Kenyan grandmothers learn self-defence – in pictures

Wairimu Gachenga waits her turn to practise self-defence techniques in the Nairobi slum of Korogocho. Since 2007, older women in the slum have been getting together once a week to practise self-defence techniques after one of then was raped Photograph: Karel Prinsloo

Gachenga pummels a punchbag. Rape of elderly women has increased in Kenya as some people believe they are less likely to carry HIV Photograph: Karel Prinsloo

Gachenga adopts a defensive stance. The classes also work as a support group for local women, where they can swap stories and check everybody is OK. If one of the members does not show up, they know that something is wrong Photograph: Karel Prinsloo

Outside of self-defence classes, Gachenga looks after her grandchildren, preparing breakfast while her granddaughter completes homework. Women of all ages who live in slums are at risk of sexual violence, often in communal sanitation facilities Photograph: Karel Prinsloo

Gachenga bathes after preparing breakfast for her grandson, Wahome Njeri. A study by Stanford School of Medicine has found that among girls, too, the teaching of self-defence can dramatically reduce vulnerability to sexual assault Photograph: Karel Prinsloo

In an attempt to make ends meet, Gachenga collects plastic and other recyclable material from the Dandora rubbish dump, one of Africa's largest Photograph: Karel Prinsloo

Gachenga carries a bag of recycling material. She receives vegetables once a week from a local church Photograph: Karel Prinsloo

Gachenga shows the 30 Kenyan shillings (about 23p) she earned for her recycling Photograph: Karel Prinsloo