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- Fabré, Nicolas, et al.
(författare)
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A novel approach for lactate threshold assessment based on rating of perceived exertion
- 2013
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Ingår i: International Journal of Sports Physiology and Performance. - 1555-0265 .- 1555-0273. ; 8:3, s. 263-270
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Tidskriftsartikel (refereegranskat)abstract
- This study tested the hypothesis that the DMAX (for maximal distance) method could be applied to ratings of perceived exertion (RPE), to propose a novel method for individual detection of the lactate threshold (LT) using RPE alone during an incremental test to exhaustion. Twenty-one participants performed an incremental test on a cycle ergometer. At the end of each stage, lactate concentration was measured and the participants estimated RPE using the Borg CR100 scale. The intensity corresponding to the fixed lactate values of 2 or 4 mmol • L-1 (2mM and 4mM), the ventilatory threshold (VT), the respiratory-compensation point (RCP), and the instant of equality of pulmonary gas exchange (RER=1.00) were determined. Lactate (DMAX La) and RPE (DMAX RPE) thresholds were determined using the DMAX method. Oxygen uptake (VO2), heart rate, and power output measured at DMAX RPE and at D MAX La were not statistically different. Bland-Altman plots showed small bias and good agreements when DMAX RPE was compared with the DMAX La and RER=1.00 methods (bias = -0.05% and -2% of VO2max, respectively). Conversely, VO2 from the D MAX RPE method was lower than VO2 at 4 mM and at RCP and was higher than VO2 at 2 mM and at VT. VO2 at D MAX RPE was strongly correlated with VO2 at D MAX La (r = .97), at RER=1.00 (r = .97), at 2 mM (r = .85), at 4 mM (r = .93), at VT (r = .95), and at RCP (r = .95). The combination of the DMAX method with the RPE responses permitted precise and individualized estimates of LT using the DMAX method.
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| 2. |
- Lussiana, T., et al.
(författare)
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Effect of slope and footwear on running economy and kinematics
- 2013
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Ingår i: Scandinavian Journal of Medicine and Science in Sports. - : Wiley. - 0905-7188 .- 1600-0838. ; 23:4, s. e246-e253
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Tidskriftsartikel (refereegranskat)abstract
- Lower energy cost of running (Cr) has been reported when wearing minimal (MS) vs traditional shoes (TS) on level terrain, but the effect of slope on this difference is unknown. The aim of this study was to compare Cr, physiological, and kinematic variables from running in MS and TS on different slope conditions. Fourteen men (23.4 +/- 4.4 years; 177.5 +/- 5.2cm; 69.5 +/- 5.3kg) ran 14 5-min trials in a randomized sequence at 10km/h on a treadmill. Subjects ran once wearing MS and once wearing TS on seven slopes, from -8% to +8%. We found that Cr increased with slope gradient (P<0.01) and was on average 1.3% lower in MS than TS (P<0.01). However, slope did not influence the Cr difference between MS and TS. In MS, contact times were lower (P<0.01), flight times (P=0.01) and step frequencies (P=0.02) were greater at most slope gradients, and plantar-foot angles - and often ankle plantar-flexion (P=0.01) - were greater (P<0.01). The 1.3% difference between footwear identified here most likely stemmed from the difference in shoe mass considering that the Cr difference was independent of slope gradient and that the between-footwear kinematic alterations with slope provided limited explanations.
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