A man accused of killing a Lichfield factory worker in a drunken attack has denied the assault - telling a jury his false leg prevented him from kicking or stamping with any force.
Carl Keatley, 20, is accused alongside a 16-year-old boy of murdering father-of-five Michael Eccles after spending an afternoon drinking vodka in a park.
Mr Eccles, 43, died on January 26, a day after sustaining serious injuries in an attack just metres from his front door in Lichfield.
The Crown alleges he was "punched and kicked and stamped upon" by Keatley and his co-accused, who cannot be named, as he made his way home from a local convenience store.
Giving evidence at Birmingham Crown Court Keatley, of Greencroft, Lichfield, denied kicking or stamping on Mr Eccles but said he had seen his teenage co-defendant do so.
He told jurors that a prosthetic limb, fitted below the knee of his right leg in January 2007, prevented him from being able to exert any force with his feet. He said: "I am not able to use my feet in a violent way.
"I never did any stamping. I am not able to cause serious injuries because of my leg. There isn't enough force in that leg to cause the damage that was caused to Mr Eccles."
He said the artificial limb also affected his ability to balance and meant that he could not run. Asked to explain why footprints matching the sole of his trainers were found on the back and front of Mr Eccles' shirt after the attack, Keatley said: "I couldn't possibly say."
He told the court he had "tripped over" as his co-accused attacked Mr Eccles, adding: "It could have been an accidental touching of my feet when I fell over."
The teenage defendant had already told jurors he admitted playing a part in the attack but could not remember it because he was drunk.
The teenager, from Lichfield, said: "I wasn't in the right state of mind to know what I was doing."
The boy's father, 55, who also cannot be named, is accused of trying to help his son "cover up" the crime by washing blood from his body and putting his clothes in a washing machine. He denies perverting the course of justice.
The case continues.