Arne Slot's side suffered their 18th defeat in all competitions this season, leaving champions Liverpool fourth in the table on 58 points with three matches remaining despite spending around 446 million pounds ($603.84 million) to improve the squad.
Van Dijk was asked about online claims that Liverpool's training schedule has been light, including suggestions players were on holiday last week.
"I'm not sure it's a holiday. It's a city trip," Van Dijk told reporters. "If you have one day off - and you don't have many days off - people decide what they want to do with their families. We are not kids. Everyone is an adult.
"I wish we had a couple more days off at times because I think it works both ways. You see Pep Guardiola giving Manchester City three days off in the last weeks in a row and they are doing pretty well. It is about finding the right balance.
"I can understand if people think we are not training, and when results are not there it could be seen as a reason why we are not getting results."
Liverpool will finish the season without silverware after exiting the FA Cup and suffering a heavy defeat by Paris Saint-Germain in the Champions League quarter-finals.
They host ninth-placed Chelsea.
"I want this to be solved," Van Dijk added. "I want us to experience what I have had over my time here. I want us to be successful... We have to realise that next season, this season cannot be repeated. It is unacceptable."