By Steve Auchterlonie
The Pedal Stroke Part 2
The biggest challenge for me in writing these articles is how to condense them without losing valuable content. I am unable do it with this one, so a compromise is needed. The compromise will be two shorter articles: the first exploring climbing and the second (to follow timely) investigating sprinting. In the near future, a final article will explain how to pedal efficiently
The Pedal Stroke Part 1, explained that measured power can be separated into Radial and Tangential directions, with radial power not moving the bike (wasted energy) and tangential power moving the bike (efficient). Part 1 also documented that an efficient pedal stroke “saves” the cyclist’s legs for the key moments in a race/ride. Heckler in bicycle kit yells from the peanut gallery, “Doesn’t Steve drive a Prius?!! The Prius is very efficient but definitely not a performance machine.” “Where is the proof that an efficient stroke improves performance?” Steve Replies, “Dude, wear normal clothes off the bike!! However, you pose a fair question. Here are both empirical and actual ride results:
- Empirical – The following examples are clients of mine in the last six months:
a. Client A – solid racer at 2014 Joe Martin Master’s level. He came to me two weeks before 2015 JM race and said, “Let’s make the change because I’m lucky to make the top 20 right now.” Made position changes to enable an efficient pedal stroke two weeks before 2015 JM and finished on podium, plus 2nd place at state road race in his division.
b. Client B – talented master’s racer with inconsistent results. Since making change in position to enhance an efficient pedal stroke one month ago, he has won state road race in his division and the masters road race at the Roger’s Festival.
c. Client C – back of the pack master’s road racer from Belize. Started change to pedal stroke in Spring while visiting his son at UofA, he went home this summer and has finished in top six in two major road races, and won time trial after finishing last place one year ago.
d. Client D – first year racer with talent. Made changes in position to enhance efficient pedal stroke two or three weeks ago. In last week he has shared with me that he won a city limit sign against an elite group, set the KOM on the Devil’s Den to Winslow segment, and produced multiple PRs and trophies at Tuesday’s worlds.
I could provide more examples but will limit it to four for this article. It’s important for me to note that each of these racers put in hard work on and off the bike to achieve these accomplishments, but each one will tell you that the key change is the pedal stroke.
- Ride Data/Results – making the selection in races/rides comes down to climbing and sprinting. The following data/results are provided to demonstrate how an efficient pedal stroke improves performance when climbing.
a. Climbing – Within a narrow timeframe one day so weather conditions were constant, I conducted the following intervals up the hill on School St. from Martin Luther King to the 2nd light at the top, next to the square. This is a 0.6 mile climb at a steady 5% grade. The goal was not to PR the hill. Instead, I ran it at two different solid efforts – alternating one stomping down and one pedaling efficiently. Then, I made a good effort at the end while pedaling efficiently. Here are the results:
- Time Gaps – critical in racing, right. If you are gapped off the back on a climb then the race is gone for you. How much gap is too much? In my experience, 50 yards (150 feet) off the back is too much. At climbing speeds of 12-15mph, the velocity is approximately 20 feet/sec. So, a 150 foot gap is 7.5 seconds. The gap between intervals 1 and 2 is 7 seconds or 140 feet. The gap between intervals 3 and 4 is 3 seconds or 60 feet. The hard effort in interval 5 is 18 seconds ahead of interval 4, or 360 feet!!
- Stomping vs Efficiency – the first comparison is between intervals 1 and 2. You will note that interval 2 averaged 18w more than interval 1. This is not a fair comparison. Is it? I can share that it felt like the same effort but I had a hard time holding the power down while pedaling efficiently, eventually giving up and just going with “feel” during later part of the interval. You should also note that the cadence is 10% different between the 2 intervals. More on those points later. Comparing intervals 3 and 4 shows that both averaged 306w, yet the time was 3 seconds (60 feet) faster for interval 4. This is a significant gap and can only be explained by the efficient interval producing more tangent power than the stomping interval.
- Pedal Force – what is that again? As explained in the part 1 pedal stroke article, power is calculated by measuring the force (as measured by several methods: pedal/crank arm/crank spyder/rear hub) and multiplying it by the acceleration of that component. The intervals were run using a Pioneer powermeter which measures and reports the actual force produced, in newtons. Force is produced by the legs and leads to fatigue. Thus, measured force through the entire pedal stroke documents the level of effort to produce the power. Comparing intervals 1 and 2, it appears that the stomping interval 1 required less total force. This conclusion is not accurate. Remember, interval 2 produced 18 watts (6%) more power and the cadence was 10% lower. Force is directly proportional to power and inversely proportional to cadence. Thus, if we adjusted to compare “apples to apples” then interval 1 = 2014 N x 1.06 x 1.1 = 2348 N, whereas the efficient interval 2 required 2088 N. Simply, interval 2 was over 10% less demanding to produce the same power level. This holds true comparing intervals 3 and 4, with the more efficient pedal stroke saving over 10% effort to produce equal power.
- Subjectively, it was “easier” to produce the power level when pedaling efficiently. This explains why I could not “hold down” to 250w on interval 2, while pedaling efficiently.
- What was the purpose for interval 5? Efficient intervals 2, 4 and 5 document a) a higher efficiency can be held at wide ranging power efforts, and b) the pedal force required to produce power is linearly related: a 10% increase in efficient pedal force will produce a 10% greater power level. Thus, reducing fatigue by pedaling efficiently “saves” the legs to produce race winning efforts when needed.
- Finally, points 1 through 5 document that performance is increased using an efficient pedal stroke because it requires less force to produce a power level. When it is time in a race/ride to make that top effort, a cyclist will produce their maximum force whether pedaling efficiently or not. A higher power level will be produced using the more efficient pedal method.
Both empirical and field data/results have been provided to demonstrate that a race/ride performance is enhanced using an efficient pedal stroke, when climbing. Are you ready for the surprise behind the efficient pedal stroke? “Johnny, what’s behind door number 3?” drum rolllllllllllll…”It’s called hard work.” Ask my clients who have started the learning curve. Your hamstrings and hip-flexors have been on vacation and they will be speaking to you…loudly. Significant improvement can happen in a short timeframe but only with dedication.
To get faster, pedal harder and more efficiently.
To find out more about the services Steve offers at Cycling Performance Lab you can contact him at: