In the 1st video you can watch sparring training Sergey Tokarev vs. Sergey Bogoslovov. And in the 2nd video you can watch Sergey Bogoslovov doing static holds with up to 100 kg on a pulley system.
Спаринг тренировка с Сергеем Токаревым 13.08.2017 [Google Translate: Sparring training with Sergey Tokarev 13 August 2017]
Статика через блок 11.08.2017 [Bing Translator: Static through block 11 August 2017]
Source: Sergey Bogoslovov