Evidence map›Paper›PMID 28785797›Full record

ArticleEuropean journal of applied physiology2017

Changing relative crank angle increases the metabolic cost of leg cycling.

Asher H Straw, Wouter Hoogkamer, Rodger Kram

Abstract read
PubMed Publisher
In one paragraph

Article in European journal of applied physiology, 2017. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

0numbers the graph read from it
0cells of the map it votes in
0citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

0 citing papers in PubMed.

No citing paper in PubMed yet.

4 · The record

Corrections and comments

PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.

5 · Who and what money

Authors and funding

3 authors.

Asher H StrawDepartment of Integrative Physiology, Locomotion Lab, University of Colorado, Boulder, CO, 80309-0354, USA. asher.straw@colorado.edu.
Wouter HoogkamerDepartment of Integrative Physiology, Locomotion Lab, University of Colorado, Boulder, CO, 80309-0354, USA.
Rodger KramDepartment of Integrative Physiology, Locomotion Lab, University of Colorado, Boulder, CO, 80309-0354, USA.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

purposeHistorically, the efficiency of leg cycling has been difficult to change. However, arm cycling research indicates that relative crank angle changes can improve efficiency. Therefore, we investigated if leg cycling with different relative crank angles affects efficiency.

methodsTen healthy, male, recreational bicycle riders (27.8 ± 8.2 years, mean ± SD, mass 69.8 ± 3.2 kg) pedaled a pan-loaded cycle ergometer at a fixed power output of 150 watts at a cadence of 90 RPM. Each subject completed six, 5-min trials in random order at relative crank angles of 180°, 135°, 90°, 45°, 0°, and 180°. We averaged rates of oxygen uptake ([Formula: see text]) and carbon dioxide production ([Formula: see text]), and respiratory exchange ratio (RER) for the last 2 min of each trial.

resultsCrank angles other than 180° required a greater metabolic cost. As relative crank angle decreased from 180°, metabolic power monotonically increased by 1.6% at 135° to 8.2% greater when the relative crank angle was 0° (p < 0.001).

conclusionsWe find that, unlike arm cycling, radically changing the relative crank angle on a bicycle from an out-of-phase (180°) to in-phase (0°) position decreases leg cycling efficiency by ~8%. We attribute the increase to changes in cost of breathing, muscle co-activation, trunk stabilization, power fluctuations, and possibly lifting the legs during the upstroke. Our findings may have relevance in the rehabilitation of patients recovering from stroke or spinal cord injury.

Indexed as

Energy MetabolismOxygen ConsumptionAdultBicyclingBiomechanical PhenomenaHumansLegMaleMuscle, SkeletalPulmonary Gas ExchangePulmonary VentilationRandom AllocationAsynchronousBicycleEfficiencySynchronousVentilation

Identifiers

What OpenQuestion holds

Textmetadata
Read underepoch 390

Registered trials

None linked

Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.