The Reds' captain was denied an appearance from February 11 onwards with a foot problem keeping him out after a 2-0 Premier League victory over Tottenham Hotspur at Anfield.
He was back with a number of his team-mates as Jürgen Klopp's charges started pre-season training with a series of fitness drills at Melwood on Wednesday and Thursday.
"I've probably been waiting longer than everybody else," explained Henderson on his return to training.
He insisted that his teammates "have been enjoying the break" but declared that he himself has been "dying to get back into it" after his injury-ravaged end to the campaign.
The skipper continued: "That was disappointing but I'm very positive and dying to get back into the swing of things. I'm looking forward to the hard work. I'm just glad to be back on the pitch."
The England international hoped that he can "stay fit" as he revealed that there have been "a few" Liverpool players that have "had to work hard during the summer to try to get back as quickly as possible."
Liverpool captain "glad to be back"
Joined by 22 Liverpool players including Daniel Sturridge, James Milner and Roberto Firmino - as well as new signing Dominic Solanke - Henderson explained that "it has bene all go during the summer" and that he was "glad to be back."
Sadio Mané and Danny Ings, also returning from long-term injuries, trained away from the group. As did Mamadou Sakho, back from a loan spell with Crystal Palace in the second-half of the season, with Lazar Marković returning from a six-month spell with Hull City.
Another player back from a loan period last term was full-back Jon Flanagan, who joined the group having endured an unsuccessful temporary spell with Burnley last season.
Henderson added that it was "nice to see Flanno back" to the club's official website and noted that the Englishman, who is unlikely to have any future at Anfield, "did well in the running" and "has been doing a little bit of work over the summer."
"It's good to see a lot of the lads come back from their loan spells or from injury," the 27-year-old said. "I’m very excited about what we can achieve as a group."
Henderson was undoubtedly missed last season, although his injury allowed Emre Can to return to the fore, and having established himself as a deep-lying playmaker in the No.6 role, he will play a key role this coming season with Liverpool two games away from a return to the Champions League proper.