Are Unilateral Devices Valid for Power Output Determination in Cycling? Insights From the Favero Assioma Power Meter.

PURPOSE: Some power meters are available in both bilateral and unilateral versions. However, despite the popularity of the latter, their validity remains unknown. We aimed to analyze the validity of a unilateral pedal power meter for estimating actual ("bilateral") power output (PO). METHODS: Thirty-three male cyclists were assessed at different POs (steady cycling at 100-500 W, as well as all-out sprints), pedaling cadences (70, 85, and 100 repetitions·min-1), and cycling positions (seated and standing). The PO estimated by a left-only power meter (Favero Assioma Uno) was compared with the actual PO computed by a bilateral power meter (Favero Assioma Duo), and the level of bilateral asymmetry (most- vs least-powerful leg) with the latter system was also computed. RESULTS: Nonsignificant differences, high intraclass correlation coefficients (≥.90), and low coefficients of variation (consistently ≤5% except for low PO levels, ie, 5%-7% at 100 W) were found between Favero Assioma Uno and Favero Assioma Duo. However, although a strong intraclass correlation coefficient (.995) was found between both legs, asymmetry values of 4% to 6% were found for all conditions except when pedaling at the lowest PO (100 W), in which asymmetry increased up to 10% to 13%. CONCLUSIONS: Although cyclists tend to present some level of bilateral asymmetry during cycling (particularly at low PO), Favero Assioma Uno provides overall valid estimates of actual PO and is, therefore, an economical alternative to bilateral power meters. Caution is needed, however, when interpreting data at the individual level in cyclists with high levels of asymmetry.

The effect of experience on the psychophysiological response and shooting performance under acute physical stress of soldiers.

Present research studied the psychophysiological response and shooting performance taking into consideration the experience of the soldier after a physical stress protocol, which leaded to acute fatigue conditions. Sixty soldiers were divided into experienced and non-experienced groups to conduct a high-intensity interval training (HIIT) based on endurance type exercises (10 intervals of 40 m run at maximum intensity with 2 changes of direction and 45 s of recovery. Psychophysiological and shooting performance variables were measured before, during and after the HIIT protocol. Significant increases in heart rate, blood lactate, lower limbs strength, as well as a significant decrease in blood oxygen saturation and body temperature were found in both groups. Shooting performance was affected by experience and fatigue, being more accentuated in non-experienced. Present HIIT protocol elicited a similar psychophysiological response than in previously reported combat manoeuvres, thus proving to be an optimal stimuli approach/intervention for soldier's specific physical preparation.

Relationship Between Critical Power and Different Lactate Threshold Markers in Recreational Cyclists.

Purpose: To analyze the relationship between critical power (CP) and different lactate threshold (LT2) markers in cyclists. Methods: Seventeen male recreational cyclists [33 ± 5 years, peak power output (PO) = 4.5 ± 0.7 W/kg] were included in the study. The PO associated with four different fixed (onset of blood lactate accumulation) and individualized (Dmaxexp, Dmaxpol, and LTΔ1) LT2 markers was determined during a maximal incremental cycling test, and CP was calculated from three trials of 1-, 5-, and 20-min duration. The relationship and agreement between each LT2 marker and CP were then analyzed. Results: Strong correlations (r = 0.81-0.98 for all markers) and trivial-to-small non-significant differences (Hedges' g = 0.01-0.17, bias = 1-9 W, and p > 0.05) were found between all LT2 markers and CP with the exception of Dmaxexp, which showed the strongest correlation but was slightly higher than the CP (Hedges' g = 0.43, bias = 20 W, and p < 0.001). Wide limits of agreement (LoA) were, however, found for all LT2 markers compared with CP (from ±22 W for Dmaxexp to ±52 W for Dmaxpol), and unclear to most likely practically meaningful differences (PO differences between markers >1%, albeit <5%) were found between markers attending to magnitude-based inferences. Conclusion: LT2 markers show a strong association and overall trivial-to-small differences with CP. Nevertheless, given the wide LoA and the likelihood of potentially meaningful differences between these endurance-related markers, caution should be employed when using them interchangeably.

Performance Parameters in Competitive Alpine Skiing Disciplines of Slalom, Giant Slalom and Super-Giant Slalom.

The objective of this study was to describe the kinematic patterns and impacts in male and female skiers in the super-giant slalom, giant slalom and slalom disciplines of an international alpine skiing competition using a portable Global Navigation Satellite Systems (GNSS) technology device. Fifteen skiers (males, n = 9, females, n = 6) volunteered to participate in this study. Data acquisition was carried out using a wireless inertial measurement device (WIMUTM PRO: hybrid location system GNSS at 18 Hz with a precision locator UltraWideband UWD (<10 cm) and 3D accelerometers 1000 Hz) where distances covered in different speed and acceleration thresholds and impacts above 5g were recorded in each of the disciplines. Male and female alpine skiers showed different physical parameters and impacts even though they competed in the same courses in the disciplines of slalom, giant slalom and super-giant slalom (total impacts: p < 0.001; impacts > 7 g: p = 0.013; impacts 6.1-7 g: p = 0.002; impacts 5.1-6 g: p = 0.006). In male skiers, the distances traveled at different speed thresholds have a direct relation to the ranking of skiers, but this ideal threshold decreased as the technicality of the discipline increased. In the case of female skiers, although no relation was seen with the speed thresholds, greater distances covered at medium accelerations improved skiing performance. The external load in alpine skiing varied based on sex and discipline. This information could be essential to develop sex-specific and discipline-specific training programs in alpine skiing.

Validity of the Favero Assioma Duo Power Pedal System for Measuring Power Output and Cadence.

Cycling power meters enable monitoring external loads and performance changes. We aimed to determine the concurrent validity of the novel Favero Assioma Duo (FAD) pedal power meter compared with the crank-based SRM system (considered as gold standard). Thirty-three well-trained male cyclists were assessed at different power output (PO) levels (100-500 W and all-out 15-s sprints), pedaling cadences (75-100 rpm) and cycling positions (seating and standing) to compare the FAD device vs. SRM. No significant differences were found between devices for cadence nor for PO during all-out efforts (p > 0.05), although significant but small differences were found for efforts at lower PO values (p < 0.05 for 100-500 W, mean bias 3-8 W). A strong agreement was observed between both devices for mean cadence (ICC > 0.87) and PO values (ICC > 0.81) recorded in essentially all conditions and for peak cadence (ICC > 0.98) and peak PO (ICC > 0.99) during all-out efforts. The coefficient of variation for PO values was consistently lower than 3%. In conclusion, the FAD pedal-based power meter can be considered an overall valid system to record PO and cadence during cycling, although it might present a small bias compared with power meters placed on other locations such as SRM.

Traditional Versus Velocity-Based Resistance Training in Competitive Female Cyclists: A Randomized Controlled Trial.

We assessed the effects of a short-term velocity-based resistance training (VBRT, where exercise intensity is individualized based on the loads and repetitions that maximize power output) program compared with traditional resistance training (TRT, where the same number of repetitions and relative load are used for every individual) on body composition, muscle strength/power, and endurance performance in competitive female cyclists. Seventeen participants were randomly assigned to 6 weeks (two sessions/week) of TRT (n = 8) or VBRT (n = 9), during which they maintained their usual endurance program. Both interventions included squat, hip thrust, and split squat exercises. Training loads were continuously registered, and outcomes were measures of muscle strength/power, body composition, and endurance performance (incremental test and 8-min time trial). No differences between TRT and VBRT groups were found for overall internal training loads during resistance training or cycling sessions (p > 0.05). Both interventions led to significant improvements in all strength/power-related outcomes, but VBRT induced greater improvements than TRT in maximum muscle strength and power as assessed with the hip thrust exercise (p < 0.05 for the group by time interaction effect). However, no significant group by time interaction effect was found for body composition or endurance performance-related outcomes. In conclusion, the addition of a short-term intervention of VBRT or TRT to the usual training regimen of competitive female cyclists improves muscle strength/power, albeit VBRT might induce superior gains on maximum strength/power for the hip thrust exercise.

On- Versus Off-Bike Power Training in Professional Cyclists: A Randomized Controlled Trial.

PURPOSE: To compare the effectiveness of resistance power training (RPT, training with the individualized load and repetitions that maximize power output) and cycling power training (CPT, short sprint training) in professional cyclists. METHODS: The participants (20 [2] y, peak oxygen uptake 78.0 [4.4] mL·kg-1·min-1) were randomly assigned to perform CPT (n = 8) or RPT (n = 10) in addition to their usual training regime for 7 weeks (2 sessions/wk). The training loads were continuously registered using the session rating of perceived exertion. The outcomes included endurance performance (8-min time trial and incremental test), as well as measures of muscle strength/power (1-repetition maximum and mean maximum propulsive power on the squat, hip thrust, and lunge exercises) and body composition (assessed by dual-energy X-ray absorptiometry). RESULTS: No between-group differences were found for training loads or for any outcome (P > .05). Both interventions resulted in increased time-trial performance, as well as in improvements in other endurance-related outcomes (ie, ventilatory threshold, respiratory compensation point; P < .05). A significant or quasi-significant increase (P = .068 and .047 for CPT and RPT, respectively) in bone mineral content was observed after both interventions. A significant reduction in fat mass (P = .017), along with a trend (P = .059) toward a reduced body mass, was observed after RPT, but not CPT (P = .076 for the group × time interaction effect). Significant benefits (P < .05) were also observed for most strength-related outcomes after RPT, but not CPT. CONCLUSION: CPT and RPT are both effective strategies for the improvement of endurance performance and bone health in professional cyclists, although the latter tends to result in greater improvements in body composition and muscle strength/power.

Traditional Versus Optimum Power Load Training in Professional Cyclists: A Randomized Controlled Trial.

PURPOSE: To compare the effectiveness of optimum power load training (OPT, training with an individualized load and repetitions that maximize power output) and traditional resistance training (TRT, same number of repetitions and relative load for all individuals) in professional cyclists. METHODS: Participants (19 [1] y, peak oxygen uptake 75.5 [6] mL/kg/min) were randomly assigned to 8 weeks (2 sessions per week) of TRT (n = 11) or OPT (n = 9), during which they maintained their usual cycle training schedule. Training loads were continuously registered, and measures of muscle strength/power (1-repetition maximum and maximum mean propulsive power on the squat, hip thrust, and lunge exercises), body composition (assessed by dual-energy X-ray absorptiometry), and endurance performance (assessed on both an incremental test and an 8-min time trial) were collected before and at the end of the intervention. RESULTS: OPT resulted in a lower average intensity (percentage of 1-repetition maximum) during resistance training sessions for all exercises (P < .01), but no differences were found for overall training loads during resistance or cycling sessions (P > .05). Both programs led to significant improvements in all strength/power-related parameters, muscle mass (with no changes in total body mass but a decreased fat mass), and time-trial performance (all Ps < .05). A trend toward increased power output at the respiratory compensation point was also found (P = .056 and .066 for TRT and OPT, respectively). No between-groups differences were noted for any outcome (P > .05). CONCLUSION: The addition of either TRT or OPT to an endurance training regimen of elite cyclists results in similar improvements of body composition, muscle strength/power, and endurance performance.

Functional Threshold Power: Relationship With Respiratory Compensation Point and Effects of Various Warm-Up Protocols.

PURPOSE: The functional threshold power (FTP), which demarcates the transition from steady state to non-steady-state oxidative metabolism, is usually determined with a 20-minute cycling time trial that follows a standard ∼45-minute warm-up. This study aimed to determine if the standard warm-up inherent to FTP determination is actually necessary and how its modification or removal affects the relationship between FTP and the respiratory compensation point (RCP). METHODS: A total of 15 male cyclists (age 35 [9] y, maximum oxygen uptake 66.4 [6.8] mL·kg-1·min-1) participated in this randomized, crossover study. Participants performed a ramp test for determination of RCP and maximum oxygen uptake. During subsequent visits, they performed a 20-minute time trial preceded by the "standard" warm-up that is typically performed before an FTP test (S-WU), a 10-minute warm-up at the power output (PO) corresponding to 60% of maximum oxygen uptake (60%-WU), or no warm-up (No-WU). FTP was computed as 95% of the mean PO attained during the time trial. RESULTS: Although the FTP was correlated with the RCP independently of the warm-up (r = .89, .93, and .86 for No-WU, 60%-WU, and S-WU, respectively; all Ps < .001), the PO at RCP was higher than the FTP in all cases (bias ± 95% limits of agreement = 57 [24], 60 [23], and 57 [32] W for No-WU, 60%-WU, and S-WU, respectively; all Ps < .001 and effect size > 1.70). CONCLUSIONS: The FTP is highly correlated with the RCP but corresponds to a significantly lower PO, being these results independent of the warm-up performed (or even with no warm-up).

Physiological Predictors of Competition Performance in CrossFit Athletes.

The aim of this study was to determine the physiological variables that predict competition performance during a CrossFit competition. Fifteen male amateur CrossFit athletes (age, 35 ± 9 years; CrossFit experience, 40 ± 27 months) performed a series of laboratory-based tests (incremental load test for deep full squat and bench press; squat, countermovement and drop jump tests; and incremental running and Wingate tests) that were studied as potential predictors of CrossFit performance. Thereafter, they performed the five Workouts of the Day (WODs) corresponding to the CrossFit Games Open 2019, and we assessed the relationship between the laboratory-based markers and CrossFit performance with regression analyses. Overall CrossFit performance (i.e., final ranking considering the sum of all WODs, as assessed by number of repetitions, time spent in exercises or weight lifted) was significantly related to jump ability, mean and peak power output during the Wingate test, relative maximum strength for the deep full squat and the bench press, and maximum oxygen uptake (VO2max) and speed during the incremental test (all p < 0.05, r = 0.58-0.75). However, the relationship between CrossFit Performance and most laboratory markers varied depending on the analyzed WOD. Multiple linear regression analysis indicated that measures of lower-body muscle power (particularly jump ability) and VO2max explained together most of the variance (R2 = 81%, p < 0.001) in overall CrossFit performance. CrossFit performance is therefore associated with different power-, strength-, and aerobic-related markers.

Warming Up Before a 20-Minute Endurance Effort: Is It Really Worth It?

PURPOSE: To analyze the effects of different warm-up protocols on endurance-cycling performance from an integrative perspective (by assessing perceptual, neuromuscular, physiological, and metabolic variables). METHODS: Following a randomized crossover design, 15 male cyclists (35 [9] y; peak oxygen uptake [VO2peak] 66.4 [6.8] mL·kg-1·min-1) performed a 20-minute cycling time trial (TT) preceded by no warm-up, a standard warm-up (10 min at 60% of VO2peak), or a warm-up that was intended to induce potentiation postactivation (PAP warm-up; 5 min at 60% of VO2peak followed by three 10-s all-out sprints). Study outcomes were jumping ability and heart-rate variability (both assessed at baseline and before the TT), TT performance (mean power output), and perceptual (rating of perceived exertion) and physiological (oxygen uptake, muscle oxygenation, heart-rate variability, blood lactate, and thigh skin temperature) responses during and after the TT. RESULTS: Both standard and PAP warm-up (9.7% [4.7%] and 12.9% [6.5%], respectively, P < .001), but not no warm-up (-0.9% [4.8%], P = .074), increased jumping ability and decreased heart-rate variability (-7.9% [14.2%], P = .027; -20.3% [24.7%], P = .006; and -1.7% [10.5%], P = .366). Participants started the TT (minutes 0-3) at a higher power output and oxygen uptake after PAP warm-up compared with the other 2 protocols (P < .05), but no between-conditions differences were found overall for the remainder of outcomes (P > .05). CONCLUSIONS: Compared with no warm-up, warming up enhanced jumping performance and sympathetic modulation before the TT, and the inclusion of brief sprints resulted in a higher initial power output during the TT. However, no warm-up benefits were found for overall TT performance or for perceptual or physiological responses during the TT.

Validity of a novel device for real-time analysis of cyclists' drag area.

OBJECTIVES: To assess the reliability, validity, and sensitivity of a novel device (Notio Konect™) which is purported to provide a real-time analysis of aerodynamic drag area (CdA) during cycling. DESIGN: Observational, cross-sectional study. METHODS: Fifteen trained cyclists rode in an indoor velodrome using three different positions (upright, aero [holding aero bars], and optimized aero [similar to aero, but wearing a time-trial helmet]). They completed six 1-min trials in each position. The CdA was measured with Notio and with two other systems (Track Aero System™ [TAS] and a validated mathematical model). RESULTS: The CdA measured with Notio showed good reliability (intra-class correlation coefficient [ICC]=0.92, 90% confidence interval [CI]=0.89-0.95). Notio showed an almost perfect relationship with both TAS (ICC=0.99, 90% CI=0.98-0.99) and the mathematical model (ICC=0.99, 90% CI=0.98-0.99). However, the CdA values provided by the former (0.308±0.051m2) were significantly higher (albeit with a trivial effect size [ES]) compared with TAS (0.300±0.051m2, p<0.001, ES=0.15) and the mathematical model (0.303±0.051m2, p=0.005, ES=0.09). The CdA was higher in the upright than in the aero position with all systems (all p<0.001, ES=1.84-1.89), and higher in the aero than in the optimized aero position when measured with TAS (p=0.033, ES=0.22) or the mathematical model (p=0.024, ES=0.24), but not with Notio (p=0.220, ES=0.19). CONCLUSIONS: Notio appears to be reliable, strongly correlated to other established systems, and discerns large (upright vs aero) but not small (aero vs optimized aero) variations in riding position. Further research is needed to confirm its validity in outdoor conditions.