A New Procedure to Determine External Power Output During Handrim Wheelchair Propulsion on a Roller Ergometer: A Reliability Study

A novel approach has been developed for the quantification of total mechanical power output produced by an isolated, well-defined muscle group during dynamic exercise in humans at different contraction frequencies. The calculation of total power output comprises the external power delivered to the ergometer (i.e., the external power output setting of the ergometer) and the “internal” power generated to overcome inertial and gravitational forces related to movement of the lower limb. Total power output was determined at contraction frequencies of 60 and 100 rpm. At 60 rpm, the internal power was 18 ± 1 W (range: 16–19 W) at external power outputs that ranged between 0 and 50 W. This was less ( P < 0.05) than the internal power of 33 ± 2 W (27–38 W) at 100 rpm at 0–50 W. Moreover, at 100 rpm, internal power was lower ( P < 0.05) at the higher external power outputs. Pulmonary oxygen uptake was observed to be greater ( P< 0.05) at 100 than at 60 rpm at comparable total power outputs, suggesting that mechanical efficiency is lower at 100 rpm. Thus a method was developed that allowed accurate determination of the total power output during exercise generated by an isolated muscle group at different contraction frequencies.

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Biomechanical analysis to determine the external power output on an immersible ergocycle

European Journal of Sport Science ◽

10.1080/17461391.2014.932015 ◽

2014 ◽

Vol 15 (4) ◽

pp. 271-278 ◽

Cited By ~ 12

Author(s):

Mauricio Garzon ◽

Mathieu Gayda ◽

Leonardo Garzon ◽

Martin Juneau ◽

Anil Nigam ◽

...

Keyword(s):

Power Output ◽

Biomechanical Analysis ◽

External Power

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The Relationship Between Freely Chosen Cadence and Optimal Cadence in Cycling

International Journal of Sports Physiology and Performance ◽

10.1123/ijspp.7.4.375 ◽

2012 ◽

Vol 7 (4) ◽

pp. 375-381 ◽

Cited By ~ 4

Author(s):

Umberto Emanuele ◽

Tamara Horn ◽

Jachen Denoth

Keyword(s):

Power Output ◽

Body Position ◽

Lactate Concentration ◽

Blood Lactate Concentration ◽

Peripheral Fatigue ◽

External Power ◽

The Relationship ◽

Optimal Cadence ◽

Cycling Condition ◽

Constant Power Output

Purpose:The main aim of this study was to compare the freely chosen cadence (FCC) and the cadence at which the blood lactate concentration at constant power output is minimized (optimal cadence [Copt]). The second aim was to examine the effect of a concomitant change of road incline and body position on FCC, the maximal external power output (Pmax), and the corresponding Copt.Methods:FCC, Copt, and Pmax were analyzed under 2 conditions: cycling on level ground in a dropped position (LGDP) and cycling uphill in an upright position (UHUP). Seven experienced cyclists participated in this study. They cycled on a treadmill to test the 2 main hypotheses: Experienced cyclists would choose an adequate cadence close to Copt independent of the cycling condition, and FCC and Copt would be lower and Pmax higher for UHUP than with LGDP.Results:Most but not all experienced cyclists chose an adequate cadence close to Copt. Independent of the cycling condition, FCC and Copt were not statistically different. FCC (82.1 ± 11.1 and 89.3 ± 10.6 rpm, respectively) and Copt (81.5 ± 9.8 and 87.7 ± 10.9 rpm, respectively) were significantly lower and Pmax was significantly higher (2.0 ± 2.1%) for UHUP than for LGDP.Conclusion:Most experienced cyclists choose a cadence near Copt to minimize peripheral fatigue at a given power output independent of the cycling condition. Furthermore, it is advantageous to use a lower cadence and a more upright body position during uphill cycling.

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VIBRATION ENERGY HARVESTING TECHNIQUE: A COMPREHENSIVE REVIEW

Engineering Heritage Journal ◽

10.26480/gwk.02.2020.46.48 ◽

2020 ◽

Vol 4 (2) ◽

pp. 46-48

Author(s):

Nik Fakhri Nek Daud ◽

Ruzlaini Ghoni

Keyword(s):

Energy Harvesting ◽

Power Output ◽

Energy Conversion Efficiency ◽

Vibration Energy Harvesting ◽

Energy Harvesters ◽

Output Performance ◽

Harvesting Technique ◽

External Power Source ◽

External Power ◽

Future Requirement

In order to minimize the requirement of external power source and maintenance for electric devices such as wireless sensor networks, the energy harvesting technique based on vibrations has been a dynamic field of studying interest over past years. Researchers have concentrated on developing efficient energy harvesters by adopting new materials and optimizing the harvesting devices. One important limitation of existing energy harvesting techniques is that the power output performance is seriously subject to the resonant frequencies of ambient vibrations, which are often random and broadband. This paper reviews important vibration-to-electricity conversion mechanisms, including theory, modelling methods and the realizations of the piezoelectric, electromagnetic and electrostatic approaches. Different types of energy harvesters that have been designed with nonlinear characteristics are also reviewed. As one of important factors to estimate the power output performance, the energy conversion efficiency of different conversion mechanisms is also summarized. Finally, the challenging issues based on the existing methods and future requirement of energy harvesting are also discussed.

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Physiological and biomechanical comparison of overground, treadmill, and ergometer handrim wheelchair propulsion in able-bodied subjects under standardized conditions

Journal of NeuroEngineering and Rehabilitation ◽

10.1186/s12984-020-00767-2 ◽

2020 ◽

Vol 17 (1) ◽

Author(s):

Rick de Klerk ◽

Vera Velhorst ◽

Dirkjan (H.E.J.) Veeger ◽

Lucas H. V. van der Woude ◽

Riemer J. K. Vegter

Keyword(s):

Power Output ◽

Ecological Validity ◽

Statistical Parametric Mapping ◽

Physiological Data ◽

Total Force ◽

Wheelchair Propulsion ◽

Continuous Analysis ◽

Measurement Session ◽

Lower Torque ◽

Biomechanical Comparison

Abstract Background Handrim wheelchair propulsion is often assessed in the laboratory on treadmills (TM) or ergometers (WE), under the assumption that they relate to regular overground (OG) propulsion. However, little is known about the agreement of data obtained from TM, WE, and OG propulsion under standardized conditions. The current study aimed to standardize velocity and power output among these three modalities to consequently compare obtained physiological and biomechanical outcome parameters. Methods Seventeen able-bodied participants performed two submaximal practice sessions before taking part in a measurement session consisting of 3 × 4 min of submaximal wheelchair propulsion in each of the different modalities. Power output and speed for TM and WE propulsion were matched with OG propulsion, making them (mechanically) as equal as possible. Physiological data and propulsion kinetics were recorded with a spirometer and a 3D measurement wheel, respectively. Results Agreement among conditions was moderate to good for most outcome variables. However, heart rate was significantly higher in OG propulsion than in the TM condition. Push time and contact angle were smaller and fraction of effective force was higher on the WE when compared to OG/TM propulsion. Participants used a larger cycle time and more negative work per cycle in the OG condition. A continuous analysis using statistical parametric mapping showed a lower torque profile in the start of the push phase for TM propulsion versus OG/WE propulsion. Total force was higher during the start of the push phase for the OG conditions when compared to TM/WE propulsion. Conclusions Physiological and biomechanical outcomes in general are similar, but possible differences between modalities exist, even after controlling for power output using conventional techniques. Further efforts towards increasing the ecological validity of lab-based equipment is advised and the possible impact of these differences -if at all- in (clinical) practice should be evaluated.

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Force Application During Handcycling and Handrim Wheelchair Propulsion: An Initial Comparison

Journal of Applied Biomechanics ◽

10.1123/jab.29.6.687 ◽

2013 ◽

Vol 29 (6) ◽

pp. 687-695 ◽

Cited By ~ 18

Author(s):

Ursina Arnet ◽

Stefan van Drongelen ◽

DirkJan Veeger ◽

Lucas H. V. van der Woude

Keyword(s):

Power Output ◽

Three Dimensional ◽

Wheelchair Propulsion ◽

Force Application ◽

Initial Comparison ◽

Applied Forces

The aim of the study was to evaluate the external applied forces, the effectiveness of force application and the net shoulder moments of handcycling in comparison with handrim wheelchair propulsion at different inclines. Ten able-bodied men performed standardized exercises on a treadmill at inclines of 1%, 2.5% and 4% with an instrumented handbike and wheelchair that measured three-dimensional propulsion forces. The results showed that during handcycling significantly lower mean forces were applied at inclines of 2.5% (P< .001) and 4% (P< .001) and significantly lower peak forces were applied at all inclines (1%:P= .014, 2.5% and 4%:P< .001). At the 2.5% incline, where power output was the same for both devices, total forces (mean over trial) of 22.8 N and 27.5 N and peak forces of 40.1 N and 106.9 N were measured for handbike and wheelchair propulsion. The force effectiveness did not differ between the devices (P= .757); however, the effectiveness did increase with higher inclines during handcycling whereas it stayed constant over all inclines for wheelchair propulsion. The resulting peak net shoulder moments were lower for handcycling compared with wheelchair propulsion at all inclines (P< .001). These results confirm the assumption that handcycling is physically less straining.

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