It has been suggested that improving pedaling technique is one way of improving efficiency and performance in endurance cycling (LaFortune & Cavanagh 1983). Over the past few decades, pedal force effectiveness (PFE) has become one of the most used measures in the scientific and cycling communities to measure the quality of pedaling technique. PFE measures the percentage of total force that is applied perpendicularly to the crank. A pedaling action where pedal forces are applied perfectly perpendicular to the crank around the entire pedal cycle would be considered 100% effective. This would only be possible if the cyclist performed a perfect circling action.
As is often the case in cycling an entire industry has been built around the notion of PFE. A quick search of the Internet will uncover numerous cycling coaches, bike fitters and spin class instructors as well as educational tools that provide pedaling technique instruction along with the promise of improved performance. In addition, over recent years there has been a proliferation of commercially available force and power measuring devices that provide some type of PFE measure (i.e. wattbike, CompuTrainer ®, bikefitting.com). These systems provide the rider with visual feedback of pedal forces during the entire pedal stroke allowing the cyclists to improve their ‘technique’ and generate ‘ideal’ force application through the entire pedal stroke.
However, the research has shown that in practice the force application of cyclists is different from the ‘ideal’ force application discussed above. A number of studies have reported the force profiles of cyclists (Coyle et al. 1990; Hug et al. 2008; Korff et al. 2007; Mornieux et al. 2008) and non-cyclists (Mornieux et al. 2008) and found that the vast majority of propulsive forces are generated during the 12 to 6 o’clock portion of the pedal stroke (the propulsive phase) whilst minimal to negative propulsive forces were reported during the 6 to 12 o’clock portion (the recovery phase). In addition, studies that have examined individual variability in pedaling force profiles found greater variability between individuals during the upstroke compared to the down-stroke (Coyle et al. 1990; Hug et al. 2009). In other words, pushing during the down-stroke is a fairly ubiquitous practice however the choice to apply effective force during the upstroke was much more an individual phenomenon.
Given the apparent divide between the ‘ideal’ pedaling action and practice, there exists a possibility that cyclists can increase performance by improving pedaling technique. The purpose of this discussion is to share some insights of my reading of the published literature as to whether improved PFE results in better performance.
In an extensive review paper Bini et al. (2013) found that the research conclusively shows that when cyclists are given visual feedback of pedal forces and/or verbal instruction that they can improve PFE. Specifically, they reported that research had found that adaptations can occur in both cyclists and non-cyclists and that these adaptations can be relatively long lasting and meaningful. However, despite the relative ease and magnitude at which PFE can be improved they found that there is little evidence to show that it results in increased efficiency. In fact, a number of studies found that when cyclists were instructed to pull during the upstroke efficiency actually decreased.
In addition, the research suggests that the more experienced the cyclist the less likely there is to be a relationship between PFE and efficiency. In a comparison between elite cyclists and non-cyclist who were asked to pull up on the pedal during the upstroke, Mornieux et al. (2008) found that efficiency reduced by 9% in elite cyclists and 3% in non-cyclists. Similarly, in a simulated 40 km time-trial of competitive cyclists, Coyle et al. (1991) found that cyclists who achieved better performance where the ones who had lower PFE but were able to generate higher peak torques by applying larger vertical forces during the down-stoke. In other words, they were better at pushing. These researchers have proposed that the inverse relationship observed between PFE and efficiency suggests that within the context of steady-state submaximal cycling, the lower limb extensor muscles may be more efficient power producers than the flexor muscles.
Given the weight of evidence it is highly unlikely that PFE is related to efficiency in endurance cycling. However, other research provides an insight into how the cyclist might go about approaching the puzzle of optimising pedaling technique.
Firstly, a number of researchers have found that PFE increases with load (Ericson & Nisell 2008; Sanderson 1991) to name a few. This evidence highlights an important point. As power demand increases it is likely that cyclists tend to increase the force contribution of the hip and knee flexors in order to recruit a larger number of muscles to meet the prescribed power demand (Bini & Diefenthaeler 2010). Intuitively this makes sense. In efforts requiring maximal power the cyclist will try to generate propulsive forces through as much of the pedal stroke as possible (e.g. during sprinting).
Secondly, there is some evidence to suggest that better PFE at the top of the pedal stroke may improve efficiency/performance. Leirdal & Ettema (2011) found that dead centre size (DC), which effectively captures force effectiveness at the top and bottom of the pedal stroke, was more closely related to efficiency than PFE. Some of the more interesting research though has come from Blake et al. (2012). They found evidence to suggest that a reduction in ankle range of motion along with prolonged tibialis anterior activation during the first portion of the down-stroke as well as early activation of the hip and knee extensors may result in greater efficiency. It is not surprising then that research has also shown that when power output is increased, both cyclists and non-cyclists improve PFE around the top of the pedal stroke (Sanderson 1991). That said, further research is needed before any definitive conclusions can be made.
The practical implications of the evidence presented are refreshingly simple, particularly as it relates to where in the pedal cycle force should be applied. A preferred pedaling technique, that has been shown to largely resemble a pushing action, is as efficient as any other. And moreover, this preferred pedaling action is likely to organically adapt to the power demands placed on it. Thus, for the most part, the cyclist should try to avoid manufacturing any particularly pedaling action and allow intrinsic feedback to the neuromuscular system to influence technique. However, there is one caveat. There is some evidence to suggest that the sooner the cyclist starts the propulsive pushing motion at the top of the stroke, particular under heavy loads, and the more stable the foot, the better.
Bini R, Diefenthaeler F. (2010) Kinetics and kinematics analysis of incremental cycling to exhaustion. Sports Biomechanics 9: 223-235
Bini R, Hume P, Croft J. (2013) Pedal force effectiveness in cycling: A review of constraints and training effects. Journal of Science and Cycling 2(1): 11-24
Blake O, Champoux Y, Wakeling J. (2012) Muscle coordination patterns for efficient cycling. Medicine & Science in Sports & Exercise 44(5): 926-938
Coyle E, Feltner M, Kautz S, Hamilton M, Montain S, Baylor A, Abraham L, Petrek G. (1991) Physiological and biomechanical factors associated with elite endurance cycling performance. Medicine and Science in Sports and Exercise 23: 93-107
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Korff T, Romer L, Mayhew I, Martin J. (2007) Effect of pedaling technique on mechanical effectiveness and efficiency in cyclists. Medicine and Science in Sports and Exercise 39(6): 991–995
Hug F, Drouet J, Champoux Y, Couturier A, Dorel S. (2008) Interindividual variability of electromyographic patterns and pedal force profiles in trained cyclists. European Journal of Applied Physiology 104: 667-678
Lafortune, M. A., and Cavanagh, P. R. (1983). Effectiveness and efficiency during bicycle riding. In H. Matsui, and K. Kobayashi (Eds.), Biomechanics VIII-B (pp. 928–936). Champaign: Human Kinetics.
Leirdal S, Ettema G. (2011) Pedaling technique and energy cost in cycling. Medicine and Science in Sports and Exercise 43: 701-705
Mornieux G, Stapelfeldt B, Collhofer A, Belli A (2008) Effects of pedal type and pull-up action during cycling. International Journal of Sports Medicine 29: 817-822
Sanderson D. (1991) The influence of cadence and power output on the biomechanics of force application during steady-rate cycling in competitive and recreational cyclists. Journal of Sports Sciences 9: 191–203