "teep") and disrupts their balance. A fast front kick is like a jab with the leg — it measures and disrupts more than it destroys.
For the side kick you turn sideways and thrust the heel straight into the target. It reaches lower speeds than the roundhouse but delivers the highest impact force of all kicks, because you drive a lot of body mass behind it. It needs practice but is a powerful stopping kick.
The low kick is a roundhouse aimed low at the opponent's thigh. It's allowed in the Low Kick and K-1 styles (not in Full Contact) and extremely effective: a few hard low kicks take away the opponent's stability. Here too: the shin strikes, the hip whips.
On every kick one leg carries you. Keep this base leg slightly bent and stable, the foot turned toward the target. A stiff or collapsing base leg costs you force and balance — it's the single strongest factor for a good kick.
Kicks generate enormous forces — the side kick delivers the highest impact force of all kicks. On a partner that means: always shin guards, always measured. Start every new kick slowly and without force on the bag or in the air before you throw it hard.
Watch your base-leg knee: it should turn along when you kick, not stay rigid — a locked knee under rotation is a classic injury mechanism. And warm up hips and ankles thoroughly before practicing high roundhouse kicks.
Learn each kick in three stages: first lift the knee (the "chamber"), then the extension, last the return. Whoever practices the intermediate raised-knee stage can later feint — from the same raised knee come front, round and side kicks, and the opponent doesn't know until the last moment which is coming.
An often overlooked trick: look at your target but kick "through" it — just like when punching, you accelerate all the way to impact and don't brake before it.
Roundhouse, front kick, side kick and low kick. The roundhouse is the most important and most-used kick, the front kick the easiest for keeping distance. Learn them slowly and one at a time before combining them with punches — technique always before speed.
With the shin or the instep, never the toes. The shin is hard and robust, the toes break easily. The force comes from hip rotation and the kinetic chain into the foot, which reaches peak speeds around 12 m/s.
Because it's your foundation. A stable, actively bent base leg is the single strongest predictor of a kick's force and precision. Pivot the base foot toward the target so the hip can rotate freely — a rigid base leg blocks the power.
Surprisingly not the fast roundhouse but the side kick: it reaches the highest measured impact force of all kicks, because you drive a lot of body mass straight forward. The roundhouse is faster and more flexible to use in return.
Kickboxing: Safety and Injuries