Torque-Cadence Profile and Maximal Dynamic Force in Cyclists: A Novel Approach.

We aimed to determine the feasibility, test-retest reliability and long-term stability of a novel method for assessing the force (torque)-velocity (cadence) profile and maximal dynamic force (MDF) during leg-pedaling using a friction-loaded isoinertial cycle ergometer and a high-precision power-meter device. Fifty-two trained male cyclists completed a progressive loading test up to the one-repetition maximum (1RM) on a cycle ergometer. The MDF was defined as the force attained at the cycle performed with the 1RM-load. To examine the test-retest reliability and long-term stability of torque-cadence values, the progressive test was repeated after 72 h and also after 10 weeks of aerobic and strength training. The participants' MDF averaged 13.4 ± 1.3 N·kg-1, which was attained with an average pedal cadence of 21 ± 3 rpm. Participants' highest power output value was attained with a cadence of 110 ± 16 rpm (52 ± 5% MDF). The relationship between the MDF and cadence proved to be very strong (R2 = 0.978) and independent of the cyclists' MDF (p = 0.66). Cadence values derived from this relationship revealed a very high test-retest repeatability (mean SEM = 4 rpm, 3.3%) and long-term stability (SEM = 3 rpm, 2.3%); despite increases in the MDF following the 10-week period. Our findings support the validity, reliability and long-term stability of this method for the assessment of the torque-cadence profile and MDF in cyclists.

Is the Functional Threshold Power a Valid Metric to Estimate the Maximal Lactate Steady State in Cyclists?

ABSTRACT: Lillo-Beviá, JR, Courel-Ibáñez, J, Cerezuela-Espejo, V, Morán-Navarro, R, Martínez-Cava, A, and Pallarés, JG. Is the functional threshold power a valid metric to estimate the maximal lactate steady state in cyclists? J Strength Cond Res 36(1): 167-173, 2022-The aims of this study were to determine (a) the repeatability of a 20-minute time-trial (TT20), (b) the location of the TT20 in relation to the main physiological events of the aerobic-anaerobic transition, and (c) the predictive power of a list of correction factors and linear/multiple regression analysis applied to the TT20 result to estimate the individual maximal lactate steady state (MLSS). Under laboratory conditions, 11 trained male cyclists and triathletes (V̇o2max 59.7 ± 3.0 ml·kg-1·min-1) completed a maximal graded exercise test to record the power output associated with the first and second ventilatory thresholds and V̇o2max measured by indirect calorimetry, several 30 minutes constant tests to determine the MLSS, and 2 TT20 tests with a short warm-up. Very high repeatability of TT20 tests was confirmed (standard error of measurement of ±3 W and smallest detectable change of ±9 W). Validity results revealed that MLSS differed substantially from TT20 (bias = 26 ± 7 W). The maximal lactate steady state was then estimated from the traditional 95% factor (bias = 12 ± 7 W) and a novel individual correction factor (ICF% = MLSS/TT20), resulting in 91% (bias = 1 ± 6 W). Complementary linear (MLSS = 0.7488 × TT20 + 43.24; bias = 0 ± 5 W) and multiple regression analysis (bias = 0 ± 4 W) substantially improved the individual MLSS workload estimation. These findings suggest reconsidering the TT20 procedures and calculations to increase the effectiveness of the MLSS prediction.

Reproducibility of the Rotor 2INpower Crankset for Monitoring Cycling Power Output: A Comprehensive Analysis in Different Real-Context Situations.

PURPOSE: To examine the reproducibility (intradevice and interdevice agreement) of the Rotor 2INpower device under a wide range of cycling conditions. METHODS: Twelve highly trained male cyclists and triathletes completed 5 cycling tests, including graded exercise tests at different cadences (70-100 rpm), workloads (100-650 W), pedaling positions (seated and standing), and vibration conditions (20-40 Hz) and an 8-second maximal sprint (>1000 W). An intradevice analysis included a comparison between the power output registered by 3 units of Rotor 2INpower, whereas the power output provided by each one of these units and the gold-standard SRM crankset were compared for the interdevice analysis. Among others, statistical calculations included the standard error of measurement, expressed in absolute (in watts) and relative terms as the coefficient of variation (CV). RESULTS: Except for the graded exercise test seated at 100 rpm/100 W (CV = 10.2%), the intradevice analysis showed an acceptable magnitude of error (CV ≤ 6.9%, standard error of measurement ≤ 12.3 W) between the 3 Rotor 2INpower. Similarly, these 3 units showed an acceptable agreement with the gold standard in all graded exercise test situations (CV ≤ 4.0%, standard error of measurement ≤ 13.1 W). On the other hand, both the intradevice and interdevice agreements proved to be slightly reduced under high cadences (intradevice: CV ≤ 10.2%; interdevice: CV ≤ 4.0%) and vibration (intradevice: CV ≤ 4.0%; interdevice: CV ≤ 3.6%), as well as during standing pedaling (intradevice: CV ≤ 4.1%; interdevice: CV ≤ 2.5%). Although within the limits of an acceptable agreement, measurement errors increased during the sprint tests (CV ≤ 7.4%). CONCLUSIONS: Based on these results, the Rotor 2INpower could be considered a reproducible tool to monitor power output in most cycling situations.

Are the Assioma Favero Power Meter Pedals a Reliable Tool for Monitoring Cycling Power Output?

This study aimed to examine the validity and reliability of the recently developed Assioma Favero pedals under laboratory cycling conditions. In total, 12 well-trained male cyclists and triathletes (VO2max = 65.7 ± 8.7 mL·kg-1·min-1) completed five cycling tests including graded exercises tests (GXT) at different cadences (70-100 revolutions per minute, rpm), workloads (100-650 Watts, W), pedaling positions (seated and standing), vibration stress (20-40 Hz), and an 8-s maximal sprint. Tests were completed using a calibrated direct drive indoor trainer for the standing, seated, and vibration GXTs, and a friction belt cycle ergometer for the high-workload step protocol. Power output (PO) and cadence were collected from three different brand, new pedal units against the gold-standard SRM crankset. The three units of the Assioma Favero exhibited very high within-test reliability and an extremely high agreement between 100 and 250 W, compared to the gold standard (Standard Error of Measurement, SEM from 2.3-6.4 W). Greater PO produced a significant underestimating trend (p < 0.05, Effect size, ES ≥ 0.22), with pedals showing systematically lower PO than SRM (1-3%) but producing low bias for all GXT tests and conditions (1.5-7.4 W). Furthermore, vibrations ≥ 30 Hz significantly increased the differences up to 4% (p < 0.05, ES ≥ 0.24), whereas peak and mean PO differed importantly between devices during the sprints (p < 0.03, ES ≥ 0.39). These results demonstrate that the Assioma Favero power meter pedals provide trustworthy PO readings from 100 to 650 W, in either seated or standing positions, with vibrations between 20 and 40 Hz at cadences of 70, 85, and 100 rpm, or even at a free chosen cadence.

Validity and Reliability of the PowerTap P1 Pedals Power Meter.

To validate the new PowerTap P1® pedals power meter (PP1), thirty-three cyclists performed 12 randomized and counterbalanced graded exercise tests (100-500 W), at 70, 85 and 100 rev·min-1 cadences, in seated and standing positions. A scientific SRM system and a pair of PP1 pedals continuously recorded cadence and power output data. Significantly lower power output values were detected for the PP1 compared to the SRM for all workloads, cadences, and pedalling conditions (2-10 W, p < 0.05), except for the workloads ranged between 150 W to 350 W at 70 rev·min-1 in seated position (p > 0.05). Strong Spearman's correlation coefficients were found between the power output values recorded by both power meters in a seated position, independently from the cadence condition (rho ≥ 0.987), although slightly lower concordance was found for the standing position (rho = 0.927). The mean error for power output values were 1.2%, 2.7%, 3.5% for 70, 85 and 100 rev·min-1, respectively. Bland-Altman analysis revealed that PP1 pedals underestimate the power output data obtained by the SRM device in a directly proportional manner to the cyclist's cadence (from -2.4 W to -7.3 W, rho = 0.999). High absolute reliability values were detected in the PP1 pedals (150-500 W; CV = 2.3%; SEM < 1.0 W). This new portable power meter is a valid and reliable device to measure power output in cyclists and triathletes for the assessment, training and competition using their own bicycle, although caution should be exercised in the interpretation of the results due to the slight power output underestimation of the PP1 pedals when compared to the SRM system and its dependence on both pedalling cadence and cyclist's position (standing vs. seated).