The Effect of Cadence on Shank Muscle Oxygen Consumption and Deoxygenation in Relation to Joint Specific Power and Cycling Kinematics

RESEARCH ARTICLE The Effect of Cadence on Shank Muscle Oxygen Consumption and Deoxygenation in Relation to Joint Specific Power and Cycling Kinematics Knut Skovereng*, Gertjan Ettema, Mireille van Beekvelt Centre for Elite Sports Research, Department of Neuroscience, Norwegian University of Science and Technology, Trondheim, NORWAY * a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 OPEN ACCESS Citation: Skovereng K, Ettema G, van Beekvelt M (2017) The Effect of Cadence on Shank Muscle Oxygen Consumption and Deoxygenation in Relation to Joint Specific Power and Cycling Kinematics. PLoS ONE 12(1): e0169573. doi:10.1371/journal.pone.0169573 Editor: Andrea Macaluso, Universita degli Studi di Roma ’Foro Italico’, ITALY Abstract The purpose of the present study was to investigate the effect of cadence on joint specific power and cycling kinematics in the ankle joint in addition to muscle oxygenation and muscle VO2 in the gastrocnemius and tibialis anterior. Thirteen cyclists cycled at a cadence of 60, 70, 80, 90, 100 and 110 rpm at a constant external work rate of 160.1 ± 21.3 W. Increasing cadence led to a decrease in ankle power in the dorsal flexion phase and to an increase in ankle joint angular velocity above 80 rpm. In addition, increasing cadence increased deoxygenation and desaturation for both the gastrocnemius and tibialis anterior muscles. Muscle VO2 increased following increased cadence but only in the tibialis anterior and only at cadences above 80 rpm, thus coinciding with the increase in ankle joint angular velocity. There was no effect of cadence in the gastrocnemius. This study demonstrates that high cadences lead to increased mVO2 in the TA muscles that cannot be explained by power in the dorsal flexion phase. Received: June 5, 2016 Accepted: December 18, 2016 Published: January 6, 2017 Copyright: © 2017 Skovereng et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. Funding: The authors received no specific funding for this work. Competing Interests: The authors have declared that no competing interests exist. Introduction The external work rate produced during cycling is mainly generated by the muscles spanning the hip, knee and ankle joints [1]. Whereas the large mono articular muscles working over the hip and knee joints are regarded the main power producing muscles (i.e., the gluteus and the vasti), the role of the muscles working over the ankle joint (e.g., the tibialis anterior, gastrocnemius and soleus) are thought to transfer power to the crank and control the foot during the pedal stroke [2, 3]. The relative joint power contribution to the overall external work rate is affected by cadence, with increasing cadence leading to increased knee contribution and decreased hip contribution [4–6]. Contrary, the ankle joint’s contribution to external work rate is unaffected by changing cadence [4, 5, 7, 8]. The outcome at the joint is the result of the work done by multiple muscles, and therefore joint specific power may not provide a complete picture of the power contribution of the individual muscles. Additionally, the ankle movement during the pedal cycle consists of a plantar PLOS ONE | DOI:10.1371/journal.pone.0169573 January 6, 2017 1 / 13 Cycling Kinematics and Muscle VO2 in the Shank flexion phase and a dorsal flexion phase [5] and muscles associated with these two movements (e.g. tibialis anterior (TA) and gastrocnemius(GAS)) could potentially be affected differently by a change in cycling cadence. Furthermore, with regard to the previously mentioned ankle function, there can be other factors, such as range of motion (ROM) and joint angular velocity, that relate to the energy expenditure of the muscles spanning the ankle joint. An increased joint angular velocity at a joint would require the muscles spanning that joint to work at an increased contraction speed. Ankle ROM has been reported to decrease following increased cadence during maximal [9] and submaximal [10] pedalling, minimizing the effect on joint angular velocity [9]. In addition, a reduced ROM has been proposed as a strategy for simplifying the pedalling task by reducing joint angular velocity [9]. Changing cadence requires different movement speeds, and thereby likely affects muscle activation by changing the amount of recruited fast twitch fibres [11]. There are few studies that investigated the effect of cadence on muscle activation in the shank and there seems to be no consensus. Baum and Li [12] found an increased muscle activation with increasing cadence in the tibialis anterior (TA) and Neptune et al., found increasing GAS muscle activity with increasing cadence [13]. These differences could have resulted from the high interindividual variability that has been reported for muscle activity [14]. However, a difference in the amount of activity observed in a muscle does not necessarily mean that that muscle used more energy. Additionally, muscle activation does not distinguish between the various energy systems. Therefore, investigation of the metabolic requirement of individual muscles during exercise can help to elucidate the effect of cadence on the role of the individual muscles. The few studies on the effect of cadence on muscle deoxygenation at a constant power output have reported both an effect [15] and no effect [16] in the vastus lateralis. However, to the best of our knowledge, no study has investigated the effect of cadence on oxygenation and local muscle oxygen consumption (mVO2) in the muscles of the shank during multi-joint whole-body exercise, such as cycling. Although the ankle joints relative contribution to external work production has been shown to be unaffected by changes in cadence [4, 5, 7, 8] the role of power transfer to the cranks [2] can potentially, and as indicated through EMG [12, 13], lead to a change in metabolic requirements of the shank muscles at changing pedalling frequency. Furthermore, the need for stabilization of the limbs at high cadence, as proposed by Boone et al. [17], may increase the metabolic requirements of the shank muscles. Therefore, the purpose of this study was to investigate the effect of cadence on deoxygenation and mVO2 in the lateral gastrocnemius (GAS) and the tibialis anterior (TA) and to investigate the relationship between GAS and TA mVO2 and the joint specific power and cycling kinematics in the ankle. We hypothesised that increasing cadence would lead to a non-uniform effect on deoxygenation and mVO2 of the GAS and TA due to their involvement in plantar and dorsal flexion respectively. Additionally, we hypothesised that we would not find a relationship between joint specific power in the ankle and mVO2 in th (...truncated)