Question: Would a power meter help me maintain steady energy expenditure throughout time trials and triathlons? Could I just watch the monitor, ride at a pre-determined wattage and thus be sure that I performed at optimum intensity? What about in road races? — Barry M.
Coach Fred Matheny Replies: Power meters are often touted as great pacing aids for time trials.
Let’s say you know from training the wattage level you can sustain for the race distance. During the event, you’d simply set the monitor to display average wattage and stay within 10 watts of that figure from start to finish.
In theory, this means you’ll always be at your maximum sustainable intensity for the distance. You won’t start too hard (a common mistake) and then slow significantly near the end. And you won’t go too hard on climbs, thus risking blowing up and being unable to maintain speed on the downhills and flats.
That said, I don’t find power meters to be very useful in this way.
TTs aren’t really steady-state efforts unless the course is dead flat. Even then, there will be a turnaround and perhaps headwind sections. When the going gets tough, you have to venture above your lactate threshold for short periods, then back off slightly to recover.
So to maintain a given average wattage, you need to know how much above the average you can go on climbs or into headwinds but still recover sufficiently when conditions allow. This is why I think power meters are less effective in time trials than perceived exertion.
As for road races, forget about it. It’s fine to race with a power meter and record the data for later analysis. And it’s a great training tool to help you learn how deeply you can dig on short climbs and still have enough left to recover. But during races, you should be racing, not looking at flashing numbers on your handlebar.