Have you plateaued in your running or cycling? Do you do a majority of your training in "Zone 3", 70 to 80 percent of maximum heart rate? This could be the reason why.
Zone 3 workouts provide some great benefits such as increasing cardio-respiratory capacity, pace training and even sport-specific strength. But the downside of doing most of your workouts like this is that your body never learns how to go fast.
More: Training Zones Explained
I have many athletes say things like "I can't run faster than 8 minutes per mile in a 10K." I ask what does your training consist of and they typically say "I run 5 to 6 days a week around 6 miles a day at an 8-minute pace."
There is the answer to the question. By this type of training, your body becomes very good at maintaining this pace, but has never been trained to do anything different.
By doing short, fast intervals in Zone 4 (80 to 90 percent of max heart rate) with recovery, you train to go faster than race pace which your body will then adapt to making you faster. This type of training also increases lactate threshold, which is the level of where your body can no longer remove the lactate acid that it is producing.
On the other side, many athletes feel their time is wasted if they train in Zone 2 (60 to 70 percent of max heart rate) as it seems too "easy." However, this zone is the best at teaching your body to metabolize fat as the primary fuel. "Recovery" zone also improves the ability for your heart to pump blood and your muscles to utilize oxygen.
Zone 2, also referred to as LSD (long, slow, distance), helps build distance for long runs or rides and the muscles learn how to "fire" for increased time on your legs or in the saddle.
Try switching to some of the workout examples below to end a plateau and achieve new personal bests.
Run: 6-mile run with the first quarter of miles 2 to 5 at 10 seconds faster than 5K pace, then the remainder back to Zone 2 efforts.
Bike: 10-minute warm-up, then 5 minutes at Zone 4 or 110 percent of FTP (if tracking watts), then 3 minutes easy spin. Repeat this effort 5 to 7 times and then a 10-minute easy spin cooldown.
Also, don't be afraid to go out and run or ride at a conversation pace for a couple hours and enjoy being outside and maybe even stop with friends for coffee. Trust me, there is a lot of benefit to this type of workout, such as teaching your body to burn fat as fuel as well as time to work on technique.
Search for your next triathlon.