In modern times, interval training is a fundamental way to train endurance performance. I overheard my 10-year-old telling his brother, “the best way to get faster is to do intervals, that’s what my gym teacher said.” For the general public, any intervals will do, but for the highly trained endurance athlete we need to get a little more scientific. The basic premise of interval training is that you are able to swim, bike, or run at a higher intensity if your training is intermittent versus continuous. A 5k runner, for example, could head out the door and cover 3.1 miles as fast as possible a couple times a week, but would have a hard time holding their goal pace for much more than one mile. Instead, if the training was broken into half mile intervals, a race-pace could be achieved with every 800 meter bout as long as recovery was adequate. With each repeated bout there is a cumulative effect, up to a certain point, to stimulate adaptation. Beyond a certain point, maladaptation can occur. Types of Intervals In an effort to simplify we will focus our discussion on the most potent type of intervals known as VO2 max intervals. VO2 max is defined as an individual’s highest rate of oxygen consumption (milliliters of oxygen per kilogram of body weight per minute). A common misconception is that interval training is strictly anaerobic. These types of intervals do have a big anaerobic component, but by definition have you operating near your peak oxygen consumption, which is the key. Most athletes can work at VO2 max for only about 5 to 9 minutes, so intervals at VO2 max need to be shorter than that. If the interval is too short, then the anaerobic contribution is big, but there is not enough time to actually get to VO2 max. Personally I like 2-3 minutes ON with about equal recovery. Pacing Strategy Pacing is critical. Suppose you are running those 800 meter bouts and you start out by sprinting the first 200 meters and then have a gradual slow-down for the next 600 meters. Your average pace might be on target, but you have failed to reach VO2 max since you started with this huge anaerobic effort and then settled into a pace slower than your VO2 max intensity. There is something called a slow-component to VO2 max. This means that for any pace above lactate threshold, you will eventually reach VO2 max if the exercise is continued. So you do want to go fast, but to spend the most amount of time near VO2 max, you want a pace you can sustain for 2-3 minutes. If performed correctly your oxygen consumption will approach VO2 max about half-way through each hard effort. So if your workout is 6 x 2.5 minutes, you might in reality only spend a total of 7.5 minutes at VO2 max, which is fine. If performed poorly you may only spend a few seconds of each interval at VO2 max or none at all. Graph 1: Poor pacing strategy with high power output (purple) at the start of each bout and power dropping on each bout. Graph 2: Better pacing strategy here. In this case, power (purple) within each bout was very consistent, but there was still a drop off in power for the last 3 bouts. Graph 3: Power (white) fairly consistent throughout hard efforts. Notice peak heart rate (orange) is not achieved until the 6th bout. Different athletes, different software. Work:Rest Ratios An ideal range for work portion is about 1.5 to 4 minutes. We like the 2-3 minute range the best with a few exceptions. Work to rest ratios are usually around 1:1. The rest interval can be adjusted to increase or decrease the intensity of the workout. If you are having a hard time keeping pace, try adding 30 seconds rest. If you are completing the workout with energy to spare, try 30 seconds less rest the next time out. How Intense? Pace or power are your best guides for this type of training. Heart rate lags so far behind that it is not the best indicator and you don’t want to try to spike your heart rate to start each effort. If you have power on the bike, I like to use 110% FTP for 3 minute bouts, and 115% FTP for 2 minute bouts. For running, a 5k race pace or slightly faster will get you there. A 15 minute 5k runner can just use their 5k pace, but a 25 minute 5k runner might need to increase the pace slightly. If you are performing intervals uphill and don’t have power or pace to guide you, try this approach. Warm up to the base of consistent climb. On your first bout, hold back a fraction and note your distance at 1 minute and 2 minutes. Make a mark in the dirt. Recover on the downhill and repeat the same section of the hill attempting to at least reach the same finishing mark or go slightly further. Try to do this without going any further for that first minute. How Much? I mentioned earlier that this is the most potent form of training. So your goal is to be able to maintain the quality for the entire workout. For most people this means 15-21 minutes of total hard work. So that is 8-10 bouts of 2 minutes, or 5-7 bouts of 3 minutes. Keep it simple. Shoot for a very similar intensity every time and if you start to slow down you have done too much. How Often? A little bit can go a long way. I try to space out this type of training more than any other. For most people that means two quality sessions per week with one on the bike and one on the run. Training becomes more polarized during a VO2 max cycle with recovery and endurance workouts separating VO2 max bouts. Total training volume is reduced and avoid excessively long workouts during this time. Soon Ripe, Soon Rotten With this type of training, most people will plateau in about 6 weeks. I like to sprinkle in this type of training as key races are approaching and save heavy blocks of VO2 max interval training for the most important races of the season. Josiah Middaugh is the reigning XTERRA Pan America Champion and 2015 XTERRA World Champion. He has a master’s degree in kinesiology and has been a certified personal trainer for 15 years (NSCA-CSCS). Get to know Josiah Learn how to use Suunto Spartan's Interval feature

Most people call me Mel. I’m from Queensland, Australia, and I do triathlon. I used to be a professional runner with my main events as the 1500m and 3k steeplechase. I swapped to Tri in 2010 – I couldn’t afford to be a runner, and I kept getting injured. I gave triathlon a go, made some money, and kept doing it! Mel's background is in running – but now she loves the bike. © Thierry Sourbier, onlinetri.com I just jumped in. I did a small local race one weekend before to put it all together, and then just jumped in a half Ironman. The half is my favorite distance. You can do 70.3 every weekend, and I like racing, so I do that. It’s not so tough on the body and you don’t need the recovery time of the longer races. I only started swimming for real in 2010. I never really liked the water, I was more a land person. I could swim, of course, every kid in Australia grows up at the beach – but I used to get my mom to write me notes to get out of swim class! Swim is still my weakest part of the race – I never enjoy a swim. My favorite swim is Sunday afternoon for an ocean swim. I don’t hate it like I did when I first started. If I retired tomorrow I’d probably never get in the lap lane again. I’ve tried everything in the water and don’t improve – I’d swim the same times if I swim 30k a week or if I sat in the chaise lounge next to the pool. It totally does my head in! I love the bike. I usually try and ride hard, and get to the front in the bike leg, and make up what I’ve lost in the swim. To be honest, it’s my favorite part of the race. Mel on her way to a win in Ironman Western Australia in December. © witsup.com But the run is my strongest leg. I put more effort in the bike, but I can leave it all out there in the run – I think I have a better pace judgement in running, and know not to go out too fast. I’ve got a lot more KMs in my base as a runner than most triathletes. My training is a little unorthodox. I guess coming from a running background, I train quite differently – when I first started I went with a tri coach but I just didn’t agree with how he was doing things. Now my husband coaches me. I actually do a lot less running than most triathletes. I was getting a lot of injuries, so I bought a bike and got quite good at that. I do most of my base work there. I run up to 70k a week, where as most athletes do up to 100. But I do a lot more on the bike than them. I’ve got a few injuries. Most of my injuries have been in my running career – every stress fracture under the sun. I ruptured my hamstring tendon, after it had been tearing, but it wasn’t diagnosed, and it was six months till I got it fixed. So now I have two muscles going through one tendon. I have a broken rib that just won’t heal. That’s life! I love the hometown crowd. I used to always say Phuket was my favorite place to race – I just love the location. But the race has changed a bit, and now I really love racing in Australia – but I don’t get to race their often. Stay tuned for Mel's triathlon training tips! Main image © witsup.com

Watch the video and experience the first ever Suunto Summit that was held in October, 2016. We are thrilled to share the selections for the Suunto Summit 2017. After hosting an open, public application process, we received inspiring motivation letters and stories from all around the world. Within our final group we have authors, awarding- winning photographers, influential bloggers; we have XTERRA world-champions, and winners of major ultra-trail races. Balancing these inspiring experiences and accomplishments was a challenge, but we are thrilled to have had so many inspiring applications that shared a synonymous passion for being a part of the Suunto community. Stats: 6 female, 9 male 9 from Europe (2 France, 1 Spain, 1 Finland, 2 Sweden, 1 Norway, 1 Latvia, 1 UK, 1 Switzerland) 2 from USA, 1 from New Zealand, 1 China, 1 Malaysia. Suunto Summit 2017 participants: Arnau - Spain Diane-Perle - Switzerland Marta - Latvia Marit - Norway Mia - USA Barbara - USA Petra - New Zealand Ramon - Malaysia Sebastien - China Pelle - Sweden Jean-François - France Tim - United Kingdom (UK) Mathias - France Sante - Finland Oskar - Sweden Congratulations to all selected, and a huge thank you to all who applied and shared their passion with us! - Suunto Team

The World Vertical Week is about collecting vertical meters for your country and your sport. All moves in all human-powered outdoor sports count. To keep the playing field level, we were only comparing averages. A cumulative number of ascent meters per country would not have made sense as the population and number of Suunto App users varies.  Skiers are still quite clearly the queens and kings of the hill with 849 meters of ascent in average. The mountaineers climbed on the second spot with 636 meters and the trail runners rounded out the top three with their 400 ascent meters. Actually the order of the activities remained almost identical compared to 2016: the only difference was that mountain bikers passed the snowshoers in the listings. Average ascents in various activities Ski touring 849m Mountaineering 636m Trail running 400m Mountain biking 362m Snow shoeing 316m Trekking 293m Cycling 236m Cross country skiing 222m Running 104m   SKI TOURING IS NUMBER ONE – BUT WHO SKIS THE MOST? Now that we know that ski touring is the sport with the biggest average ascents, it is time to dig deeper. The snowy winter in the Pyrenees has boosted the skiing spirits of the Spanish and they were the only athletes to cross the thousand vertical meter mark – in any country and any activity. Felicitaciones, españoles! Top 10 countries in ski touring Spain 1034m Switzerland 938m Slovakia 936m Germany 927m Andorra 916m Italy 909m USA 883m Austria 877m Poland 874m France 858m   A SLIGHT SURPRISE IN MOUNTAINEERING Mountaineering was second in the activity listings. But the leading nation within that activity was a slight surprise: United Kingdom surely has a long mountaineering tradition, but only a few – at least here in the Suunto office – would have bet their money for the island nation. The UK was not among the top mountaineering nations last year, but still they took the first place with 836 meters in 2017. Top 10 countries in mountaineering United Kingdom 836m Italy 772m Switzerland 749m Germany 713m Japan 685m France 683m Austria 655m Taiwan 620m USA 600m South Korea 575m   ASIAN COUNTRIES DOMINATED TRAIL RUNNING It was clear already last year that China, Hong Kong and Japan are strong in the trail running segment. This year they occupied the top three with excellent performances and clear margins. Maybe having the Vertical Week in winter limits the possibilities for trail running in mountainous areas in Europe and North-America but still the Asian performance was impressive. Great climbing, China, Hong Kong and Japan! Top 10 countries in trail running China 887m Hong Kong 808m Japan 711m Italy 572m Portugal 540m Spain 524m United Kingdom 509m Slovenia 469m Greece 468m Austria 437m   CLOSE MARGINS IN COUNTRY COMPARISONS We also analysed the data for all human powered outdoor sports and compared the average ascents between countries. The margins were tight, but still there was one above the rest: The Austrians ascended on average more than any other nation, 320 meters per every workout tracked during the Vertical Week. Top 10 countries overall Austria 320m Italy 298m Switzerland 287m Spain 261m Slovenia 261m Portugal 258m Hong Kong 247m France 240m Norway 235m Slovakia 218m   TOP COUNTRIES IN OTHER ACTIVITIES And to give you even more to speculate here are the top countries in the other activities mentioned above.   Top 10 countries in mountain biking Italy 515m Slovenia 479m Spain 471m United Kingdom 465m Austria 461m Switzerland 443m South Africa 416m France 370m Germany 367m Poland 366m   Top 10 countries in snow shoeing Italy 564m Andorra 530m Austria 510m Germany 429m France 424m Switzerland 345m USA 228m Spain 213m Canada 178m Finland 163m   Top 10 countries in trekking France 406m Italy 397m Austria 353m Poland 322m Spain 307m USA 274m Germany 271m Norway 243m United Kingdom 229m China 141m   Top 10 countries in cycling Spain 405m Italy 403m South Africa 393m Colombia 392m Portugal 355m Cyprus 332m Switzerland 328m Czech Republic 308m France 298m Austria 294m   Top 10 countries in cross country skiing Czech Republic 391m France 312m Poland 286m Norway 270m Sweden 266m Italy 260m Austria 252m Canada 225m USA 222m Germany 221m   Top 10 countries in running Portugal 157m Hong Kong 151m Slovenia 148m Switzerland 136m France 128m Spain 127m Norway 126m New Zealand 124m USA 117m Czech Republic 115m   Main image © Patitucci Photo

World Vertical Week was held last week and the hundreds of pictures tagged with #verticalweek on Instagram give a great overall look into what people have been up to during the week. Three of the most inspirational photos were taken by Hollie Holden, Sami Renner and Christoph Oberschneider. Each one of the winners will receive a new Suunto Spartan Ultra to accompany them on their future adventures. 🌲// Legs/entire body felt like an 🐘 at this weeks @vanrunco trail ✈️ crew BUT I managed to hit my @suunto #VerticalWeek goal of 4000m (1k more than my 1st goal! 🙌) of climbing and we were blessed with a pretty layer of 'convenient snow', right @coralie2700 ? 😉🤣❄️ A post shared by Hollie Holden (@holholden) on Mar 5, 2017 at 12:59pm PST “The Vertical Week was a great opportunity for me to start building my strength and climbing skills ahead of my upcoming training season for my 1st 50 mile Ultra Marathon - the Squamish 50 in August which is a tough, mountainous course with 11,000 feet (3350m) of climbing! I set myself the goal of covering a similar amount of climbing during Vertical Week so I spent a lot of time on a local trail called the BCMC which starts at the base of Grouse Mountain climbing to the top. This trail has 850m of elevation gain in just 3km of climbing! I ended up doing this trail 4 times in the week (3 times within one 24hr period!) then finished off the week running trails with my local run crew, Vancouver Running Company Flight Crew, surpassing my 3k goal and hit 4000m for the week instead! The weather in Vancouver has been unseasonably cold, with lots of snow & wet rain and I wouldn't have done anywhere near as much climbing last week if it wasn't for the awesome community of friends that I have here who are willing to come climb mountains in a snow storm with me!” –Hollie Holden, BC, Canada Cause she asked so friendly... 🐦 #lovemountains #skimo #verticalweek #collectingmoments #mountaineering #watzmann A post shared by Sami (@samirenner) on Mar 5, 2017 at 10:10am PST “The photo was taken on the last of three summits at the “Watzmann-überschreitung”, a famous summer tour in my hometown with over 24km and 2500m of climbing. The goal for me was to do this very technical tour with skis. As I reached the third summit, I shared my last Powerbar with a bird. A few days earlier during the Vertical Week I was in Zermatt, reaching Breithorn’s (4164m) west and east summits on skis, and on two more skitours. All in all, my Vertical Week was about 7500m of elevation gain over 65km.” –Sami Renner, Germany Welcome back, #winter! Yesterday was a great #powderday in @visitgastein. Can't wait for more! A post shared by Christoph Oberschneider (@coberschneider) on Mar 2, 2017 at 3:09am PST “I work as a backcountry skiing photographer in Austria, so my goal each winter season is to capture the beauty of backcountry skiing & ski touring, to share my passion for the sport with as many people as possible and ultimately to get more people to enjoy life in the outdoors. So far we have had a very dry winter here in the Alps, so getting good shots has not been an easy task. So when it finally started snowing 10 days ago, I headed out to Sportgastein (a freeride spot close to Salzburg) with two good friends. We found some beautiful lines in the backcountry with lift-supported ski touring and I managed to get some good shots. And that's how I also spent the rest of the Vertical Week, ski touring in the mountains around Salzburg and trying to capture the beauty of the winter landscape and some more skiing action before the snow starts melting again.” –Christophe Oberschneider, Austria Congratulations to our three winners and thank you very much everyone for sharing your Vertical Week moments!

Debi Hazelden has broken the record of most half-ironmans in a row. Debi’s on top of her game With 40 runs, bikes and swims under her belt, Debi is going strong – and going quick, averaging just under 5.5 hours. While according to the daily update blog, she’s feeling the physical drain, she’s also full of energy and raring to go. And the pictures? Debi looks as fresh as a high-school track star pacing the 10-minute-per-mile group at the local Turkey Trot. Of course, Debi’s been sneaking a carrot cake every now and then – she deserves it! …but it hasn’t been easy. The biggest challenges up to this point? “Illnesses – Our 7 month old son goes to daycare and has had his first couple of viruses which have been passed onto me! I had Hand Foot and Mouth in the first week and in the 4th week I’ve had a cold. Bad news for John Unfortunately for John, an injury had him sidelined on the advice of a doctor. Says John: "As most of you know, I have encountered a glitch on route to my immediate goal. I have an inflamed VMO muscle for which I am currently receiving treatment. The injury has prevented me from running.” It was the first the right one, then the left one – John’s done some physio and is back to logging KMs, but at well below intended volume, and he’s too far behind to catch up. What can he still do? Help Debi – which he’s doing plenty of, whether it’s beside her on the bike, in the pool, or on the track. The weather’s been all over the place From a high of 43-degrees celsius to wild thunderstorms with 70kmh winds, and one day with nearly ten centimeters of rain, the weather has been a challenge – especially when there’s no putting off your bike or run till the next day. Hey, at least in the pool you’re already wet. She’s had plenty of help A challenge like this is impossible without support – in addition to her core team, local members of the run/bike/swim community have been coming out to keep her company. If you’re in the area, head on down to Centennial Park and look for the white RV! The swim is easy "It’s definitely a surprise we look forward to the swim each day,” says Debi. “It’s not usually our favourite discipline. it’s like a recovery session for the body with no effort.” Ryder – and several others – joined Debi for the record-breaking day. Don’t worry, Ryder has baby sitters – and a stroller One of the most remarkable things? John and Debi are doing this less than a year after having their first baby. Ryder is logging plenty of distance on his personal Suunto as he gets pushed around on his stroller during the ‘run’ portion of the race. Only 60 more to go With the world record already in the bag, some of the pressure is off – but the work’s not done yet. The goal is 100, and Debi’s less than half-way done. There’s sure to be more drama – follow along on their Facebook page and stay tuned here for more in-depth updates!