Bike Cadence Test
Main Set: Find a repeatable stretch of road or on the trainer. Complete 3 x 10 minute efforts @ Z3 wattage....or about half ironman intensity. Important that this is a repeatable effort, not a TT effort. After the first interval, note your average power. It's key to keep the wattage constant so the average wattage is the same for all 3 intervals. Wear your heart rate monitor. Only variable you want to change is your cadence. If on the road, then use speed as the constant.
1st Interval @ 88 - 93 RPM
2nd Interval @ 80 - 86 RPM
3rd Interval @ 72 - 78 RPM
Allow 6-7 minutes of easy riding in between. If you are on the road and need more time to get back to your starting point, that's fine. - Don't spin for this. Keep wattage really low on recovery and let your body recover as much as possible.
Pay attention to which cadence feels the easiest for you and allows you to stay the most relaxed.
Take a look at heart rate for all three efforts. Which one is the lowest?
Make sure your speed/wattage was the same for all three efforts. If you see a lower heart rate at a lower cadence, then this is likely the most efficient range. Don't rely on one test. Try longer intervals as well. Try it climbing too. Reverse the order on the intervals.
If the lower RPM riding is more efficient, but you have not raced this way, then be sure to get in plenty of big gear work and be sure to spend time riding below this RPM.
If you are training for an Ironman or half Ironman, consistency is your best friend. It's not about smashing two or three session and then barely make it through the week. Training should be a gradual progression of workload, repeated week after week. There are no secret sessions that will all of a sudden make you better. Work and more work is the recipe. Target all of the systems you'll need to tap into on race day. Ironman is a strength-endurance sport so it's not just about miles. Sure miles have their place, but you have to get strong.
Race Faster and Stronger
Download the Foundations of Performance pdf. and find out how you can push the bike, look forward to the run, and finish with a performance you are proud of.