Legal Bowling Actions in Cricket: Chucking Rules and ICC Testing

Cricket law requires the ball to be bowled, not thrown. The distinction matters enormously for the physics of the game — a throw can generate deceptive pace and movement that a bowled delivery cannot. The ICC's elbow extension rule is designed to draw a precise, scientific line between legal and illegal actions.

The Elbow Extension Rule

Under ICC regulations, a delivery is legal if the bowler's elbow extends by no more than 15 degrees between the point when the arm is horizontal and the point of delivery. This margin accommodates natural anatomical variation in carrying angles — some bowlers have arms that appear bent due to bone structure, not throwing mechanics.

What Is 'Chucking'?

Chucking is the informal term for an illegal bowling action where the elbow extends beyond the permitted range during delivery. A bowler who 'chucks' is effectively throwing the ball — using arm extension to add extra pace, spin, or disguise that a true bowling action could not achieve.

The Reporting and Testing Process

1. Match officials observe the suspected delivery and report the bowler to the match referee
2. The match referee notifies the player's national board within 5 working days
3. The board arranges an ICC-accredited biomechanics testing centre assessment
4. High-speed camera analysis measures elbow extension in degrees during the action
5. If extension exceeds 15 degrees, the board must suspend the bowler from bowling in international cricket
6. The bowler may rework their action and be retested — if cleared, they can resume

Can a Bowler Bowl Different Deliveries with Different Actions?

Yes — and this complicates enforcement. A bowler may have a legal action for their stock delivery but exceed 15 degrees when bowling a doosra, carrom ball, or slower delivery. They can be reported for a specific delivery rather than their entire action. Some bowlers have been cleared for their standard off-break but banned from bowling their doosra.

Muttiah Muralitharan of Sri Lanka faced multiple reports due to his highly unorthodox wrist action. Biomechanical testing showed his action was legal — his hypermobile wrist and elbow joint created optical illusion of chucking. He was cleared. Harbhajan Singh underwent testing that cleared him for his standard off-break but raised questions about his doosra.

On-Field Calling of Illegal Deliveries

An on-field umpire can call a no-ball for an illegal delivery immediately if they believe the action is clearly illegal. This is extremely rare in practice — umpires are trained to look for throws but the action happens in milliseconds. Most illegal action issues are reported post-match, not called on the field.

Famous Illegal Action Cases

• Muttiah Muralitharan — most scrutinised bowler in history; cleared multiple times after testing
• Saeed Ajmal — Pakistan spinner banned after 2014 testing showed doosra exceeded 15 degrees
• Shoaib Akhtar — reported but not suspended; used bowling action controversially throughout career
• Sachithra Senanayake — Sri Lanka off-spinner suspended in 2014
• Mohammad Hafeez — banned and cleared multiple times over career

Impact on the Game

The illegal action debate has shaped how cricket polices spin bowling in particular. Doosras and carrom balls are mechanically difficult to bowl with a fully straight arm, which is why so many mystery spinners face scrutiny. The ICC has worked to make the process transparent and science-based, but the inherent subjectivity of optical analysis versus biomechanical data creates ongoing controversy.