Kicking Programme — Style Does Not Decide Force
The only controlled measurement found no significant force difference between systems. A programme that draws the consequence.
Contents
What this programme is for
Almost every kicking programme promises the same thing: a harder kick. The article The Roundhouse Kick Compared shows there is no basis for that — and that is exactly the starting point here.
As with the other programmes in this series: a programme is a recommendation, not a finding. Where a figure below comes from a study, it is named; everything else is reasoned choice and says so.
The negative finding
Gavagan and Sayers (2017) measured 24 advanced practitioners — eight per discipline — under identical laboratory conditions: motion capture with nine cameras at 500 Hz, force measurement at 1000 Hz.
| Measure | Muay Thai | Karate | Taekwondo |
|---|---|---|---|
| Execution time | 1.02 ± 0.15 s | no sig. difference | 1.54 ± 0.52 s |
| Max. knee extension velocity | −706 ± 200 °/s | −947 ± 94 °/s | −943 ± 106 °/s |
| Vertical velocity of centre of mass | 1.24 ± 0.15 m/s | 0.78 ± 0.24 m/s | 0.93 ± 0.19 m/s |
| Impact force | 1400 ± 419 N | 1211 ± 219 N | 1547 ± 530 N |
The force difference is not secured: P = 0.281. The spreads are larger than the gaps between the means — and the highest mean went to taekwondo, not Muay Thai.
Build a programme on “more force through style X” and you build on something that has not been measured. What is secured: Muay Thai’s shorter execution time (P = 0.028), its slower knee extension (P = 0.010 / 0.011) and its markedly larger centre-of-mass movement (P = 0.001 / 0.02). A programme can be built from that — just not the usual one.
The finding that inverts the goal
And now the sentence that contradicts the commonest training emphasis:
Gavagan and Sayers found similar maximum pelvic rotation velocities in all three groups.
Hip rotation is the single strongest factor for effect — but it is not a distinguishing feature. All three expert groups rotate the hip at roughly the same speed. The difference lies in what happens next: Muay Thai lets the rotation run on; taekwondo and karate add knee extension on top.
Hence the structure:
- Hip rotation is the shared foundation, not the edge — phase 1, for everyone.
- After that there are two engines, and you choose one per kick. Mixing them is why many kicks feel weak: half a rotation plus half an extension gives neither.
Phase 1 · Weeks 1–4 — the shared foundation
Rule: in this phase nothing is kicked against resistance. No bag, no shield, no pad.
| Exercise | Volume | Criterion |
|---|---|---|
| Hip opener without a kick — support leg pivots, pelvis rotates to its limit, leg stays folded | 3 × 8 per side | at the end the navel points beyond the target |
| Sequence drill at the wall — support leg → pelvis → thigh → shin, four separate moments | 3 × 6 per side | each of the four steps can be halted on its own |
| Centre-of-mass work — the kick comes from the whole body falling in, not from the leg | 3 × 6 per side | you land displaced, not on the starting spot |
The centre-of-mass work has the clearest number behind it: 1.24 m/s against 0.78 and 0.93 — the largest relative difference in the whole study, and highly significant.
On to phase 2 when: full pelvic rotation without help from the arms · the four sequence steps halted individually, both sides · no knee pain after pivoting (if there is, build the knee work first).
Phase 2 · Weeks 5–8 — choose the engine
Rule: one engine per kick. Not both at once.
| Engine A · Whip | Engine B · Extension on top | |
|---|---|---|
| Measurements | knee extension −706 °/s, largest CoM movement, shortest time (1.02 s) | knee extension −947 / −943 °/s, smaller CoM movement |
| Support leg | pivots fully | pivots less, stays stable |
| Knee | not actively extended; it opens through the rotation | actively and quickly extended |
| Body | falls into the kick | stays upright over the support leg |
| Striking surface | shin | instep or ball of the foot |
| Criterion | the body runs on; you land displaced | the leg returns along the path it went out on |
| Commonest fault | adding knee extension — it brakes the rotation | letting the body fall in — it robs the extension of its base |
Volume for both: 4 × 8 per side, technique before speed.
Against expectation: engine A is the faster one, not the slower. The formula “the Thai kick is slower but stronger” is unsupported in both halves — slower it was not, and stronger is not secured.
Why not both: a kick has only one moment at which it arrives. If the rotation is still running and the knee extends, two accelerations reach the same target at different moments. That is an assessment of the measurements, not a measured finding — nobody has measured mixed kicks. As a rule it serves, because it forces a clear decision.
Phase 3 · Weeks 9–12 — the striking surface and what it obliges
The review in Healthcare (14(4): 430, 2026, 23 studies analysed) names three technical determinants — and they are the same three for effect and for injury risk:
| Decision | Effect | Risk that comes with it |
|---|---|---|
| Support leg pivots | frees the hip, full rotation | cruciate ligament, meniscus |
| Striking surface shin | maximum impulse transfer | tibial contusion, periosteal irritation, stress fracture |
| Striking surface instep | higher speed, more reach | metatarsal fracture, ankle |
That is the design rule: each decision brings its own preparation. Not an add-on, but part of the technical decision.
Shin track — build over the full four weeks, no faster: week 9 soft padding, weeks 10–11 Thai shield, week 12 bag. A stress fracture does not come from one hard kick but from many in too short a time. Stop on pressure pain at the front edge of the tibia that persists overnight — then at least a week with no shin contact; pain at the same spot for more than two weeks should be examined, because stress fractures are often invisible on early X-rays. What does not help: “toughening” shins with bottles or sticks. What adapts the structure is dosed loading over months.
Instep and ball-of-foot track — no instep kick into hard targets with edges; ankle extended and fixed, since a soft ankle at impact is the mechanism by which metatarsals break.
| If you … | then permanently |
|---|---|
| pivot | single-leg squats, landings with rotation, hip abductors |
| strike with the shin | slow load progression, calf strengthening, keep the rest days |
| strike with the instep | ankle stability, toe flexors, balance on unstable ground |
What here is choice and not finding
- Twelve weeks, the phases and all repetition counts are convention. No study sets kicking volumes against one another.
- “One engine per kick” follows plausibly from the measurements but has not been surveyed.
- The conditioning progressions come from practice, not from studies.
- Force is not damage. A load cell measures peak force in newtons. What destroys a leg is impulse — force over time — and that was not measured.
- Eight people per group. At that sample size a difference has to be very large to reach significance. “Not demonstrated” does not mean “not present” — including for the force difference.
- And the programme is untested. Derived, not set against another.
A fuller version with fault patterns, progressions and the full reasoning behind each prescription is in preparation as a companion.
Related Articles
- The Roundhouse Kick Compared
- Breathing Programme
- Muay Thai
- Taekwondo
- Kyokushin Karate
- Sanda
- Footwork Programme — the counterpart without a measured basis: the same legs, different rules of honesty