Mainly that was because, tonight, unusually, she was here alone, but also because she was an absolute knockout. He’d been watching her for at least a couple of months now. She was a frequent attendee at the gym, and she worked hard when she was here, often pushing herself close to the limit, and fuck, did it show.

She was about nineteen, he reckoned, and though, up close, there was something vaguely wintry about her, she was still an absolute beaut, with a porcelain-pale complexion, a pink, cherubic mouth and piercing blue eyes. Her hair wasn’t red as such but fair with reddish tints; it was also short, spiky and shaved at the back and sides, a near-punk look, which, along with her trim but terrific physique, and her little shorts and sweat-damp vest, only added to the ‘action girl’ lustre.

Truth be told, Nathan was no keener on being challenged by athletic women than he was by rugged men, but in their case, it was a different kind of challenge – it was a taunt, a tease, it virtually invited him to meet it, and Nathan would never turn down any invitation with such a honeyed promise at the end.

‘See you’re on your own today,’ he said, idling past.

She threw him a quick, incurious glance. ‘Very …’ She was breathing hard, almost too hard to speak. ‘Very … observant of you.’

He nodded and smiled, and then realised that he’d already been dismissed. Mildly vexed, he turned away.

‘Sorry,’ she added. ‘Don’t … don’t mean to be rude. It’s just that –’ she forced a breathless laugh ‘– I’m totally … wiped out.’

He turned back. ‘I’m not surprised.’ The digital reading on the cross-trainer’s VDU was ample evidence of just how hard she’d been at it. ‘Four hundred calories! And this isn’t the only machine you’ve been on tonight, is it? You’re really putting yourself through it.’

She focused on the VDU herself. ‘I like to keep … fit.’

‘Well, you’re …’ He paused. He’d been about to say that she was in great shape as a result, but that could have been construed as overstepping the mark. ‘You’re … certainly doing that.’ He edged away, not wanting to press his opening too much. ‘If you need anything, you know where I am.’

‘Oh!’ she suddenly said sharply. And then, more loudly, ‘Oh! … oh! … OH!’

She came stumbling down off the machine on her right leg, all but carrying the left.

Nathan jerked towards her with a look of concern.

Her face etched itself with panicky pain as she hopped around in a half-circle. ‘Think it’s my hamstring … think it’s just gone.’