Kirsten Hellier, now coaching Chinese shot putters, has finally revealed why she split with world champion Valerie Adams - just as news broke that Adams is also quitting the coach that replaced her.

Speaking candidly for the first time about the details of their messy split - and before details became known of Adams' new decision to walk away from new coach Didier Poppe - Hellier says the pain was still "raw" and concedes she has occasional second thoughts about her decision to walk away.

Talking to the Herald on Sunday in Guangzhou, China, where she is coaching Chinese athletes at the Asian Games, the New Zealander admits she'll be happy to see the back of 2010.

"[Since the split] I have had some second thoughts - it would be dishonest to say I haven't. It was a massive decision but it wasn't done overnight."

Hellier says she felt Adams had seemed "unhappy" since late 2009. "I tried to find the answers but I couldn't. It got to the stage where I knew I couldn't give her what she needed. I had always said to Val that if it ever got to that point, I would walk away - or tell her to move on.

"I don't believe she was stagnating [in performance] - she just seemed unhappy and that kind of broke my heart."

Hellier says the delicate situation was exacerbated by difficult contract negotiations with Athletics New Zealand.

"The reality is I wasn't happy, she wasn't happy and a decision had to be made. I made that decision - but if you look at the press conference, [it seems like] the decision was hers. I guess it depends who you talk to."

After the world indoor championships in March, Hellier had made up her mind to go but didn't want to discuss it with Adams until after the national championships. One of Adams' support team became aware of Hellier's decision. "I was given an ultimatum," recalls Hellier. "This person basically said 'if you don't tell her [now], I will'. I wanted to wait until after nationals so she could compete well and it was done properly."

The split did not happen in private. Instead it felt like a "messy divorce", with a meeting in a cold boardroom with lawyers and agents.

"It was taken out of my hands. I believe that if we had sat down and talked, the transition would have been smoother. It was done for the right reason and I think Val would agree. I genuinely want success for her and Didier."

Hellier and Adams keep in semi-regular contact, and talked on Skype last week. "It's general stuff," Hellier says. "We never talk about the sport."

However, Hellier believes her new charge, Li Ling, could challenge Adams at the 2012 Olympics.

"I'm not going to lie - it would feel strange to be there watching Val, absolutely," says Hellier. "But I would want my athlete to beat her; to throw further and do better. I'm a passionate Kiwi through and through but I wouldn't take an athlete that far without giving them all of my knowledge and everything I have."

Hellier was contracted by the Chinese in May and has been working with Ling, their No2-ranked female putter, for the last three months. Ling trained in New Zealand for six weeks recently and Hellier says her progress has been remarkable.

"In training, she has gone from throwing [in the] late 17s [17 metres] to over 19 consistently. Strength-wise, there have been gains of up to 25 per cent in her core lifts, which is phenomenal. Like most Chinese putters, she has great natural speed but needs to work on her strength and technique. The small changes we've made have made a huge difference."

The 25-year-old Ling placed fourth at the 2007 world championships with a throw of 19.38m. Four years on, that remains her personal best. Hellier doesn't know the reason for the stagnation but was unimpressed with Ling's training systems and methods.

"There was no real programme in existence. She showed me her weekly [training and weights] plan and it had never changed - apparently it had been the same for years. It was pretty pathetic - even at Les Mills you would get a better programme and this was an Olympic athlete."

Hellier has no doubt Ling has the ability to manage 20 metres-plus regularly - which would put her into medal contention in London, against a certain Valerie Adams.

When the Asian Games conclude on Friday, Hellier will be meeting with the Chinese officials to discuss her contract extension. Relocating to China has been considered but Hellier is reluctant to transplant her two children (10 and 14 years old) and the international schools they scouted in Beijing cost a whopping US$27,000 ($34,700) per year.

The preferred option is for Ling to base herself in Auckland, which Hellier thinks would be "hugely beneficial" for her as an athlete and a person.

* Michael Burgess is in China with the support of the Asia NZ Foundation.