| 1. |
- Nilsson, Johnny E, et al.
(författare)
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New Devices for Measuring Forces on the Kayak Foot-Bar and on the Seat During Flat-Water Kayak Paddling : a technical report.
- 2014
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Ingår i: International Journal of Sports Physiology and Performance. - : Human Kinetics. - 1555-0265 .- 1555-0273. ; 9:2, s. 365-70
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Tidskriftsartikel (refereegranskat)abstract
- The purpose was to develop and validate portable force-measurement devices for recordings of push and pull forces applied by each foot to the foot-bar of a kayak, and the horizontal force at the seat. A foot-plate on a single-point force transducer mounted on the kayak foot-bar underneath each foot allowed the push and pull forces to be recorded. Two metal frames interconnected with four linear ball-bearings and a force transducer allowed recording of horizontal seat force. The foot-bar force device was calibrated by loading each foot plate with weights in the push pull direction perpendicular to the foot plate surface while the seat force device was calibrated to horizontal forces with and without weights on the seat. A strong linearity (r2=0.99-1.0) was found between transducer output signal and load force in the push and pull directions for both foot-bar transducers perpendicular to the foot plate and the seat-force measuring device. Reliability of both devices was tested by means of a test-retest design. The coefficient of variation (CV) for foot-bar push and pull forces ranged from 0.1 to 1.1% and the CV for the seat forces varied between 0.6 - 2.2%. The present study opens up for new investigations of the forces generated within the kayak and ways to optimize kayak paddling performance.
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| 2. |
- Rosdahl, Hans, et al.
(författare)
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Evaluation of the Oxycon Mobile metabolic system against the Douglas bag method
- 2010
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 109:2, s. 159-171
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate two versions of the Oxycon Mobile portable metabolic system, (OMPS1 and OMPS2) in a wide range of oxygen uptake, using the Douglas bag method (DBM) as criterion method. The metabolic variables VO2, VCO2, respiratory exchange ratio and VE were measured during submaximal and maximal cycle ergometer exercise with sedentary, moderately trained individuals and athletes as participants. Test-retest reliability was investigated using the OMPS1. The coefficients of variation varied between 2% and 7% for the metabolic parameters measured at different work rates, and resembled those obtained with the DBM. With the OMPS1, systematic errors were found in the determination of VO2 and VCO2. At submaximal work rates VO2 was 6-14% and VCO2 5-9% higher than with the DBM. At VO2max both VO2 and VCO2 were slightly lower as compared to DBM (-4.1% and -2.8% respectively). With OMPS2, VO2 was determined accurately within a wide measurement range (about 1-5.5 L*min-1), while VCO2 was overestimated (3-7%). VE was accurate at submaximal work rates with both OMPS1 and OMPS2, whereas underestimations (4-8%) were noted at VO2max. The present study is the first to demonstrate that a wide range of VO2 can be measured accurately with the Oxycon Mobile portable metabolic system (second generation). Future investigations are suggested to clarify reasons for the small errors noted for VE and VCO2 versus the Douglas bag measurements, and also to gain knowledge of the performance of the device under applied and non-laboratory conditions.
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| 3. |
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| 4. |
- Rosdahl, Hans, et al.
(författare)
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The Moxus Modular metabolic sustem evaluated with two sensors for ventilation against the Douglas bag method
- 2013
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Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 113:5, s. 1353-1367
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Tidskriftsartikel (refereegranskat)abstract
- This study evaluated the Moxus metabolic system with the Douglas bag method (DBM) as criterion. Reliability and validity were investigated in a wide range of ventilation and oxygen uptake and two sensors for determining ventilation were included. Thirteen well-trained athletes participated in one pre-test and four tests for data collection, exercising on a cycle ergometer at five submaximal powers (50-263 W) and at [Formula: see text]. Gas exchange variables were measured simultaneously using a serial setup with data collected on different days in an order randomized between Moxus with pneumotachometer (MP) and turbine flowmeter (MT) sensors for ventilation. Reliability with both sensors was comparable to the DBM. Average CV (%) of all exercise intensities were with MP: 3.0 ± 1.3 for VO(2), 3.8 ± 1.5 for VCO(2), 3.1 ± 1.2 for the respiratory exchange ratio (RER) and 4.2 ± 0.8 for V (E). The corresponding values with MT were: 2.7 ± 0.3 for VO(2), 4.7 ± 0.4 for VCO(2), 3.3 ± 0.9 for RER and 4.8 ± 1.4 for V (E). Validity was acceptable except for small differences related to the determination of ventilation. The relative differences in relation to DBM at the powers including [Formula: see text] were similar for both sensors with the ranges being: +4 to -2 % for V (E), +5 to -3 % for VO(2) and +5 to -4 % for VCO(2) while RER did not differ at any power. The Moxus metabolic system shows high and adequate reliability and reasonable validity over a wide measurement range. At a few exercise levels, V (E) differed slightly from DBM, resulting in concomitant changes in VO(2) and VCO(2).
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| 5. |
- Salier Eriksson, Jane, et al.
(författare)
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Validity of the Oxycon Mobile metabolic system under field measuring conditions
- 2012
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Ingår i: European Journal of Applied Physiology. - : Springer. - 1439-6319 .- 1439-6327. ; 112:1, s. 345-355
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Tidskriftsartikel (refereegranskat)abstract
- Abstract Purpose: It is essential to validate portable metabolic systems, not only in laboratory settings, but also in field measuring conditions, such as prolonged moderate exercise at low temperatures, high humidity and with external wind. Methods: VO2, VCO2, RER and VE were measured using the Oxycon Mobile (OM), with a windshield, during cycle ergometer exercise: (I) indoors at three submaximal workloads with no wind or with external wind (13–20 m·s-1) from front, side and back; (II) at two submaximal workloads outdoors (12 ± 2oC; 86 ± 7% RH), with and without a system for drying the ambient air around the air sampling tube; and (III) at one workload outdoors for 45 min (5 ± 4oC; 69 ± 16.5% RH). Any physiological drift was checked for with pre- and postmeasurements by the Douglas bag method (DBM). Results: A minor effect of external wind from behind was noted in RER and VE (-2 and -3%).. The system for drying the ambient air around the gas sampling tube had no effect on the measured levels. A small difference in VCO2 drift between the OM and DBM (1.5 mL·min-2) was noted in the stability test. Conclusion: Heavy external wind applied from different directions generally does not affect the measurements of the OM. Furthermore, when using a unit for drying the ambient air around the gas sampling tube, the OM can accurately measure VO2, RER and VE at submaximal workloads for at least45 min under challenging conditions with regard to humidity and temperature.
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