Inmates explain how the programme helps them relax
By Andrew Walker
BBC News, Johannesburg
The prisoners at Groenpunt Maximum Security prison in Free State province are among the most violent in South Africa.
They have raped, murdered, smuggled drugs or abused children. Many are HIV-positive and can expect to die in jail.
Inside prison their anger boils over and violence is common.
But a new programme of yoga lessons is helping inmates to discover ways to calm themselves and take a more positive look at their lives, even if they never get out from behind bars.
From the deck of a rusty old boxing ring Ansuya Khoosal takes the prisoners through a series of yoga positions and breathing exercises.
"Breathe in... And let go," she repeats.
Prisoners say they are more relaxed, and warders agree
The prisoners have their eyes shut, listening to her soothing voice.
They appear at peace with themselves.
"I can't see any smiles!" Ansuya says, and wide, honest grins appear on their faces.
They stand in their bright orange uniforms, flinging their arms up in a flurry of stretches.
Some inmates take it very seriously, others treat it like a bit of a lark, but it is clear that the lessons are popular.
It is the last day of a seven day programme of lessons, teaching the inmates basic yoga positions, as well as breathing exercises devised by yoga master Sri Sri Ravi Shankar.
The organisation that provides the teaching, Art of Living, say they hope the inmates will take what they have learned and practice in their cells on their own.
The organisation cannot run classes every week, but they have identified enthusiastic inmates to carry on encouraging their cell-mates to continue.
A life inside
Maxwell Buthelezi, 24, is in jail for life.
He says he fell in with the wrong crowd at university.
While other students were studying, he was out with his friends, robbing motorists at gunpoint wearing a fake policeman's uniform.
He got deeper and deeper into a gang.
Until one day, he and his friends went to rob a cargo ship they knew was carrying drugs.
But the police were waiting for them.
They suspected one of the gang sold them out, and as the ensuing gun battle with police raged, they brutally murdered him.
"My family is very ashamed of me," he says.
He is two years into his 20-year minimum sentence.
His prison identity card is marked that he is in for life, and can only be released when the Department of Corrections decides.
"This programme has helped me with my anger," he says.
"Just the other day I was talking on the phone and someone was bothering me. Normally I would fight him, but I stopped myself."
"I said to him: 'Listen my brother, what is it that you want me to do?'"
"That night in my cell I felt happy, because I knew I'd dealt with the situation in the right way."
Mrs Khoosal says she has seen a change in the prisoners in just the seven days since she first met them.
"When we arrived they were very suspicious."
"They thought it was an Indian thing, and heckled us, but by the end I could feel they weren't just doing it for the certificate."
The yoga technique she teaches can control emotions, she says.
"When we are angry we breath a certain way and when we are sad we breath another.
"If you can control the breathing, you can therefore control the emotion."
The inmates weren't the only ones who were sceptical.
"When I first heard about it I thought: 'How can that help?'" Anita Hanekom, head of Social Services at the prison told the BBC.
"But now I've seen it can work."
Now the Department of Correctional Services which runs South Africa's prisons wants to implement the programme in other jails.
It has worked in other countries too.
But South Africa's prison system remains a brutal and frightening world.
Many inmates join gangs for protection, and the gangs' influence extends into the world outside where violent crime is rampant.
"We can only hope that they take these techniques with them if they leave prison," says Mrs Khoosal.