Dataset Information

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

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.

SUBMITTER: Skovereng K

PROVIDER: S-EPMC5217861 | biostudies-literature | 2017

REPOSITORIES: biostudies-literature

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

Skovereng Knut K Ettema Gertjan G van Beekvelt Mireille M

PloS one 20170106 1

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 rp ...[more]

PMID: 28060894

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Project description:IntroductionIn cycling, the utilization of the drops position (i.e. the lowest handlebar position relative to the ground) allows for reduced frontal area, likely improved aerodynamics and thus performance compared to the tops (i.e. the position producing the most upright trunk). The reduced trunk angle during seated submaximal cycling has been shown to influence cardiorespiratory factors but the effects on pedalling forces and joint specific power are unclear. The purpose of this study was to investigate the effect of changing handgrip position on joint specific power and cycling kinematics at different external work rates in recreational and professional cyclists.MethodNine professional and nine recreational cyclists performed cycling bouts using three different handgrip positions and three external work rates (i.e. 100W, 200W and external work rate corresponding to the lactate threshold (WRlt)). Joint specific power was calculated from kinematic measurements and pedal forces using 2D inverse dynamics.ResultsWe found increased hip joint power, decreased knee joint power and increased peak crank torque for the professional cyclist compared to the recreational cyclists, but only at WRlt where the professional cyclists were working at a higher external work rate. There was no main effect of changing handgrip position on any joint, but there was a small interaction effect of external work rate and handgrip position on hip joint power contribution (Generalized eta squared (ηg2) = 0.012). At 100W, changing handgrip position from the tops to the drops decreased the hip joint contribution (-2.0 ± 3.9 percentage points (pct)) and at the WRlt, changing handgrip position increased the hip joint power (1.6 ± 3.1 pct). There was a small effect of handgrip position with the drops leading to increased peak crank torque (ηg2 = 0.02), increased mean dorsiflexion (ηg2 = 0.05) and increased hip flexion (ηg2 = 0.31) compared to the tops.DiscussionThe present study demonstrates that there is no main effect of changing handgrip position on joint power. Although there seems to be a small effect on hip joint power when comparing across large ranges in external work rate, any potential negative performance effect would be outweighed by the aerodynamic benefit of the drops position.

Project description:The majority of morbidity and mortality in sickle cell disease is caused by vaso-occlusion: circulatory obstruction leading to tissue ischemia and infarction. The consequences of vaso-occlusion are seen clinically throughout the vascular tree, from the relatively high-oxygen and high-velocity cerebral arteries to the relatively low-oxygen and low-velocity postcapillary venules. Prevailing models of vaso-occlusion propose mechanisms that are relevant only to regions of low oxygen and low velocity, leaving a wide gap in our understanding of the most important pathologic process in sickle cell disease. Progress toward understanding vaso-occlusion is further challenged by the complexity of the multiple processes thought to be involved, including, but not limited to 1) deoxygenation-dependent hemoglobin polymerization leading to impaired rheology, 2) endothelial and leukocyte activation, and 3) altered cellular adhesion. Here, we chose to focus exclusively on deoxygenation-dependent rheologic processes in an effort to quantify their contribution independent of the other processes that are likely involved in vivo. We take advantage of an experimental system that, to our knowledge, uniquely enables the study of pressure-driven blood flow in physiologic-sized tubes at physiologic hematocrit under controlled oxygenation conditions, while excluding the effects of endothelium, leukocyte activation, adhesion, inflammation, and coagulation. We find that deoxygenation-dependent rheologic processes are sufficient to increase apparent viscosity significantly, slowing blood flow velocity at arterial oxygen tension even without additional contributions from inflammation, adhesion, and endothelial and leukocyte activation. We quantify the changes in apparent viscosity and define a set of functional regimes of sickle cell blood flow personalized for each patient that may be important in further dissecting mechanisms of in vivo vaso-occlusion as well as in assessing risk of patient complications, response to transfusion, and the optimization of experimental therapies in development.

Project description:BackgroundEfficacy of exercise to improve motor symptoms in Parkinson's Disease (PD) has been established in multiple clinical trials. The Pedaling for Parkinson's ™ (PFP) program is an existing community-based cycling intervention for individuals with PD. Although PFP program design was informed by in-laboratory efficacy studies, the implementation and effectiveness of the program in the community have not been studied. This feasibility study explores implementation and effectiveness of PFP utilizing the RE-AIM implementation evaluation framework.MethodsThis was a pragmatic open-label multi-site study. First, community-based gyms were recruited to implement the PFP protocol with enhanced multi-modal training and support. Second individuals with Hoehn and Yahr stage I-III idiopathic PD were recruited to participate. Reach, effectiveness (both clinical scores and participant enjoyment), adoption, implementation (gym and participant fidelity, cost), and maintenance (sustainability) were assessed. Tracking of adverse events was used to monitor safety of the intervention.ResultsReach was moderate: 59% of participants who expressed interest opted to participate. No effectiveness outcomes demonstrated a significant change from pre to post; however, the program was highly enjoyable (96% of participants who started classes enjoyed the program and 87% wished to continue). Adoption was poor with only four out of 34 gyms participating. The program had poor gym and moderate participant fidelity. The program was maintained for at least 4 months across all sites. The program was implemented safely.ConclusionBarriers to implementation of nonpharmacologic interventions such as exercise protocols limit reach and availability of these interventions to patients. Pilot studies are needed to inform and direct further implementation efforts. Our pilot study suggests the PFP cycling intervention should be modified prior to attempts at widespread implementation. Modifications made by gyms in this study suggest adaptations to the protocol that may increase fidelity and effectiveness.

Dataset Information

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

Publications

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

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