Jurgen Klopp made "a classic mistake" by implementing his demanding style at Liverpool too early, according to former Wales coach Raymond Verheijen.
Klopp succeeded Brendan Rodgers in October, but has endured mixed fortunes at Anfield so far, with inconsistent displays underlining a stuttering Premier League campaign, while they also suffered disappointment last month in losing the League Cup final to Manchester City.
Injuries to key personnel have not helped Liverpool's cause, with Klopp admitting in December that "hamstring is the s*** word of the year" after he lost Daniel Sturridge, Philippe Coutinho, Kolo Toure, Christian Benteke, Divock Origi and James Milner to similar muscle problems.
But Verheijen, who has worked as a fitness coach with Bayern Munich, Barcelona and Netherlands in the past, says the 48-year-old should have heeded the warning signs during a difficult final season with Borussia Dortmund before introducing his high-intensity pressing game from the outset in England.
"Jurgen Klopp has hopefully learned a valuable lesson at Liverpool," he told Omnisport. "They implemented the style they were successful with in the first few years at Dortmund. In the last few years they had a lot of injuries and little success, so you have to put their achievement into perspective. But he's a top coach, you can't deny that.
"But they made the classic mistake, like Louis van Gaal [at Manchester United] – they implemented their approach irrespective of the circumstances.
"Liverpool used to play a passing game with Brendan Rodgers. When you have possession, you spend less energy. So the playing style was less demanding and the players adapted to that.
"When you implement a more demanding pressing game, the bodies of the players need time to adapt. But if Jurgen Klopp had analysed the situation when he started, he'd have realised they were about to play the most games of anyone in Europe. He implemented a more demanding pressing game in a period when players had less time to recover.
"What you ask from the players is to recover from more fatigue in a shorter space of time. You don't have to be Einstein to work out that that's impossible."
Verheijen also expects Tottenham to suffer during the closing weeks of the season as a result of a similarly taxing approach encouraged by boss Mauricio Pochettino.
"Spurs are in a flow, they're great to watch, but what you often see is that his teams run out of gas in the last part of the season," he said. "That happened at Southampton and in his first season with Spurs.
"They had some setbacks in the last few weeks, so now the question is will they be able to pick up or will this pattern of losing and drawing develop further. It's a critical moment for them.
"He really wants to improve his players individually and his teams as a whole. In pre-season they had double or sometimes triple sessions.
"But that only works with young players. If Pochettino applies this approach with all the players, it will be a big problem because they will not be able to maintain it.
"The smart thing he does is that he rotates his team in relation to the Europa League. Although rotation has a negative effect on the tactical development of your team, to keep your players fit and fresh for the whole season, it's the only thing you can do."
Liverpool host Manchester United in the Europa League on Thursday, while Tottenham travel to face Dortmund.
