"Training on your own for an individual sport is important as it builds resilience and mental toughness," said Eitelberg, a triathlon and open water swim coach and strength and mobility trainer.
"But the stimulation gained from a group environment can never be underestimated. Learning from those around you as well as the natural competitiveness of a group allows you to achieve more from training. It also provides the motivation to train during the colder and wetter months."
The Fitness Locker group are not lacking in motivation. They have a membership base of over 60 athletes from all over the North Island, as well as a handful from the South Island and abroad.
"One of the biggest appeals to prospective members is the club culture we have created, bringing a social aspect to training and events around the country," said Eitelberg.
He is a good man to be in the centre of it all, having competed in triathlons for more than 20 years.
Eitelberg has also represented South Africa and New Zealand at age group level.
The general focus of the group is on upcoming triathlon events, with groups building towards the ironman distance, half ironman distance or sprint/standard distance events.
The majority of the athletes are building their base for next summer but many are also looking to peak over the next month for the World Triathlon Champs in Edmonton, the Xterra World Champs, Sydney Marathon, an Iron Distance Event in Indonesia and a couple of adventure races in China.
The Fitness Locker coaches aren't afraid to back up their training on the trails. At the Tauhara Trail Run, two of their coaches led from the front in the half marathon with Erin Furness (Hamilton) winning the women's race and Olly Shaw (Rotorua) claiming second in the men's. The times for their athletes varied from 1 hour 31 minutes to 2 hours 48 minutes.
At the Taupo Half Marathon the Fitness Locker team had a big turnout of athletes and they delivered again. Furness finished second in the women's and another two athletes earned top three category placings. They had three debutants at the distance and a further three personal best times set.
Eitelberg was pleased with the time variance of 1 hour 26 minutes to 2 hours 15 minutes for a big group.
"To top it off, one of our athletes' 11-year-old son won the youth category in 1 hour 50 minutes and we're hoping to coach this talent in a few year's time."
As you'd expect there is a healthy dose of competitive spirit in the Fitness Locker group.
"I've heard many athletes say they simply want to complete a triathlon for the fun of it, but as soon as they've completed that event, they're already looking at ways to beat the next person in front of them! ... We have both professional and experienced athletes who are always happy to mix it up with the less experienced. We look after each other."
One of the original concepts for Fitness Locker was that there could be just one Aucklander travelling to an event in another part of the country, but add in one from Hamilton, another from Napier and that athlete is not alone.
Eitelberg said in the past two summers they have been the only triathlon club officially present at every major triathlon event including national champs events and the national series.
He said for anyone who is looking to stay fit over the winter, the key is consistency in their training.
"The weather can be unsafe at times to train in, there's other commitments and sometimes we just can't be bothered. Doing something is better than nothing and even if the desired training miles or times are not achieved, a regular routine will still achieve plenty and take the pressure off once summer approaches."
He offered similar advice to the people training at Fitness Locker, continually reminding them of perseverance and patience.
"It takes time to implement new concepts and see the results, but once that switch is flicked, there's no turning back. There's another simple yet still hugely underestimated concept that athletes need reminding of, the value of recovery."
Taupo 63.3 Series
Final event - Kinloch Offroad Marathon
When: Today
Where: Kinloch, Taupo
For more information visit: www.633.co.nz
For more information on Fitness Locker visit: http://www.fitnesslocker.kiwi/