Shins break after a defender checks a kick due to a combination of impact force, bone stress, and improper striking technique. Here’s a breakdown of why it happens:
1. Bone-on-Bone Impact
- When defenders properly check a kick, they raise their shin and angle it so the hardest part of their tibia (the upper part, near the knee) absorbs the impact.
- If the kicker lands their strike on the lower part of their tibia (closer to the ankle or mid-shin), which is thinner and weaker, it can fracture on impact.
2. Structural Weakness & Stress Fractures
- Fighters who haven’t conditioned their shins properly may have weaker bones that are more prone to breaking.
- Repeated stress from training and previous microfractures (small bone cracks from repeated impact) weaken the tibia over time, making it vulnerable to a full break.
3. Improper Kicking Mechanics
- If the kicker doesn’t properly rotate their hip and drive the kick through the target, they may land on the wrong part of the shin, increasing the risk of injury.
- Kicking with the lower shin instead of the upper shin increases the risk of fractures.
4. Angle of the Check
- A well-executed check exposes the stronger part of the defender’s shin while presenting a hard, stable wall for the kick to crash into.
- If the check is angled outward, the kicker’s shin hits at an awkward position, increasing the likelihood of snapping.
5. Timing & Force Multiplication
- If the kicker is fully committed to the kick and the defender times the check perfectly, the kicker’s full momentum works against them.
- The defender’s shin acts like a steel rod, stopping the kicker’s force abruptly, creating a high-impact collision that results in a break.
Famous Examples
- Anderson Silva vs. Chris Weidman (UFC 168) – Silva threw a hard leg kick, and Weidman checked it perfectly, causing Silva’s shin to snap.
- Chris Weidman vs. Uriah Hall (UFC 261) – Ironically, years later, Weidman suffered the same injury when Hall checked his kick.