Probably not. There might be something particular in the Jomsviking literature that this refers to, and I'd especially recommend digging into the Saga of the Jomsvikings (pdf). The English translation is only 23 pages; you might be able to read it in a single sitting.

Overall, though, I think it's wrong to imagine Vikings as some sort of unbeatable warrior elite. They were just as likely to lose as to win a battle, and despite our TV-addled enthusiasm for Valhalla, historical vikings were ready and willing to back off from a fight when the odds ran against them. This is because only the core leadership and the personal retinues of a few aristocratic elites could be considered seasoned veterans.

Early raiding parties would probably have been dominated by men who were farmers or merchants part-timing as vikings. During the later Viking Age, these seasonal raiders gave way to standing armies that looked completely different. The viking crew executed at Ridgeway Hill in southern England shows that most of the men present were teenagers or just a bit older, recruited or perhaps conscripted into the crew from diverse backgrounds across northern Europe, and only the oldest members had lived a viking lifestyle for longer than three years, judging by their diets.

It would be difficult to get part-time vikings or young viking conscripts to train by fighting to the death, and the armies' ability to back off from a fight when it mattered suggests that the viking leadership typically lacked the power to coerce their subordinates into situations of imminent death. Among the elite retinues who dined at their jarl's table and in lived in his hall, we would expect a more rigorous training regimen and a greater degree of discipline. But these were men whose relationships were cultivated through family and through fostering, as well as long years of gift exchange. And if viking war parties occasionally backed off from a fight, it shows not only the reluctance of the rank and file to cast their lives away, but also the reticence of leaders who would not willingly risk losing followers whose loyalty had taken years to secure.

But the Jomsvikings were something special, and Norse audiences were as enthusiastic for Jomsvikings as earlier American generations have been for the exploits of John Wayne or Clint Eastwood. Their stories should be taken with a grain of salt, while admitting that over the 300 years of the Viking Age across all the diverse societies of the Norse diaspora, some extreme things most certainly must have happened, and some men probably died either by purpose or by accident during training. But if so, it certainly wasn't some sort of regular training program that turned men into vikings—it was an exceptional circumstance that attracted little if any attention.