I am a big time data geek. Not in a casual "I like numbers" kind of way; more in an "I love physics" kind of way. So I definitely get into the data when I review my athletes’ training logs, and I enjoy talking with them about the data - how to interpret it, what to watch, and what to ignore. Through my own conversations and too much time spent in Facebook groups, I’ve noticed that often athletes are paying attention to the wrong metrics. Here’s my advice on what matters and what doesn’t:
Two Metrics You Can Stop Watching
1. VO2 Max
For real, this doesn’t matter. A few of the newer GPS watches will estimate your VO2 based on your workout data, and notify you as they think it changes. As a result, I’ve seen lots of conversations in Facebook groups about “is my VO2 Max accurate” and “why isn’t my VO2 Max changing?” My response: Who cares? VO2 Max is a metric that is largely driven by your personal physiology and genetics, is not going to see dramatic changes once base fitness is achieved, and - most importantly - cannot be used to direct training or racing. No one has a training run targeted at X% of their VO2 Max, and you definitely aren’t pacing your race off your VO2 Max. There is also plenty of evidence showing that grit and determination play an equally important role in race results as athletic potential (e.g., VO2 Max). So it really, really doesn’t matter what that number is.
2. CTL (Chronic Training Load, a.k.a. Fitness)
Athletes *love* to stare at their Performance Management Chart in TrainingPeaks. (Confession: myself included, when I take my coaching hat off.) It’s really easy to get totally flipped out about your CTL. Is it high enough? Is it climbing fast enough? Why is mine lower than hers? When I put my coaching hat back on, I remember that the CTL measurement is NOT the final judge and jury on my fitness. It’s a single piece of data based on individual workout training stress calculations that also have some inherent flaws, so the absolute number - and even the ramp rate - really isn’t as meaningful as you think. If you have a well written training plan with progressive increases in duration and/or intensity, then you can rest assured that your fitness is improving and stop staring at that darn chart.
Two Metrics You Should Care About
1. Time in Zones
Zone 2 (endurance level) training is a critical piece in improving your aerobic capacity. Training in this zone increases your body’s fuel efficiency at sub-threshold effort levels and increases fatigue resistance, all while minimizing the training stress on your body. Because of this, no matter if you’re a short-course or long-course athlete, you should spend roughly 80% of your training time in Zone 2. Take a look at your Time In Zones charts, particularly for bike and run - do you have that covered, or are you putting in too much time at higher intensities, particularly Zone 3? If so, a shift in your training balance can provide the improvements that have been eluding you.
2. EF (Efficiency Factor)
The best way to spot fitness improvements without subjecting yourself to those horrible 30 minute time trials is by watching your EF. An increase in EF across workouts signals either an improvement in pace or power at a constant heart rate, or a lower heart rate for constant pace or power, also known as: increased fitness. In other words, if you’re running faster than a month ago at the same heart rate, you’re pace zones have increased and your race paces have all improved. And THAT is what everyone is after, isn’t it?