I turned 45 this year. I completed Ironman World Championships and after a long season of swim/bike/run, I needed a physical and -- more importantly -- a mental break. I find the break comes not from reduced training but more so from not obsessing about the training. In short, doing whatever feels right. I did not do much of a scheduled training load for the first 30 days besides swim and run occasionally with no biking whatsoever.

In the beginning of November I set my sights on a goal to complete a swim for 30 days in a row.

Think of the issues which many of us consider “limiters.” Poor core strength, inefficient running form, curtailed training time and suboptimal balance in the pool are but a few of the many limiting issues heavily discussed on forums such as these. However, consider the limits offered by the biases inherent in the way we make everyday decisions. Recognizing these human foibles might offer the most powerful opportunities for improved performance.

Limiters or “limiting” can be scary words as they reference something we may not be good at. The reality is, if we want to improve, we have to face that fear of what we aren’t good at -- or simply need to improve at -- and find a way to change it. One area I find lacking in most of the athletes new to me or that I continue to work on with developing athletes is what I call “back half race strength.”

Limiters. For the last two years that is all I’ve been thinking about. Alan and I have been working through the elite athlete checklist. First is the body, making sure my legs are big enough and my waist is small enough. Then there is the strength aspect, measured pretty much in pull ups and squats. And then there’s the V02max part, measured in CP5.

This is all well and good, and before you do anything you need to be able to measure these attributes, assess where you currently are, where you need to be and how to get there. There is a lot written about this; but what’s not typically written is what happens to you inside your head while tackling your limiters.

In my last article on early season limiters I suggested three potentially performance-limiting factors which are often ignored by the performance oriented athlete but are absolutely integral to building the type of training that will lead to the highest potential level of performance later in the season. In summary these are:

• Strength
• Aerobic Base
• Mobility

If there is one biomotor ability that sets athletes (from all sports) apart from non-athletes it is basic strength.

This month Endurance Corner is addressing limiters, with the idea that there may be a key skill or weakness that is holding back your best performance. We each vary in our specific physical limiters, but the most common limitation we all face in performance may be the ability to focus for extended periods of time. As Roy Baumeister and John Tierney discuss in their enlightening new book "Willpower: Discovering the Greatest Human Strength", the energy to exert self-control, one of the most valuable human traits, is easily exhausted.

I realized today that I have had my period (menstruation) for almost 30 years of my life. Every three weeks. Sixteen per year for three to four days. 480 times in 30 years. A minimum of 1440 days. I have used tampons for at least three years of my life. When a girl is born she should automatically receive stock in a manufacturer of women's personal hygiene items.

Since this is “define your limiters” month at Endurance Corner, I thought this would be an appropriate topic to discuss. Please note, I am not a medical professional. The info I am sharing is personal experience only with periods, long course racing and training.

When assessing your limiters for the upcoming 2012 season you may find that the solution is not as obvious as you think. Often, the solution to improving upon a limiter comes from an aspect of your life that you hadn’t even considered.

You've made it through the holidays and into the new year. You're fired up looking at the 2012 races; scheduling, planning and getting into your training plan for 2012 summer events.

Triathlon is an endurance event, no matter what distance you choose. From a one-hour to 17-hour race, you are asking yourself to race for a long time. This kind of racing take strength, it takes endurance, and most of all it takes a lot of conditioning. If you've frequently raced long and for a number of years it's easy to get sidelined into only going slow, long, easy.

If you find yourself getting "slow," remember there needs to be a certain amount of speed and power in your plan all year.

by Gordo Byrn

Qualifying for Kona requires a lot of work and, even if you have all day to train, smart overload is an effective way to get better.

Athletes can waste a lot of energy worrying about the structure of their training plan. Prove that you can do the work before you worry about the structure.

One of the best ways to improve at almost anything is to work the weakest link within the set of skills required to be good. For triathlon, we tend to keep things simple and focus on swim, bike and run. That seems easy enough, but before we put the bike away for a couple of months and set off for 50 mile run weeks, are we actually sure what makes up our true limiter?

As running was my gateway into triathlon, I struggled with both swimming and cycling. The former limited by technique and stiff ankles, the latter was simply hard. Cycling hurt and not in a good way. There was a faint masochistic pleasure in running hard, but it was lacking on the bike. My first few races followed a template of losing time in the water and time on the bike and then chasing on the run. While I could hunt down a lot of places in the final leg, cycling held me back. It took a number of years to truly address this limitation and raise my bike performance to match my run.

A number of years ago I was sitting around after a race chatting with a few people. The conversation trended towards upcoming events and someone asked my buddy what he needed to work on before the next race.

“Everything. I need to get better at everything.”

Everyone chuckled, but I always appreciated that answer.

The topic of the month here at EC is limiters. When most athletes think about limiters, they think in and around the qualities that go together to make up their events. If Johnny Kona has a functional threshold of 320W and yours is 280W then you might consider that a limiter to your event specific goals. Perhaps it is, however, January is not the time to be thinking about these event specific qualities. January is the time of year to consider some of the more basic and often ignored qualities that go together to make up the qualities that might eventually limit your performance in your specific event.

November's theme at Endurance Corner was recovery. We heard about a variety of issues related to both workout recovery and off-season recovery.

As endurance athletes, we’re interested in measures of recovery -- and particularly those measures that are quantifiable and might help guide our training schedules. Two such measures are the resting heart rate and heart rate recovery (HRR).

Limiters in sport can be a challenge to train and strengthen. That makes sense because it’s often more fun to do things in areas where we already excel, especially in groups. But in ironman, it is essential that an athlete avoid having a limiter that comprises half of the race.

If we leave out ironman athletes who live in flat lands, a common cycling limiter is seen when comparing hilly threshold power to flat, aero threshold power.

Six years ago I fell in love with triathlon during my first race. I still remember it. The swim was in this murky, scummy pond in the middle of a horse racing track. I remember thinking if I don’t die from a systemic infection (not to mention chemical exposure), I may actually like this sport.

Fast forward to today and my love affair with triathlon continues.

For a long time, some of my limiters have been sugar cravings and a somewhat unhealthy diet. In reflecting on the reason why I started to do triathlon a few years ago everything was about looking good naked. It seems like it is difficult to stay on a healthy diet for a lot of athletes. I can still remember when my good friend Jonas Colting told me, “Jan you are fat.” It still hurts, but he was right.

I have been thinking a lot as I chat with friends and athletes about new year goal setting. There needs to be a direct responsibility for your results. Reaching goals doesn't come by accident. It comes from clear planning and a real connection with what it takes to achieve those goals.

Remember that the role of the coach can be to heal an athlete to the point where they don’t need sport any more.  – Bobby McGee

Recently, I was brainstorming with a buddy about a sabbatical planned to start a year from now. My initial thinking was I’d repeat past patterns and head to the Southern Hemisphere and train big. In the spring, I would emerge and rip the legs off my competition!

Chase Hooley from BTB Sunglasses and the BTB Foundation asked us to help spread the message about testicular cancer.

Read on to learn more about the risks and symptoms for this highly treatable disease.

Here's part two of some of the most popular articles from 2011, along with some of our favorites that you may have missed when they were first published.

Endurance Corner is going to take a brief hiatus from publishing new content for the rest of 2011, but we don't want to leave you hanging. Over the next few days, we'll share a recap of some of our most popular articles from the past year, along with a few gems you may have missed.

We'll be back in January with all new content to help you address your limiters and set yourself up for a great season.

To wrap up the year, we asked some of the EC writing team to share some of the things that worked for them this season and the things that they'll be passing on in the future.

by Gordo Byrn

Three things stand out from the last year.

The first is an example of what we’re up against in terms of our competition for Kona slots.

In May, one of the athletes that I coach, Ron Ottaway, broke his hip. Heading into surgery, he sent me an email asking my thoughts on how this might impact his chances for a slot at Ironman Arizona.

The injury was a tough one and Ron’s still not back to full function. He did, however, win his age group and qualify for Kona at Ironman Arizona.

More than winning, my buddy is an example of the best in sport –- there’s no quit in Ron Ottaway!

Ron is 74 years old.

When it comes to selecting a race, there are a number of factors that will influence your decision. Generally speaking, for Kona qualification, big guys need to do flat courses and skinny guys should do hilly events. If you want to get a PB go to Roth. That’s all I’ll say about the competitive side of things, as going any further is leading me outside of my knowledge base and is better discussed by the more qualified people on this website.

For me, ironman is more than just qualifying for Hawaii or getting under a magical time.

As I planned the coming season I couldn't resist -- from my first race in May through the last in September, I've lined up four ironmans and a 70.3 for the year ahead. After a lighter season -- admittedly consisting of two ironmans and Long Course Worlds -- I needed to race again. I'm not convinced this is a route to my best performances, but that's not my only motivation; I enjoy racing and I enjoy racing long.

The majority of athletes focus on one or two events per year so naturally most advice on planning seasons does the same. For those of us who want to race more it can be a process of trial and error; here are some of my thoughts from planning race heavy seasons.

The topic of conversation this month at EC is race selection. Now is the time of year that athletes are filling in their calendars and deciding what races will occupy 2012.

I don’t think it’s unfair to say that deciding which races best suit your strengths is a bit of a mystery for most.

As you face the winter you might be starting to look at areas you can work on that you aren't able to target during your race season.

Through my 20s I spent many hours in the gym learning all kinds of dynamic strength programs for different sports. Most of them were explosive sports, but as I ventured into the endurance world I took the time to learn the value of gym strength in training for the long stuff.

It’s currently dumping snow in Boulder while I'm writing this, so it’s an opportune time to start daydreaming about next season. Even if it’s not snowing in your neck of the woods, you are probably getting antsy sitting on your hands waiting for next season to come around.

Ideally, this might be a time to start giving some thoughts to what races you want on your calendar, but with the popularity of Ironman races, your key races of the season might have already been decided. Nevertheless, whenever you decide on adding a (key) race to your calendar, you should use the following suggestions to narrow your choices down.