Olympic rowing champion Katherine Grainger has insisted that she has the necessary "desire and drive" following her return to the sport.

The 39-year-old took a break after her exploits at London 2012, but in September, she announced that she had restarted training.

Having finished second in the single scull at the 5km GB Rowing Team Assessment in Boston this weekend, Grainger admitted that it had been "a decent start".

"I think it's nearly three years from my last set of trials at Boston so I was prepared for these to be a bit of a shock, but I was happy on many levels," she told reporters.

"As for my own performance I still have a long way to go yet to where I want to be but it was a decent start after a few weeks back training and has reassured me that I still have the desire and drive for competition that I've always had."

As well as winning gold in London, Glasgow-born Grainger has three Olympic silver medals to her name.