When she lifts the weight she keeps her leg extended rather than bending it.
Weight bears down, pushing her leg the wrong way and snapping the bone.
She writhes in agony as a man standing nearby rushes to help her.
This is the excruciating moment a woman snaps her leg bone while at the gym.
The unidentified woman cries in pain as her bone snaps, moments after she lifts a heavy weight using a leg press.
A leg press is a machine used in strength or resistance training. It requires a person to push weight away therefore engaging their leg muscles.
But when the woman she is halfway through her second repetition, having already lifted the weight, she relaxes her leg while it is extended, rather than keeping her knee bent to support the weight.
But the weight is too heavy and bears down on her leg, forcing it to bend the wrong way.
Tom Eastham, a trainer for Push Mind and Body retreat, added that concentrating while lifting weights is key.
He said: ‘You should never relax your legs in a fully extended position due to the risk of hyperextension.
‘If she is using a heavy load, she should be mentally focused at the task in hand, this would ensure her muscles are switched on and functioning properly.
‘Golden rules for the leg press or any other strength based exercises would be: focus, brace then contract.’
This story was adapted from The Daily Mail.