View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Research Online @ ECU Edith Cowan University Research Online ECU Publications 2013 1-1-2013 Pedal force effectiveness in cycling: A review of constraints and training effects Rodrigo Bini Patria Hume James L. Croft Edith Cowan University, [email protected] Andrew Kilding Follow this and additional works at: https://ro.ecu.edu.au/ecuworks2013 Part of the Sports Sciences Commons Bini, R., Hume, P., Croft, J. L., & Kilding, A. (2013). Pedal force effectiveness in cycling: A review of constraints and training effects. Journal of Science and Cycling, 2(1), 11-24. Availablehere This Journal Article is posted at Research Online. https://ro.ecu.edu.au/ecuworks2013/891 J Sci Cycling. Vol. 2(1), 11-24 REVIEW ARTICLE Open Access Pedal force effectiveness in Cycling: a review of constraints and training effects Rodrigo R Bini1, 2, Patria Hume1, James Croft3, Andrew Kilding1 Abstract Pedal force effectiveness in cycling is usually measured by the ratio of force perpendicular to the crank (effective force) and total force applied to the pedal (resultant force). Most studies measuring pedal forces have been restricted to one leg but a few studies have reported bilateral asymmetry in pedal forces. Pedal force effectiveness is increased at higher power output and reduced at higher pedaling cadences. Changes in saddle position resulted in unclear effects in pedal force effectiveness, while lowering the upper body reduced pedal force effectiveness. Cycling experience and fatigue had unclear effects on pedal force effectiveness. Augmented feedback of pedal forces can improve pedal force effectiveness within a training session and after multiple sessions for cyclists and non-cyclists. No differences in pedal force effectiveness were evident between summarized and instantaneous feedback. Conversely, economy/efficiency seems to be reduced when cyclists are instructed to improve pedal force effectiveness during acute intervention studies involving one session. Decoupled crank systems effectively improved pedal force effectiveness with conflicting effects on economy/efficiency and performance. Keywords: pedal forces, pedaling technique, cycling performance, workload, pedaling cadence, body position Contact email: [email protected] (RR. Bini) strategies may not be fully translated into better force effectiveness. However, cyclists can improve power 1 Sport Performance Research Institute New Zealand, Auckland output if they improve force effectiveness, but they University of Technology, Auckland, New Zealand cannot improve power output exclusively by 2 Laboratório de Pesquisa do Exercício, Universidade Federal do Rio improvements in pedaling technique (Bini and Grande do Sul, Porto Alegre, Brazil Diefenthaeler 2010). For a similar pedaling technique 3 School of Physical Education, Otago University, Dunedin, New (e.g. focus on pushing down forces applied at the Zealand downstroke phase) power output can be improved by __________________________________________________ increasing magnitude of force application (assuming Received: 19 November 2012. Accepted:18 April 2013. similar directions of the force). However, changing technique to a more circling action (i.e. greater force effectiveness for similar magnitude of forces) power Introduction output can be improved, but only because force During cycling, lower limb movement in the sagittal effectiveness is improved. In a mechanical perspective, plane is constrained to a circular path by the geometry applying pedal forces perfectly perpendicular to the of the bicycle (i.e. cranks and pedals). Within these crank in the direction of crank motion (force constraints the cyclist can vary pedaling technique by effectiveness equal to 100%) is only possible if a changing the kinematics of their lower limbs (thigh, perfect circling action is performed by the cyclist. shank and foot) and the activation of muscles. Existing evidence is conflicting regarding the Technique in cycling can be assessed through relationship between pedal force effectiveness and measurement of joint kinematics (Bini et al. 2010; performance in cycling. Most research suggests that Chapman et al. 2008b; Hasson et al. 2008) and muscle when the effectiveness of the force applied on the pedal activation patterns (Bini et al. 2008; Candotti et al. is optimized, the economy/efficiency (i.e. ratio between 2009; Dorel et al. 2009b). Alternatively, pedal force mechanical energy produced and physiological energy effectiveness (ratio of the force perpendicular to the demand) is reduced (Korff et al. 2007; Mornieux et al. crank and the total force applied to the pedal) has also 2008). No research has been conducted to quantify the been used as a gold standard measure of technique in relationship between symmetry in pedal forces and cycling (Dorel et al. 2009a; Dorel et al. 2009b; Rossato performance. We chose to review the use of pedal force et al. 2008). However, there has been criticism recently effectiveness during cycling as pedal force systems are regarding using pedal force effectiveness exclusively now commercially available to monitor cycling training for feedback as pedal force effectiveness may not and performance. Therefore, it is important to analyze provide a full representation of pedaling technique of what we know and what we still need to learn in terms cyclists (Bini and Diefenthaeler 2010). Pedaling of pedal force effectiveness to better advise cyclists and technique is probably too complex to be summarized coaches. by force effectiveness alone given that technique © 2013 Bini; licensee JSC. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. J Sci Cycling. Vol. 1(2), 11-24 Bini et al. The purpose of this review was to summarize current pedal force measurements. knowledge on pedal force effectiveness during cycling and how it is affected by task constraints such as Results workload, pedaling cadence, body position, fatigue and Most studies measuring pedal forces have been cycling ability. Limitations and benefits of measuring restricted to one leg but a few studies have reported and using pedal force effectiveness feedback bilateral asymmetry in pedal forces. Pedal force exclusively are discussed throughout the article. effectiveness is increased at higher workload level and Interventions to improve force effectiveness and reduced at higher pedaling cadences. Changes in saddle cycling performance are also considered to identify position resulted in unclear effects in pedal force interactions between technique training and effectiveness, while lowering the upper body reduced performance. pedal force effectiveness. Cycling experience and fatigue had unclear effects on pedal force effectiveness. Methods Augmented feedback of pedal forces can improve pedal Academic databases (MEDLINE, SCOPUS, ISI Web force effectiveness within a single training session and of Knowledge, EBSCO, and GOOGLE SCHOLAR) after multiple sessions for cyclists and non-cyclists. No were searched for peer-reviewed journals, books, differences in pedal force effectiveness were evident theses, and conference proceedings since 1960 with the between summarized and instantaneous feedback. keywords pedal force effectiveness, workload, pedaling Conversely, economy/efficiency seems to be reduced cadence, saddle position, cycling, fatigue, and when cyclists are instructed to improve pedal force symmetry. Articles were not included when they could effectiveness during acute intervention studies not be retrieved without at least an English abstract. involving one session (Korff et al. 2007; Mornieux et Journal articles (82), book chapters (4), and conference al. 2008). Decoupled crank systems effectively articles (10) were included in this review based on improved pedal force effectiveness with conflicting exclusion criteria of articles that were not related to effects on economy/efficiency and performance. Table 1. Scientific papers reporting different systems to measure the force applied on the pedals during cycling. Reference Sensor type Force components and moments Cleats type Application Guye (1896) PressureA Normal (Fz) No cleats UnknownB Sharp (1896) PressureA Normal (Fz) No cleats Laboratory Hoes et al. (1968) Strain gauge Normal (Fz) Toe clips Laboratory Sargeant & Davies (1977) Strain gauge Normal (Fz) Toe clips Laboratory Dal Monte et al. (1973) Strain gauge Normal (Fz) and anterior-posterior (Fx) Toe clips Laboratory Normal (Fz), anterior-posterior (Fx) and Hull & Davis, (1981) Strain gauge Toe clips Laboratory medio-lateral (Fy), and related moments Harman et al. (1987) Strain gauge Normal (Fz) and anterior-posterior (Fx) UnknownB Laboratory Newmiller et al. (1988) Strain gauge Normal (Fz) and anterior-posterior (Fx) Clip in Laboratory Normal (Fz), anterior-posterior (Fx) and Toe clips and Broker & Gregor (1990) Piezoelectric Laboratory medio-lateral (Fy), and related moments Clip in Álvarez & Vinyolas (1996) Strain gauge Normal (Fz) and anterior-posterior (Fx) Clip in Road Normal (Fz), anterior-posterior (Fx) and Boyd et al. (1996) Strain gauge Clip in Laboratory medio-lateral (Fy), and related moments Normal (Fz), anterior-posterior (Fx) and Nabinger et al. (2002) Strain gauge Clip in Laboratory medio-lateral (Fy), and related moments Reiser