The physics in plain English
Momentum equals mass times velocity. When two players collide in a tackle, the player with more momentum — not more weight — wins the collision. A 90kg flanker sprinting at 8 m/s has 720 kg·m/s of momentum. A 115kg prop jogging at 5 m/s has only 575 kg·m/s. The flanker wins. This is why closing speed and body position matter more than the number on the scale.
1,600-2,500 N
Average tackle force
Measured at professional level
10-25
Tackles per match (forward)
Front row and back row
4-12
Tackles per match (back)
Depending on defensive system
Why smaller players can dominate tackles
Three factors give smaller players an advantage: (1) lower centre of gravity means better leverage — getting under the ball carrier is the single most important tackle technique, (2) faster closing speed generates more momentum, and (3) leg drive after contact is where tackles are won or lost, and this is pure relative strength and technique, not body mass.
The 4 keys to a dominant tackle
- Body height — get low before contact. Your shoulder should hit between the ball carrier's hip and ribcage. The lower you are, the more leverage you have.
- Timing and foot placement — plant your lead foot as close to the ball carrier as possible. If your feet are too far away, you are pushing at an angle and losing force.
- Leg drive — the tackle is not over at contact. Drive your legs through the tackle for 3-5 steps. This is what separates a dominant tackle from a passive arm tackle.
- Arm wrap and squeeze — your arms lock around the ball carrier and squeeze inward. This controls the descent and can dislodge the ball.
Tackle types and when to use them
| Tackle type | When to use | Key focus |
|---|---|---|
| Front-on dominant | Ball carrier running straight at you | Low body, leg drive, head placement |
| Side-on / drift | Ball carrier running across the field | Timing, shoulder contact, roll to ground |
| Chop / ankle | Last-ditch, covering tackles | Hit below the knee, arm wrap immediately |
| Double / assist | Organised defensive line | First tackler goes low, second controls ball |
| Smother | Close-range, ball carrier receiving pass | Drive through before they can offload |
Gym exercises that improve tackle power
- Trap bar deadlift — mimics the low body, leg drive position of a tackle
- Power clean — explosive triple extension (ankles, knees, hips) transfers to tackle impact
- Sled push — the closest gym exercise to sustained leg drive through contact
- Single-leg squat / split squat — tackles are initiated from a single-leg stance
- Neck and shoulder strengthening — protects against injury and improves force transfer