it was mentioned in the 2nd fanbook that tsurumaikada didn't quite like this part and that's why they decided to change this scene in the anime. so the change was planned and agreed on
@minase_nayuki@AnimeGuru100 he actually started building his body while he was still active because when he first started skating with hitomi he dropped her during a lift which resulted in her minor injury
he didn't want to put her in danger anymore and started training (this is from the first fanbook)