Summary
A bowler's arm can flex up to 15 degrees during delivery. Beyond this, the action is deemed illegal (throwing/chucking). This rule resolved the Murali controversy.
Full Explanation
The 15-degree rule was introduced in 2004 after extensive biomechanical research prompted by the Muttiah Muralitharan chucking controversy.
Before 2004, the rules stated a bowler must not 'straighten' their arm during delivery, but this was subjective and led to inconsistent enforcement. Research found that virtually all bowlers have some degree of elbow extension during delivery — many were unknowingly exceeding what was considered legal.
Key findings from the ICC's biomechanical studies: - Average elbow extension for pace bowlers: ~8 degrees - Average for spinners: ~10 degrees - Muralitharan's extension: ~10-14 degrees (within 15-degree limit) - The human eye cannot detect flexion under ~15 degrees
The process for suspected actions: 1. Match officials or opposing captain report a suspect action 2. The bowler is tested in a biomechanical lab 3. If they exceed 15 degrees, they are suspended from bowling 4. They can be retested after remedial work
Several prominent bowlers have been reported and tested, including Sunil Narine, Saeed Ajmal, and Mohammad Hafeez. Ajmal was effectively forced into retirement after being unable to remodel his action within the limit.
Key Points
- •15-degree elbow flexion limit for all bowlers
- •Introduced in 2004 after Murali chucking controversy
- •Research showed all bowlers have some arm flexion
- •Process: report → testing → suspension if over limit → remedial work
- •Saeed Ajmal's career effectively ended by this rule
- •Sunil Narine reported and cleared multiple times
Notable Controversies
- •Muttiah Muralitharan no-balled by Darrell Hair (1995) — eventually vindicated by the rule
- •Saeed Ajmal effectively retired after failing to remodel his doosra within 15 degrees
- •Sunil Narine repeatedly reported and suspended in IPL/international cricket
- •Mohammad Hafeez reported multiple times