| 1. |
- Cassirame, Johan, et al.
(författare)
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Heart rate variability to assess ventilatory threshold in ski-mountaineering
- 2015
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Ingår i: European Journal of Sport Science. - : Informa UK Limited. - 1746-1391 .- 1536-7290. ; 15:7, s. 615-622
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Tidskriftsartikel (refereegranskat)abstract
- The capacity to predict the heart rate (HR) and speed at the first (VT1) and second (VT2) ventilatory thresholds was evaluated during an incremental ski-mountaineering test using heart rate variability (HRV). Nine skiers performed a field test to exhaustion on an alpine skiing track. VT1 and VT2 were individually determined by visual analysis from gas exchanges (VT1V and VT2V) and time-varying spectral HRV analysis (VT1fH, VT2fH and VT2H). VT1 could not be determined with the HRV methods used. On the contrary, the VT2 was determined in all skiers. No significant difference between HR and speed at VT2H and VT2V was observed (174.3 +/- 5.6 vs. 174.3 +/- 5.3 bpm, and 6.3 +/- 0.9 and 6.3 +/- 0.9 km h(-1), respectively). Strong correlations were obtained for HR (r = 0.91) and speed (r = 0.92) at VT2H and VT2V with small limits of agreement (+/- 3.6 bpm for HR). Our results indicated that HRV enables determination of HR and speed at VT2 during a specific ski-mountaineering incremental test. These findings provide practical applications for skiers in order to evaluate and control specific training loads, at least when referring to VT2.
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| 2. |
- Fabré, Nicolas, et al.
(författare)
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Alterations in aerobic energy expenditure and neuromuscular function during a simulated cross-country skiathlon with the skating technique
- 2015
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Ingår i: Human Movement Science. - : Elsevier BV. - 0167-9457 .- 1872-7646. ; 40, s. 326-340
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Tidskriftsartikel (refereegranskat)abstract
- Here, we tested the hypothesis that aerobic energy expenditure (AEE) is higher during a simulated 6-km (2 loops of 3-km each) "skiathlon" than during skating only on a treadmill and attempted to link any such increase to biomechanical and neuromuscular responses. Six elite male cross-country skiers performed two pretesting time-trials (TT) to determine their best performances and to choose an appropriate submaximal speed for collection of physiological, biomechanical and neuromuscular data during two experimental sessions ((exp)). Each skier used, in randomized order, either the classical (CL) or skating technique (SK) for the first 3-km loop, followed by transition to the skating technique for the second 3-km loop. Respiratory parameters were recorded continuously. The EMG activity of the triceps brachii (TBr and vastus lateralis (VLa) muscles during isometric contractions performed when the skiers were stationary (i.e., just before the first loop, during the transition, and after the second loop); their corresponding activity during dynamic contractions; and pole and plantar forces during the second loop were recorded. During the second 3-km of the 'IT, skating speed was significantly higher for the SK-SK than CL-SK. During this second loop, AEE was also higher (+1.5%) for CL-SKexp than SK-SKexp, in association with higher VLa EMG activity during both isometric and dynamic contractions, despite no differences in plantar or pole forces, poling times or cycle rates. Although the underlying mechanism remains unclear, during a skiathlon, the transition between the sections of classical skiing and skating alters skating performance (i.e., skiing speed), AEE and neuromuscular function. (C) 2015 Elsevier B.V. All rights reserved.
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| 3. |
- Gallina, Barbara, et al.
(författare)
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Benefits of Security-informed Safety-oriented Process Line Engineering
- 2015
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Ingår i: Digital Avionics Systems Conference DASC-34. - Prague, Czech Republic : IEEE. - 9781479989409
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Konferensbidrag (refereegranskat)abstract
- Nowadays, given the growing aircraft connectivity, security-informed safety is crucial. To certify aircrafts, safety as well as security standards need to be taken into consideration. In this context, a process engineer has to succeed in mastering the growing complexity of the standards interplay. To support process engineers, we propose to: first, consider a common terminological framework, aimed at reconciling security and safety within dependability; then identify and systematize commonalities and variabilities between the processes. To enable this systematization we introduce Security-informed Safety-oriented Process Line Engineering (SiSoPLE), which extends SoPLE to address security concerns. To show the effectiveness and benefits of SiSoPLE, we apply this new process line engineering to two aerospace standards, SAE ARP 4761 (Safety) and RTCA DO-326A (Security). We then provide our lessons learned and concluding remarks. Finally, we sketch some perspectives for future investigation.
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| 4. |
- Hohenschurz-Schmidt, David, et al.
(författare)
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Recommendations for the development, implementation, and reporting of control interventions in efficacy and mechanistic trials of physical, psychological, and self-management therapies : the CoPPS Statement
- 2023
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Ingår i: BMJ. British Medical Journal. - : BMJ Publishing Group Ltd. - 0959-8146 .- 0959-535X. ; 381, s. e072108-
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Tidskriftsartikel (refereegranskat)abstract
- Control interventions (often called "sham," "placebo," or "attention controls") are essential for studying the efficacy or mechanism of physical, psychological, and self-management interventions in clinical trials. This article presents core recommendations for designing, conducting, and reporting control interventions to establish a quality standard in non-pharmacological intervention research. A framework of additional considerations supports researchers' decision making in this context. We also provide a reporting checklist for control interventions to enhance research transparency, usefulness, and rigour.
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| 5. |
- Mourot, Laurent, et al.
(författare)
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Cross-Country Skiing and Postexercise Heart-Rate Recovery
- 2015
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Ingår i: International Journal of Sports Physiology and Performance. - : Human Kinetics. - 1555-0265 .- 1555-0273. ; 10:1, s. 11-16
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Tidskriftsartikel (refereegranskat)abstract
- Postexercise heart-rate (HR) recovery (HRR) indices have been associated with running and cycling endurance-exercise performance. The current study was designed (1) to test whether such a relationship also exists in the case of cross-country skiing (XCS) and (2) to determine whether the magnitude of any such relationship is related to the intensity of exercise before obtaining HRR indices. Ten elite male cross-country skiers (mean +/- SD; 28.2 +/- 5.4 y, 181 +/- 8 cm, 77.9 +/- 9.4 kg, 69.5 +/- 4.3 mL.min(-1) . kg(-1) maximal oxygen uptake [VO2max]) performed 2 sessions of roller-skiing on a treadmill: a 2 x 3-km time trial and the same 6-km at an imposed submaximal speed followed by a final 800-m time trial. VO2 and HR were monitored continuously, while HRR and blood lactate (BLa) were assessed during 2 min immediately after each 6-km and the 800-m time trial. The 6-km time-trial time was largely negatively correlated with VO2max and BLa. On the contrary, there was no clear correlation between the 800-m time-trial time and VO2, HR, or BLa. In addition, in no case was any clear correlation between any of the HRR indices and performance time or VO2max observed. These findings confirm that XCS performance is largely correlated with VO2max and the ability to tolerate high levels of BLa; however, postexercise HRR showed no clear association with performance. The homogeneity of the group of athletes involved and the contribution of the arms and upper body to the exercise preceding determination of HRR may explain this absence of a relationship.
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| 6. |
- Mourot, Laurent, et al.
(författare)
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Second Ventilatory Threshold From Heart-Rate Variability : Valid When the Upper Body Is Involved?
- 2014
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Ingår i: International Journal of Sports Physiology and Performance. - 1555-0265 .- 1555-0273. ; 9:4, s. 695-701
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Tidskriftsartikel (refereegranskat)abstract
- To determine the most accurate method based on spectral analysis of heart-rate variability (SA-HRV) during an incremental and continuous maximal test involving the upper body, the authors tested 4 different methods to obtain the heart rate (HR) at the second ventilatory threshold (VT2). Sixteen ski mountaineers (mean +/- SD; age 25 +/- 3 y, height 177 +/- 8 cm, mass 69 +/- 10 kg) performed a roller-ski test on a treadmill. Respiratory variables and HR were continuously recorded, and the 4 SA-HRV methods were compared with the gas-exchange method through Bland and Altman analyses. The best method was the one based on a time-varying spectral analysis with high frequency ranging from 0.15 Hz to a cutoff point relative to the individual's respiratory sinus arrhythmia. The HR values were significantly correlated (r(2) = .903), with a mean HR difference with the respiratory method of 0.1 +/- 3.0 beats/min and low limits of agreements (around -6 /+ 6 beats/min). The 3 other methods led to larger errors and lower agreements (up to 5 beats/min and around -23/+ 20 beats/min). It is possible to accurately determine VT2 with an HR monitor during an incremental test involving the upper body if the appropriate HRV method is used.
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