Nadezya Ostapchuk’s coach worried about performance of this shot putter

The Belarusian shot putter Nadezya Ostapchuk won the gold medal at the 2012 London Olympics. But she tested positive for a steroid. As a result, she lost the medal which was given to Valeria Adams of New Zealand.
Two tests manifested that a steroid’s metabolites presented in her urine samples.
If a sportsperson is caught administering any forbidden medicines, he/she is usually sentenced to a ban of two years. As for Nadezya Ostapchuk, she received one-year ban. Why was the sentence lighter? There were several circumstances which proved the following condition: the shop putter didn’t take any prohibited medicine intentionally.
At the beginning the shot putter blamed his former coach. She confirmed that he had sabotaged her sample.
The Belarusian National Anti-Doping Agency examined this case. The International Association of Athletic Federation also took part in the investigation. It was found out that Yefimov was guilty. This person put powder of methenolone into food of the Belarusian shot putter during the last week before the 2012 Summer Olympics. The coach confirmed that he had worried about the shot putter. He thought that this steroid would help to win.
In fact, it is difficult to understand why Yefimov has done it. He only caused the problem.
Anti-doping agencies accepted these affirmations. That’s why Nadezya Ostapchuk received just one-year ban.
As for supporters of Valeria Adams, they didn’t believe that Nadezya Ostapchuk had not applied the steroid knowingly. They claimed that Yefimov just tried to protect Nadezya Ostapchuk. They affirmed that Nadezya Ostapchuk had taken steroids under recommendations of her coach.
If Nadezya Ostapchuk’s performance was amazing certain months before the 2012 Summer Olympics, her trainer had to be sure that she would win. Why did he worry about her performance?