It's all part of a new workout regiment that has Ristolainen feeling faster and more powerful than ever before. And it began with a phone call, shortly after the Sabres' season ended in April.

Ristolainen's offseason routine was a topic of conversation among fans and media on social networks throughout the summer. A quick glance of his Instagram finds the Sabres defenseman flipping tires, boxing, clean lifting and practicing mixed martial arts.

"We've been following you on Instagram," the woman said. "Looking good."

Following an informal skate in August, Rasmus Ristolainen was joined by a man and a woman - presumably Sabres fans - upon boarding the elevator at Harborcenter.

Ristolainen spoke candidly to the media on locker cleanout day, less than 48 hours removed from the conclusion of a fifth-straight losing season. He said the Sabres needed to change, to a man, and called on himself to be a better, more vocal leader.

"I was really, really pissed and disappointed," Ristolainen said. "It took a while to kind of forget everything, you know? It was good to have a long summer, kind of take your mind off [the season], don't even look at your hockey gear and try not to think about hockey."

Not thinking about hockey should not be confused for a lack of preparation. For years, when asked about playing some of the highest minutes in the NHL (his average ice time of 26:04 since 2015-16 ranks fourth in the league), Ristolainen has offered the same response: That's why you train in the summer.

This summer, he wasted little time. His trainer, Ville Rintala, said it had only been days since the season ended when Ristolainen reached out, the motivation apparent in his voice.

"He called me the minute he landed to Helsinki, Finland, at the airport," Rintala said. "He called me and asked me, 'When are we going to start?' The minute he landed."

Ristolainen got to know Rintala last summer, when the two were introduced through a mutual friend and began to train together once per week. Rintala's background is in combat sports, but he estimates he trained some 200 junior-level hockey players last year.

Rintala said he identified weaknesses in Ristolainen, which caught the defenseman by surprise. As the summer wore on, their workouts together became more frequent, evolving to two and then three times per week. They developed a friendship, and Ristolainen decided to train with Rintala full-time.

When the two linked up this summer, they shifted their focus. Rather than placing an emphasis on strength and barbell lifting as Ristolainen had done in the past, Rintala convinced the defenseman to concentrate on building speed and explosiveness.

"Before this summer, around eight summers, I did more Olympic lifting and tried to get more power, max power in the gym," Ristolainen said. "This summer, we totally changed everything. The main goal was to be better on the ice. We stopped lifting heavy, did dumbbell stuff, mobility, sprints. That kind of stuff."

Barbells were replaced with dumbbells, kettlebells, weight vests and 20- to 50-kilogram slam balls, which are weighted medicine balls. They managed their workout intensity to maximize volume, with the goal of training five days per week while still leaving room to recover after each workout.

"His minutes, they are high, and that's why our offseason is pretty high-level," Rintala said. "We have to push the body to the limits. When we had rest, we didn't have a complete rest week, we had a recovery week. We still trained, but the intensity was a lot lower and we did a lot of recovery training."

The results? Ristolainen said he took the ice feeling lighter, faster, and more powerful. Rintala took that description a step further.

"If you want my honest answer, he's leaner, he's meaner, he's more explosive, he's faster. His endurance is insane at the moment," he said. "… I'm waiting for Rasmus to get on the ice and see how his conditioning is going to last. I know he's going to be even better than last year, conditioning-wise."

…

On his best days, Ristolainen plays with a mean streak that boils over to the several responsibilities he shoulders in a game. He's not only been tasked with playing big minutes against top lines, but also quarterbacking the power play and often being the first man out on the penalty kill.

Marco Scandella played alongside Ristolainen more than any other defenseman last season, his first as a Sabre. He came to notice how Ristolainen used his physicality as a means of becoming engaged in games.

"He likes to get physical, get involved in the game with a big hit or a big play early," Scandella said. "The guy competes every night. It's fun playing with him."

Ristolainen brought that same level of intensity this summer, working under Rintala with 10 other athletes from various sports. The group included a professional floorball player, a member of Finland's national women's hockey team and multiple mixed martial artists, including UFC fighter Teemu Packalen.

Rintala says each athlete had their areas of strength, Ristolainen being the best of the group when it came to power training. Evidently, that wasn't enough.

"The floorball player, he was better in coordination training," Rintala said. "So that's something that, when Rasmus saw that the floorball player was better than him in the agility training, he wanted to be better than the floorball player. That's how he improved. He wanted to be the best."

Ristolainen holds Packalen and others in his line of work in high regard - "I have a huge respect for those guys. I wouldn't have it [in me] to be a UFC fighter," he says - but Rintala sees similarities in the two.

"He is a crazy beast in training," Rintala said. "He does everything. All summer, he prepared every day for the next training session.

"I think we counted, we had complete training sessions of 85 days and around two-hour training sessions each day, from Monday to Friday, and we didn't skip one training session this summer."

Scandella offers a similar description.

"He's a big moose and pushes weights around like they're featherweights," Scandella said. "He's just a beast out there. He works hard, takes care of his body, is focused. He brings that professionalism to the rink every day."

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In the early months of last season, Ristolainen found himself lying in bed while his teammates were battling on the ice. The defenseman was sidelined for most of November with a lower-body injury, a difficult experience for a player who prides himself on his availability.

Ristolainen recounted the experience to Rintala when the two went for lunch at the end of the summer, one day prior to his return to Buffalo.

"He told me that when you get injured and you have to lie on the bed, and everyone is playing, especially at home games, he realized how much he loved the game and how much he wants to be on the ice," Rintala said. "The same thing happened during the summer."

That enthusiasm has been apparent during the Sabres' informal skates at Harborcenter, where Ristolainen's voice can be heard issuing warnings to his teammates from the bench. He's making it known: once training camp begins on Thursday and competitive practices are underway, they're going to have their hands full with No. 55.

The Sabres, of course, wouldn't have it any other way. There's going to be another young, talented defenseman named Rasmus on the Sabres roster this season, and he'll need guidance. After skating with Rasmus Dahlin for the first time this summer, Ristolainen said he's up to the task.

"I need to be a better leader, vocally and by example, and so does everyone else," he said. "It just doesn't need to be one or two guys. We need to be a better team, we need to be a tighter team. We've got a young kid here, he looked really good out there. He needs someone to lead on and off the ice."

Training photos courtesy of Tommi Mankki