Ethan Caldwell

I remember the first time I looked at my heart rate monitor during a threshold run. The watch read 185 beats per minute, and I immediately panicked. According to the standard formula, my max heart rate should have been 180. Was something wrong with me? Had I pushed too hard? That was five years ago, … Read more

What is VO2 max? It is the maximum amount of oxygen your body can use during intense exercise, measured in milliliters of oxygen per kilogram of body weight per minute (ml/kg/min). This single number tells you how efficiently your heart, lungs, and muscles work together to produce energy. For triathletes training for events like the … Read more

Understanding your lactate threshold is one of the most valuable things you can do as a triathlete. This single physiological marker tells you more about your race potential than almost any other metric. Lactate threshold is the exercise intensity where your muscles produce lactate faster than your body can clear it. Once you cross this … Read more

Understanding what is a good VO2 max by age can transform how you approach triathlon training. I have spent years tracking this metric across athletes from 25 to 65, and the data tells a compelling story about cardiovascular fitness and endurance potential. Your VO2 max represents the maximum amount of oxygen your body can utilize … Read more

Zone 2 training has become one of the most discussed topics in endurance sports over the past few years. I remember when I first heard athletes talking about running “slow to get fast” – it sounded completely backwards. After spending months researching the science and applying it to my own training, I can tell you … Read more

After three years of chasing podium finishes in sprint and Olympic distance triathlons, I hit a frustrating plateau. My swim times stagnated, my bike power would not budge, and my run splits felt stuck in quicksand. My coach pulled up my training data and asked one simple question: When was the last time you trained … Read more

You finish a training run feeling completely exhausted. Your legs are heavy, your breathing is ragged, and you wonder why you’re not getting faster despite all this effort. I have been there. After coaching triathletes for over a decade, I see this pattern constantly. Athletes training too hard, too often, and wondering why their race … Read more

If you’ve spent any time around endurance athletes, you’ve probably heard someone drop their VO2 max number like it’s a badge of honor. “I’m sitting at 52 right now,” they’ll say, as if that single digit explains everything about their fitness. But what is VO2 max, actually? And why does it matter so much for … Read more

Zone 2 training represents the foundation upon which all endurance performance is built. This low-intensity aerobic training method targets 60-70% of your maximum heart rate, teaching your body to become more metabolically efficient while building the aerobic capacity that powers everything from sprint triathlons to IRONMAN events. After coaching hundreds of athletes preparing for events … Read more

I still remember my first brick workout like it was yesterday. I hopped off my bike after a 90-minute ride, slipped into my running shoes, and took three steps before my legs completely betrayed me. They felt like concrete blocks attached to my hips, heavy and unresponsive, refusing to move at anything resembling a normal … Read more