Caveats and Recommendations to Assess the Validity and Reliability of Cycling Power Meters: A Systematic Scoping Review.

A large number of power meters have become commercially available during the last decades to provide power output (PO) measurement. Some of these power meters were evaluated for validity in the literature. This study aimed to perform a review of the available literature on the validity of cycling power meters. PubMed, SPORTDiscus, and Google Scholar have been explored with PRISMA methodology. A total of 74 studies have been extracted for the reviewing process. Validity is a general quality of the measurement determined by the assessment of different metrological properties: Accuracy, sensitivity, repeatability, reproducibility, and robustness. Accuracy was most often studied from the metrological property (74 studies). Reproducibility was the second most studied (40 studies) property. Finally, repeatability, sensitivity, and robustness were considerably less studied with only 7, 5, and 5 studies, respectively. The SRM power meter is the most used as a gold standard in the studies. Moreover, the number of participants was very different among them, from 0 (when using a calibration rig) to 56 participants. The PO tested was up to 1700 W, whereas the pedalling cadence ranged between 40 and 180 rpm, including submaximal and maximal exercises. Other exercise conditions were tested, such as torque, position, temperature, and vibrations. This review provides some caveats and recommendations when testing the validity of a cycling power meter, including all of the metrological properties (accuracy, sensitivity, repeatability, reproducibility, and robustness) and some exercise conditions (PO range, sprint, pedalling cadence, torque, position, participant, temperature, vibration, and field test).

Physiological and biomechanical responses between seated and standing positions during distance­based uphill time trials in elite cyclists.

Cyclists regularly change from a seated to a standing position when the gradient increases during uphill cycling. The aim of this study was to analyse the physiological and biomechanical responses between seated and standing positions during distance-based uphill time trials in elite cyclists. Thirteen elite cyclists completed two testing sessions that included an incremental-specific cycling test on a cycle ergometer to determine VO2max and three distance-based uphill time trials in the field to determine physiological and biomechanical variables. The change from seated to standing position did not influence physiological variables. However, power output was increased by 12.6% in standing position when compared with seated position, whereas speed was similar between the two positions. That involved a significant increase in mechanical cost and tangential force (Ftang) on the pedal (+19% and +22.4%, respectively) and a decrease (-8%) in the pedalling cadence. Additionally, cyclists spent 22.4% of their time in the standing position during the climbing time trials. Our findings showed that cyclists alternated between seated and standing positions in order to maintain a constant speed by adjusting the balance between pedalling cadence and Ftang.

Post-Exercise Hyperbaric Oxygenation Improves Recovery for Subsequent Performance.

Background: The improvement of athletes' recovery seems crucial to maintaining a high-performance level. Since hyperbaric oxygenation (HBO) could be a valuable recovery method, this study aimed at determining the effects of post-exercise HBO at modest pressure (97% O2; 1.3 ATA) on physiological response and subsequent cycling performance compared to passive recovery (PR; 21% O2; 1 ATA). Methods: Twelve trained cyclists completed two testing sessions in a random crossover design. Both sessions consisted of one fatiguing exercise immediately followed by either HBO or PR recovery intervention (75 minutes), then a 5-minute maximal cycling effort. Cycling power output, heart rate variability (HRV) during recovery, blood lactate, and the rating of perceived exertion (RPE) were analyzed and compared between conditions. Results: Compared with PR, the cycling power output was significantly higher after HBO (307.5 ± 19.0 W vs 314.5 ± 19.3 W; p = .005; ES = 0.11 [-0.70-0.90]). Moreover, several HRV indices revealed an improvement in HRV recovery in HBO condition. Blood lactate was not significantly different between conditions, neither following the fatiguing exercise nor the maximal effort. HBO decreased RPE after maximal cycling effort and improved the perceived recovery the day after testing sessions (p < .001). Conclusion: This study suggests that HBO is an efficient strategy to improve cardiac parasympathetic reactivation and is beneficial for subsequent performance.

Influence of standing position on mechanical and energy costs in uphill cycling.

This study was designed to examine the influence of standing position (vs. seated) during uphill cycling on both mechanical cost (MC) and energy cost (EC) in elite cyclists. For the study, thirteen elite cyclists (VO2max: 71.4 ±â€¯8.0 ml·min-1·kg-1) performed, in a randomised order, three sets of exercises. Each set comprised 2 min of exercise, alternating every 30 s between seated and standing postures, using different slopes and intensity levels on a motorised treadmill. MC was calculated from the measurement of power output and speed, whereas EC was calculated from the measurement of oxygen consumption and speed. MC was significantly higher (+4.3%, p < 0.001) in standing position compared to seated position when all slopes and intensities were considered. However, EC was not significantly affected by the change in position. The standing position also induced a significant increase in rolling resistance power (p < 0.001), rolling resistance coefficient (p < 0.001) and lateral sways (p < 0.001). The significant increase in MC observed in standing position was due to a higher rolling resistance induced by bicycle sways and a shift forward of the centre of mass compared to seated position. This result should lead bicycle tire manufacturers to reduce the increase in rolling resistance between the two positions. Considering the relationship observed between the MC and bicycle sways, cyclists would be well advised to decrease the bicycle sways in order to reduce the MC of locomotion.

Dependence of the Nature of the Pedaling Activity on Maximal Aerobic Power in Cycling.

PURPOSE: To analyze the effect of the pedaling activity in different 4-min time trials (TT4s) (laboratory and field conditions) and compare TT4 and maximal aerobic power (MAP) determined from the classical incremental exercise test in laboratory. It was hypothesized that the exercises performed on the field would determine higher physical (power output [PO]) and mental involvements due to different environmental conditions. METHODS: Sixteen male cyclists underwent an incremental test to exhaustion and 3 TT4s under different conditions: cycle ergometer (CE), level ground (LG), and uphill (UP). RESULTS: Correlation was observed for PO with a trivial effect size and narrow limits of agreement between MAP and CE TT4 (r = .96, P < .001). The comparison between the CE, LG, and UP tests indicates that PO was significantly higher in UP than in CE (+8.0%, P < .001) and LG (+11.0%, P < .001). CONCLUSIONS: The results suggest that PO depends on the nature of the pedaling activity. Moreover, PO under CE TT4 is a relevant predictor of MAP. It seems important to measure MAP by taking into account the cycling conditions, considering that coaches and scientists use this parameter to assess the aerobic potential of athletes and determine the exercise intensities useful for monitoring adaptation to training.

Validity, Sensitivity, Reproducibility, and Robustness of the PowerTap, Stages, and Garmin Vector Power Meters in Comparison With the SRM Device.

A large number of power meters have been produced on the market for nearly 20 y according to user requirements. PURPOSE: To determine the validity, sensitivity, reproducibility, and robustness of the PowerTap (PWT), Stages (STG), and Garmin Vector (VCT) power meters in comparison with the SRM device. METHODS: A national-level male competitive cyclist completed 3 laboratory cycling tests: a submaximal incremental test, a submaximal 30-min continuous test, and a sprint test. Two additional tests were performed, the first on vibration exposures in the laboratory and the second in the field. RESULTS: The VCT provided a significantly lower 5-s power output (PO) during the sprint test with a low gear ratio than the SRM did (-36.9%). The STG PO was significantly lower than the SRM PO in the heavy-exercise-intensity zone (zone 2, -5.1%) and the low part of the severe-intensity zone (zone 3, -4.9%). The VCT PO was significantly lower than the SRM PO only in zone 2 (-4.5%). The STG PO was significantly lower in standing position than in the seated position (-4.4%). The reproducibility of the PWT, STG, and VCT was similar to that of the SRM system. The STG and VCT PO were significantly decreased from a vibration frequency of 48 Hz and 52 Hz, respectively. CONCLUSIONS: The PWT, STG, and VCT systems appear to be reproducible, but the validity, sensitivity, and robustness of the STG and VCT systems should be treated with some caution according to the conditions of measurement.

Accuracy of the Suunto system for heart rate variability analysis during a tilt-test / Acurácia do sistema Suunto para a análise da variabilidade da frequência cardíaca durante um teste de inclinação

Abstract The aim of this study was to assess the accuracy of the Suunto Memory Belt (SMB) heart rate (HR) recorder compared with that of a standard electrocardiogram system (ECG) and compared the heart rate variability (HRV) analyses conducted with each dataset. Heart rate was simultaneously recorded using ECG and SMB in fifteen participants [mean (SD) age 27.3 (13.9) years, height 177.4 (10.2) cm and body mass 66.8 (15.3) kg] during an orthostatic tilt test. The two datasets were analysed to compare the number and type of R-R interval artefacts and indices from HRV (RMSSD, pNN50, HF, LF, SD1, and SD2). For artefact detection, 16,742 R-R intervals were analysed during all recordings. Only 18 artefacts, 9 type 1 (long R-R interval) and 9 type 2 (short R-R interval), were identified with the SMB. Bland-Altman analysis indicated excellent accuracy for the SMB, with limits of agreement of -2.00 and +1.94 ms. Further, the reference and SMB systems were strongly correlated. The similarity between each device indicated that the SMB could reliably record R-R intervals.

Resumo Este estudo foi realizado com o objetivo de avaliar a precisão das medidas de Frequencia cardíaca (FC) e da variabilidade da FC (VFC) obtidas através de um cardiofrequencímetro Suunto Memory Belt, em comparação com um sistema de eletrocardiograma (ECG) de referência. Quinze participantes [média (desvio padrão), idade de 27,3 (13,9) anos, estatura de 177,4 (10,2) cm e massa corporal de 66,8 (15,3) kg] foram equipados para o registro simultâneo da FC através do ECG de referência e do cardiofrequencímetro Suunto Memory Belt durante um teste de inclinação ortostático. Os dados obtidos pelos dois sistemas foram analisados para comparar o número e tipo de artefatos dos interavalos R-R e também comparar diversos indices de VFC (RMSSD, pNN50, HF, LF, SD1 e SD2). Para todos os participantes, foram analisados 16.742 intervalos R-R e comparados entre os dois sistemas. Somente 18 artefatos foram encontrados para o Suunto Memory Belt em relação o ECG de referência: 9 foram do tipo 1 (intervalos RR longos) e 9 do tipo 2 (intervalos RR curtos). A análise de Bland-Altman mostrou excelente precisão do sistema Suunto Memory Belt com limites de concordância entre -2.00 e +1.94 ms. O sistema Suunto Memory Belt também mostrou uma forte correlação com o sistema ECG de referência. De acordo com os testes realizados, e a similaridade com o ECG de refêrencia conclui-se que o Suunto Memory Belt é capaz de registrar de forma precisa os intervalos R-R.