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This study aimed to investigate the effects of caffeine ingestion by chewing gum (GUMCAF) combined with priming exercise on pulmonary oxygen uptake ( V ˙ O 2 ) and near-infrared spectroscopy-derived muscle oxygen extraction (HHb + Mb) kinetics during cycling performed in a severe-intensity domain. Fifteen trained cyclists completed four visits: two under a placebo gum (GUMPLA) and two under GUMCAF ingestion. Each visit consisted of two square-wave cycling bouts at Δ70 intensity (70% of difference between the V ˙ O 2 at first ventilatory threshold and V ˙ O 2 max) with duration of 6 min each and 5 min of passive rest between the bouts. The GUMPLA or GUMCAF (400 mg) was chewed for 5 min, 12 min before the first Δ70 bout in a randomized double-blind procedure. The fundamental phase and slow component of HHb + Mb and V ˙ O 2 kinetics were evaluated. For HHb + Mb kinetics, regardless of ingested gum, priming exercise effects occurred on the time constant (GUMCAF 16.0 ± 4.0 vs. 13.9 ± 2.9 s; GUMPLA 15.7 ± 6.1 vs. 13.2 ± 2.5 s), amplitude, slow component, time delay, and mean response time parameters (p ≤.032). For V ˙ O 2 kinetics, there were significant effects of bouts on the amplitude, slow component, end V ˙ O 2 , and the gain kinetics parameters (p <.017). Baseline V ˙ O 2 was higher during GUMCAF than GUMPLA (p =.020). No significant effects occurred for the interaction between gum and bout in any parameter of V ˙ O 2 or HHb + Mb kinetics. Therefore, unlike the priming exercise in severe-intensity exercise, GUMCAF is not an effective strategy for improving V ˙ O 2 or HHb + Mb kinetics acceleration. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this investigation was to assess alterations of pulmonary oxygen uptake ( V ˙ O 2 ) and muscle deoxygenation on-kinetics during heavy-intensity cycling in youth cyclists over a period of 15 months. Methods: Eleven cyclists (initial age, 14.3 [1.6] y; peak V ˙ O 2 , 62.2 [4.5] mL·min−1·kg−1) visited the laboratory twice on 3 occasions within 15 months. Participants performed an incremental ramp exercise test and a constant workrate test within the heavy-intensity domain during the first visit and second visit, respectively. Subsequently, parameter estimates of the V ˙ O 2 and muscle deoxygenation on-kinetics were determined with mono-exponential models. Results: The V ˙ O 2 phase II time constant decreased from occasion 1 (34 [4] s) to occasion 2 (30 [4] s, P =.005) and 3 (28 [4] s, P =.010). However, no significant alteration was observed between occasions 2 and 3 (P =.565). The V ˙ O 2 slow component amplitude either expressed in absolute values (ie, L·min−1) or relative to end exercise V ˙ O 2 (ie, %) showed no significant changes throughout the study (P =.972 and.996). Furthermore, the muscle deoxygenation on-kinetic mean response time showed no significant changes throughout the study (18 [8], 18 [3], and 16 [5] s for occasions 1, 2, and 3, respectively; P =.279). Conclusion: These results indicate proportional enhancements of local muscle oxygen distribution and utilization, which both contributed to the speeding of the V ˙ O 2 on-kinetics herein. [ABSTRACT FROM AUTHOR]

Purpose: To describe and compare the race characteristics, demands, and durability profile of a male and a female Grand Tour winner. Methods: Overall and stage-type-specific (ie, time trials, flat, semimountainous, and mountain) demands and race characteristics during 2 Grand Tours were determined and compared between the female and male cyclists. In addition, relative power output distribution and pacing, percentage of functional threshold power (FTP), and changes in maximal mean power outputs (MMPs) with increasing levels of kilojoules burned were determined. Results: Although many differences were found between course and absolute racing demands between the male (FTP: 413 W; critical power: 417 W) and female (FTP: 297 W; critical power: 297 W) cyclists, similar power distributions and pacing strategies were found if data were expressed relatively. However, the female cyclist rode a higher percentage of her FTP during the first 2 quarters of flat stages (14.7%–15.1%) and the last quarter of mountain stages (9.8%) than the male cyclist. Decrements in MMPs were only observed after burning 30 kJ·kg−1 in the female and 45 kJ·kg−1 in the male Grand Tour winner. Conclusions: Both the male and female Grand Tour winners produced very high 20- to 60-minute MMPs, whereas decrements in MMPs were only observed after having burned 75% (female) and 80% (male) of total kilojoules burned during a stage. These are the latest and lowest in MMPs reported in the scientific literature and highlight the importance of durability in combination with excellent climbing and time-trial skills, which are needed to be able to win a Grand Tour. [ABSTRACT FROM AUTHOR]

Background: It is essential to better characterize the energetic profile of individuals during very low-intensity physical activity. The objectives of the present study were to determine whether the saver profile from sit-to-stand persists during light physical activity and characterize patterns in substrate utilization from sit-to-stand and during very low-intensity physical activity in healthy men and women. Methods: Sixty-two healthy adults (38 women) performed an experimental sequence that corresponded to 15-minute sitting (SIT1), followed by 15-minute standing (STAND), 15-minute sitting again (SIT2), and finally 15 minutes of light cycling. Continuous indirect calorimetry was allowed to calculate energy expenditure (EE) and respiratory quotient through the entire sequence. Savers and nonsavers (<5% and ≥ 5% increase in EE from sitting to standing, respectively) were determined. Results: There was an interaction effect in EE between savers and nonsavers through the whole sequence (P =.008). Only nonsavers (71%) exhibited a significant increase in EE from SIT1 to STAND (P <.001). Nonsavers and savers significantly increased EE during 15 minutes of light cycling relative to sitting or standing (P <.001), without any difference between groups. The percentage of change in respiratory quotient from SIT1 to STAND was significantly different between the 2 groups, with increased values in savers and decreased values in nonsavers (P =.03). Significantly lower values in respiratory quotient and EE were found during 15 minutes of light cycling in women compared with men (P <.001). Conclusions: It is essential to determine individuals' energetic phenotype to determine those who may benefit more from strategies such as standing or light physical activity. The sexual dimorphism in terms of substrate use during such exercise should be considered. [ABSTRACT FROM AUTHOR]

Purpose: To compare the training characteristics of an elite team pursuit cycling squad in the 3-month preparation phases prior to 2 successive world-record (WR) performances. Methods: Training data of 5 male track endurance cyclists (mean [SD]; age 23.4 [3.46] y; body mass 80.2 [2.74] kg; 4.5 [0.17] W·kg−1 at LT2; maximal aerobic power 6.2 [0.27] W·kg−1; maximal oxygen uptake 65.9 [2.89] mL·kg−1·min−1) were analyzed with weekly total training volume by training type and heart rate, power output, and torque intensity distributions calculated with reference to the respective WRs' performance requirements. Results: Athletes completed 805 (82.81) and 725 (68.40) min·wk–1 of training, respectively, in each season. In the second season, there was a 32% increase in total track volume, although track sessions were shorter (ie, greater frequency) in the second season. A pyramidal intensity distribution was consistent across both seasons, with 81% of training, on average, performed below LT1 power output each week, whereas 6% of training was performed above LT2. Athletes accumulated greater volume above WR team pursuit lead power (2.4% vs 0.9%) and torque (6.2% vs 3.2%) in 2019. In one athlete, mean single-leg-press peak rate of force development was 71% and 46% higher at mid- and late-phases, respectively, during the preparation period. Conclusions: These findings provide novel insights into the common and contrasting methods contributing to successive WR team pursuit performances. Greater accumulation of volume above race-specific power and torque (eg, team pursuit lead), as well as improved neuromuscular force-generating capacities, may be worthy of investigation for implementation in training programs. [ABSTRACT FROM AUTHOR]

Purpose: To profile the training characteristics of an elite team pursuit cycling squad and assess variations in training intensity and load accumulation across the 36-week period prior to a world-record performance at the 2018 Commonwealth Games. Methods: Training data of 5 male track endurance cyclists (mean [SD]; age 21.9 [3.52] y; 4.4 [0.16] W·kg−1 at anaerobic threshold; 6.2 [0.28] W·kg−1 maximal oxygen uptake 68.7 [2.99] mL kg·min−1) were analyzed with weekly total training volume and heart rate, power output, and torque intensity distributions calculated with reference to their 3:49.804 min:s.ms performance requirements for a 4-km team pursuit. Results: Athletes completed 543 (37) h−1 of training across 436 (16) sessions. On-bike activities accounted for 69.9% of all training sessions, with participants cycling 11,246 (1139) km−1 in the training period of interest, whereas 12.7% of sessions involved gym/strength training. A pyramidal intensity distribution was evident with over 65% and 70% of training, respectively, performed at low-intensity zone heart rate and power output, whereas 5.3% and 7.7% of training was performed above anaerobic threshold. The athletes accumulated 4.4% of total training volume at, or above, their world-record team pursuit lead position torque (55 N·m). Conclusions: These data provide updated and novel insight to the power and torque demands and load accumulation contributing to world-record team pursuit performance. Although the observed pyramidal intensity distribution is common in endurance sports, the lack of shift toward a polarized intensity distribution during taper and competition peaking differs from previous research. [ABSTRACT FROM AUTHOR]

Purpose: To assess the effect of 2 work-matched efforts of different intensities on subsequent performance in well-trained cyclists. Methods: The present study followed a randomized controlled crossover design. Twelve competitive junior cyclists volunteered to participate (age, 17 [1] y; maximum oxygen uptake, 71.0 [4.7] mL·kg−1·min−1). The power–duration relationship was assessed through 2-minute, 5-minute, and 12-minute field tests under fresh conditions (control). On subsequent days and following a randomized order, participants repeated the aforementioned tests after 2 training sessions matched for mechanical work (∼15 kJ/kg) of different intensities (ie, a moderate-intensity continuous-training [60%–70% of critical power; CP] session or a session including high-intensity intervals [3-min repetition bouts at 110%–120% of the CP interspersed by 3-min rest periods]). Results: A significantly lower power output was found in the 2-minute test after the high-intensity training session compared not only with the control condition (−8%, P <.001) but also with the moderate-intensity continuous-training session (−7%, P =.003), with no significant differences between the latter conditions. No significant differences between conditions were found for the remaining tests. As a consequence, the high-intensity training session resulted in significantly lower W′ values compared to both the control condition (−27%, P =.001) and the moderate-intensity continuous-training session (−26%, P =.012), with no differences between the 2 latter conditions and with no differences for CP. Conclusion: A session including high-intensity intermittent efforts induces a greater fatigue, particularly in short-duration efforts and W′, than a work-matched continuous-training session of moderate intensity. [ABSTRACT FROM AUTHOR]

Background: Spiroergometry is important for modern performance diagnostics, and reference values have been evaluated for bicycle and treadmill ergometers. The aim of this study is to assess the comparability of bicycle and hand-crank spiroergometry and its associated parameters, as hand-crank spiroergometry can be used during rehabilitation in patients with definitive or temporally impairment of the lower extremity. Methods: Thirty-seven healthy volunteers completed 2 exhausting performance diagnostics on hand-crank and bicycle spiroergometry. Participants' anthropometric characteristics, maximum power, multiple exertion criteria, maximum aerobic capacity, and maximum heart rate were detected, and ventilatory and metabolic thresholds were determined. Results: The maximum power, maximum heart rate, maximum aerobic capacity, and ventilatory thresholds were significant higher on the bicycle ergometer (P <.001). The metabolic thresholds occurred on higher lactate values on the hand-crank ergometer. Equations for calculating maximum aerobic capacity from the maximum power measured in either hand-crank or bicycle ergometer could be found through regression analysis. Conclusions: Although there are problems in interpreting results of different ergometries due to severe physiology differences, the equations can be used for patients who are temporally unable to complete the established ergometry due to a deficit in the lower extremity. This could improve training recommendations for patients and para-athletes in particular. [ABSTRACT FROM AUTHOR]

Postexercise hydration is fundamental to replace fluid loss from sweat. This study evaluated rehydration and gastrointestinal (GI) symptoms for each of three beverages: water (W), sports drink (SD), and skimmed, lactose-free milk (SLM) after moderate-intensity cycling in the heat. Sixteen college students completed three exercise sessions each to lose ≈2% of their body mass. They drank 150% of body mass loss of the drink assigned in randomized order; net fluid balance, diuresis, and GI symptoms were measured and followed up for 3 hr after completion of fluid intake. SLM showed higher fluid retention (∼69%) versus W (∼40%; p <.001); SD (∼56%) was not different from SLM or W (p >.05). Net fluid balance was higher for SLM (−0.26 kg) and SD (−0.42 kg) than W (−0.67 kg) after 3 hr (p <.001), resulting from a significantly lower diuresis with SLM. Reported GI disturbances were mild and showed no difference among drinks (p >.05) despite ingestion of W (1,992 ± 425 ml), SD (1,999 ± 429 ml), and SLM (1,993 ± 426 ml) in 90 min. In conclusion, SLM was more effective than W for postexercise rehydration, showing greater fluid retention for the 3-hr follow-up and presenting with low-intensity GI symptoms similar to those with W and SD. These results confirm that SLM is an effective option for hydration after exercise in the heat. [ABSTRACT FROM AUTHOR]

Despite the increased popularity of female elite road cycling, research to inform the fueling requirements of these endurance athletes is lacking. In this case study, we report for the first time the energetics of a female world-tour cyclist competing in the 2023 Tour de France Femmes, an 8-day race of the Union Cycliste Internationale. The 29-year-old athlete presented with oligomenorrhea and low T3 before the race. Total daily energy expenditure assessed with the doubly labeled water technique was 7,572 kcal/day (∼4.3 physical activity levels), among the highest reported in the literature to date for a female. Crank-based mean maximal power was consistent with female world-tour cyclists (5 min, mean 342 W, 4.8 W/kg; 20 min 289 W, 4.1 W/kg). The average daily energy intake measured with the remote food photography method (Stage Days 1–7) was 5,246 kcal and carbohydrate intake was 13.7 g/kg (range 9.7–15.9 g/kg), and 84 g/hr during stages, and an average fat intake of 15% of daily energy intake. An estimated 2,326 kcal/day energy deficit was evidenced in a 2.2 kg decrease in body mass. Notwithstanding the high carbohydrate intake, the athlete was unable to match the energy requirements of the competition. Despite signs of energy deficiency preexisting (oligomenorrhea and low T3), and other further developing during the race (weight loss), performance was in line with that of other world-tour cyclists and a best personal performance was recorded for the last stage. This case study emphasizes the need for further research to inform energy requirements for female athletes' optimal performance and health. [ABSTRACT FROM AUTHOR]

Background: Bicycling is a healthy form of physical activity that can be performed by most adults as part of leisure-time (LT) activity. However, little is known about LT bicycling behaviors, especially in the rural areas of the United States. This study sought to contrast the prevalence and factors associated with LT bicycling in populations living in urban settings with those living in rural settings. Methods: The 2019 Behavior Risk Factor Survey, which contains information regarding LT physical activity behaviors among adults (N = 396,261) in the United States, was used to determine the prevalence, demographic profile, and likelihood of meeting the physical activity guidelines of LT bicyclists. The 2013 National Center for Health Statistics Urban/Rural Classification Scheme was used to classify respondents living in rural and urban settings. Results: Among US adults, 3.8% (95% CI, 3.7–3.9) reported LT bicycling activity, the sixth most common physical activity. Adults living in urban counties compared with rural counties had a greater prevalence of LT bicycling (3.9% vs 2.3%, respectively), with adults living in rural counties having a 34% lower probability of LT bicycling. Rural bicycling prevalence rates were lower across all demographics. Urban bicyclists, compared with rural bicyclists, cycled more months of the year. Overall, 85.5% of all bicyclists met the aerobic physical guidelines, with no differences between urban and rural bicyclists. Conclusions: Bicycling remains an important LT physical activity among adults in the United States. However, a rural–urban difference in the prevalence does exist for LT bicycling. The reasons for this disparity warrant further investigation. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to determine whether the initial levels of aerobic fitness and hematological variables in young female road cyclists are related to their athletic performance development during their careers. Methods: Results of graded exercise tests on a cycle ergometer and total hemoglobin mass (tHb-mass) measurements were analyzed in 34 female road cyclists (age 18.6 [1.9] y). Among them, 2 groups were distinguished based on their competitive performance (Union Cycliste Internationale world ranking) over the following 8 years. Areas under the curve in receiver-operating-characteristic curves were calculated as indicators of elite-performance prediction. Results: Initial graded exercise test variables (peak power, peak oxygen uptake, and power at 4 mmol/L blood lactate) were not significantly different in elite (n = 13) versus nonelite (n = 21) riders. In contrast, elite riders had higher tHb-mass expressed either in absolute measures (664 [75] vs 596 [59] g, P =.006) or normalized to body mass (11.2 [0.8] vs 10.3 [0.7] g/kg, P =.001) and fat-free mass (14.4 [0.9] vs 13.1 [0.9] g/kg, P <.001). Absolute and relative erythrocyte volumes were significantly higher in elite subjects (P ranged from <.001 to.006). Of all the variables analyzed, the relative tHb-mass had the highest predictive ability to reach the elite level (area under the curve ranged from.82 to.85). Conclusion: Measurement of tHb-mass can be a helpful tool in talent detection to identify young female road cyclists with the potential to reach the elite level in the future. [ABSTRACT FROM AUTHOR]

Background: Active transportation (AT), described as self-powered modes of travel (eg, walking and cycling), is an important source of health-promoting physical activity. While AT behaviors have been measured on national health surveys in Canada for over 2 decades, historic prevalence has not been previously reported. We aimed to document the measures of AT on Canada's various national health surveys, examine AT over time, and interpret them within the context of evolving methods of assessment. Methods: We compiled and summarized the questions used to measure AT among Canadians on 4 national health surveys: National Population Health Survey (1994–1998), Canadian Community Health Survey (2000–2020), Canadian Health Measures Survey (2007–2019), and the Health Behaviour in School-aged Children Study (2010–2018). Among youth and adults (12+ y), we summarized over time: (1) the prevalence of AT participation and (2) time spent in AT (in hours per week) among those who report any AT participation. Where possible, we reported separate estimates of walking and cycling and produced an aggregate estimate of total AT. We stratified results by age group and sex. Results: Changes in AT survey questions over time and between surveys limit the interpretation and comparability of temporal trends. Nevertheless, a consistently higher proportion of females report walking, while a higher proportion of males report cycling. Irrespective of mode, males report spending more total time in AT. Participation in AT tends to decrease with age, with youth reporting the highest rates of AT and young adults often spending the most time in AT. Conclusions: Monitoring trends in AT can help assess patterns of behavior and identify whether promotion strategies are needed or whether population interventions are effective. Our evaluation of AT over time is limited by questions surveyed; however, consistent differences in AT by age and sex are evident over time. Moving forward, ensuring consistency of AT measurement over time is essential to monitoring this important behavior. [ABSTRACT FROM AUTHOR]

Purpose: To investigate how cycling time-trial (TT) performance changes over a cycling season, both in a "fresh" state and in a "fatigued" state (durability). Additionally, the aim was to explore whether these changes are related to changes in underlying physiological factors such as gross efficiency, energy expenditure (EE), and substrate oxidation (fat oxidation [FatOx] and carbohydrate oxidation [CarbOx]). Methods: Sixteen male semiprofessional cyclists visited the laboratory on 3 occasions during a cycling season (PRE, START, and IN) and underwent a performance test in both fresh and fatigued states (after 38.1 [4.9] kJ/kg), containing a submaximal warm-up for the measurement of gross efficiency, EE, FatOx, and CarbOx and a maximal TT of 1 (TT1min) and 10 minutes (TT10min). Results were compared across states (fresh vs fatigued) and periods (PRE, START, and IN). Results: The average power output (PO) in TT1min decreased (P <.05) from fresh to fatigued state across all observed periods, whereas there was no change in the PO in TT10min. Over the course of the season, the PO in TT1min in the fatigued state improved more compared with the PO in TT1min in the fresh state. Furthermore, while EE did not significantly change, there was an increase in FatOx and a decrease in CarbOx toward the fatigued state. These changes diminished during the cycling season (IN), indicating a greater contribution of CarbOx in the fatigued state. Conclusions: TT1min performance is more sensitive to fatigue compared with TT10min. Also, during a cycling season, durability improves more when compared with fresh maximal POs, which is also observed in the changes in substrate oxidation. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the influence of shorter, more frequent rest breaks with per-cooling as an alternative heat-acclimation session on physiological, perceptual, and self-paced maximal cycling performance, compared with continuous heat exposure. Methods: Thirteen participants completed 1 continuous and 3 intermittent-heat-exposure (IHE) maximal self-paced cycling protocols in a random order in heat (36 °C, 80% relative humidity): 1 × 60-minute exercise (CON), 3 × 20-minute exercise with 7.5-minute rest between sets (IHE-20), 4 × 15-minute exercise with 5-minute rest between sets (IHE-15), and 6 × 10-minute exercise with 3-minute rest between sets (IHE-10). Mixed-method per-cooling (crushed-ice ingestion and cooling vest) was applied during rest periods of all IHE protocols. Results: Total distance completed was greater in IHE-10, IHE-15, and IHE-20 than in CON (+11%, +9%, and +8%, respectively), with no difference observed between IHE protocols. Total time spent above 38.5 °C core temperature was longer in CON compared with IHE-15 and IHE-20 (+62% and +78%, respectively) but similar to IHE-10 (+5%). Furthermore, a longer time above 38.5 °C core temperature occurred in IHE-10 versus IHE-15 and IHE-20 (+54% and +69%, respectively). Sweat loss did not differ between conditions. Conclusion: IHE with per-cooling may be a viable alternative heat-acclimation protocol in situations where training quality takes precedence over thermal stimulus or when both factors hold equal priority. [ABSTRACT FROM AUTHOR]

Background: The force–velocity relationship suggests that maximal power (Pmax) can only be produced in optimal torque (Topt) and cadence (Copt). However, the cadence at which mean maximal power (MMP) is produced has never been studied. This study aimed to determine the individual MMP–cadence relationship from in situ data. Method: We analyzed 1 year of data from 14 under-19 cyclists and calculated the MMP for each cadence between 50 and 120 rpm for 2-, 5-, and 20-minute durations. The MMP–cadence relationship was fit with a second-order polynomial function. The goodness of fit (r2) and odd-day–even-day absolute and relative reliability were evaluated, respectively, for Pmax, Topt, and Copt. Results: The goodness of fit was very high for every duration studied. Topt and Pmax, but not Copt, were significantly higher for shorter durations. Pmax was significantly correlated only with Topt for the 3 durations (r2 =.63,.71, and.64 for 2, 5, and 20 min, respectively). Discussion: Evaluation of the MMP–cadence relationship from in situ data is feasible and reliable for 2-, 5-, and 20-minute durations. This profiling approach would enable better detection of the strengths and weaknesses of cyclists and make it possible to design more effective training interventions. Practical Applications: The analysis makes it possible to identify the torque versus cadence component that individually limits power production. Knowing the Copt for a given duration of maximal effort could help athletes choose the right gear ratio and regulate cadence during a race in order to maximize performance. [ABSTRACT FROM AUTHOR]

The cyclical changes in sex hormones across the menstrual cycle (MC) are associated with various biological changes that may alter resting metabolic rate (RMR) and body composition estimates. Hormonal contraceptive (HC) use must also be considered given their impact on endogenous sex hormone concentrations and synchronous exogenous profiles. The purpose of this study was to determine if RMR and dual-energy X-ray absorptiometry body composition estimates change across the MC and differ compared with HC users. This was accomplished during a 5-week training camp involving naturally cycling athletes (n = 11) and HC users (n = 7 subdermal progestin implant, n = 4 combined monophasic oral contraceptive pill, n = 1 injection) from the National Rugby League Indigenous Women's Academy. MC phase was retrospectively confirmed via serum estradiol and progesterone concentrations and a positive ovulation test. HC users had serum estradiol and progesterone concentrations assessed at the time point of testing. Results were analyzed using general linear mixed model. There was no effect of MC phase on absolute RMR (p =.877), relative RMR (p =.957), or dual-energy X-ray absorptiometry body composition estimates (p >.05). There was no effect of HC use on absolute RMR (p =.069), relative RMR (p =.679), or fat mass estimates (p =.766), but HC users had a greater fat-free mass and lean body mass than naturally cycling athletes (p =.028). Our findings suggest that RMR and dual-energy X-ray absorptiometry body composition estimates do not significantly differ due to changes in sex hormones in a group of athletes, and measurements can be compared between MC phases or with HC usage without variations in sex hormones causing additional noise. [ABSTRACT FROM AUTHOR]

Carbohydrate (CHO) supplementation during endurance exercise can improve performance. However, it is unclear whether low glycemic index (GI) CHO leads to differential ergogenic and metabolic effects compared with a standard high GI CHO. This study investigated the ergogenic and metabolic effects of CHO supplementation with distinct GIs, namely, (a) trehalose (30 g/hr), (b) isomaltulose (30 g/hr), (c) maltodextrin (60 g/hr), and (d) placebo (water). In this double-blind, crossover, counterbalanced, placebo-controlled study, 13 male cyclists cycled a total of 100 min at varied exercise intensity (i.e., 10-min stages at 1.5, 2.0, and 2.5 W/kg; repeated three times plus two 5-min stages at 1.0 W/kg before and after the protocol), followed by a 20-min time trial on four separated occasions. Blood glucose and lactate (every 20 min), heart rate, and ratings of perceived exertion were collected throughout, and muscle biopsies were taken before and immediately after exercise. The results showed that trehalose improved time-trial performance compared with placebo (total work done 302 ± 39 vs. 287 ± 48 kJ; p =.01), with no other differences between sessions (all p ≥.07). Throughout the 100-min protocol, blood glucose was higher with maltodextrin compared with the other supplements at all time points (all p <.05). Heart rate, ratings of perceived exertion, muscle glycogen content, blood glucose, and lactate were not different between conditions when considering the 20-min time trial (all p >.05). Trehalose supplementation throughout endurance exercise improved cycling performance and appears to be an appropriate CHO source for exercise tasks up to 2 hr. No ergogenic superiority between the different types of CHO was established. [ABSTRACT FROM AUTHOR]

Purpose: To develop and evaluate a theory on the frequent observation that cyclists prefer cadences (RPMs) higher than those considered most economical at submaximal exercise intensities via modeling and simulation of its mathematical description. Methods: The theory combines the parabolic power-to-velocity (v) relationship, where v is defined by crank length, RPM-dependent ankle velocity, and gear ratio, RPM effects on the maximal lactate steady state (MLSS), and lactate-dependent carbohydrate oxidation (CHO). It was tested against recent experimental results of 12 healthy male recreational cyclists determining the v-dependent peak oxygen uptake (VO2PEAKv), MLSS (MLSSv), corresponding power output (PMLSSv), oxygen uptake at PMLSSv (VO2MLSSv), and CHOMLSSv-management at 100 versus 50 per minute, respectively. Maximum RPM (RPMMAX) attained at minimized pedal torque was measured. RPM-specific maximum sprint power output (PMAXv) was estimated at RPMs of 100 and 50, respectively. Results: Modeling identified that MLSSv and PMLSSv related to PMAXv (IPMLSSv) promote CHO and that VO2MLSSv related to VO2PEAKv inhibits CHO. It shows that cycling at higher RPM reduces IPMLSSv. It suggests that high cycling RPMs minimize differences in the reliance on CHO at MLSSv between athletes with high versus low RPMMAX. Conclusions: The present theory-guided modeling approach is exclusively based on data routinely measured in high-performance testing. It implies a higher performance reserve above IPMLSSv at higher RPM. Cyclists may prefer high cycling RPMs because they appear to minimize differences in the reliance on CHO at MLSSv between athletes with high versus low RPMMAX. [ABSTRACT FROM AUTHOR]

Bike fitting aims to optimize riders' positions to improve their performance and reduce the risk of injury. To calculate joint angles, the location of the joint centers of the lower limbs needs to be identified. However, one of the greatest difficulties is the location of the hip joint center due to the frequent occlusion of the anterior superior iliac spine markers. Therefore, the objective of this study was to validate a biomechanical model adapted to cycling (modified pelvic model, MPM), based on the traditional pelvic model (TPM) with an additional lateral technical marker placed on the iliac crests. MPM was also compared with a widely used model in cycling, trochanter model (TM). Thirty-one recreational cyclists pedaled on a roller bike while the movement was captured with a 7-camera VICON system. The position of the hip joint center and knee angle were calculated and compared with the TPM continuously (along 10 pedaling cycles) and discreetly at 90° and 180° crank positions. No significant differences were found in the position of the hip joint center or in the knee flexion/extension angle between the TPM and the MPM. However, there are differences between TPM and TM (variations between 4.1° and 6.9° in favor of the TM at 90° and 180°; P <.001). Bland–Altman graphs comparing the models show an average difference or bias close to 0° (limits of agreement [0.2 to −8.5]) between TPM and MPM in both lower limbs and a mean difference of between −4° and −7° (limits of agreement [−0.6 to −13.2]) when comparing TPM and TM. Given the results, the new cycling pelvic model has proven to be valid compared with the TPM when performing bike fitting studies, with the advantage that the occluded markers are avoided. Despite its simplicity, the TM presents measurement errors that may be relevant when making diagnoses, which makes its usefulness questionable. [ABSTRACT FROM AUTHOR]

Manipulating the amount of muscle mass engaged during exercise can noninvasively inform the contribution of central cardiovascular and peripheral vascular-oxidative functions to endurance performance. To better understand the factors contributing to exercise limitation in older and younger individuals, exercise performance was assessed during single-leg and double-leg cycling. 16 older (67 ± 5 years) and 14 younger (35 ± 5 years) individuals performed a maximal exercise using single-leg and double-leg cycling. The ratio of single-leg to double-leg cycling power (RatioPower SL/DL) was compared between age groups. The association between fitness (peak oxygen consumption, peak power output, and physical activity levels) and RatioPower SL/DL was explored. The RatioPower SL/DL was greater in older compared with younger individuals (1.14 ± 0.11 vs. 1.06 ± 0.08, p =.041). The RatioPower SL/DL was correlated with peak oxygen consumption (r =.886, p <.001), peak power output relative to body mass (r =.854, p <.001), and levels of physical activity (r =.728, p =.003) in the younger but not older subgroup. Reducing the amount of muscle mass engaged during exercise improved exercise capacity to a greater extent in older versus younger population and may reflect a greater reduction in central cardiovascular function compared with peripheral vascular-oxidative function with aging. [ABSTRACT FROM AUTHOR]

Background: Durability (ie, the ability to attenuate the decline in performance after accumulated work) has been identified as a performance determinant in elite cyclists. The aim of the present study was to compare durability in elite cyclists of various performance levels, particularly after high-intensity work, referred to as "high-intensity durability." Methods: Forty-nine (N = 49) male road cyclists were categorized as either under 23 years of age (U23) (N = 11), Pro Team (N = 13), or World Tour (N = 24). The participants' critical power (CP) was assessed during the preseason. Thereafter, the participants' maximum mean power (MMP) values were determined for efforts of different durations (from 5 s to 30 min) after different levels of accumulated work above CP (from 0 to 7.5 kJ·kg−1). Results: U23 cyclists showed a significant reduction of all relative MMP values for durations ≥1 minute after ≥5 kJ·kg−1 above CP compared with the "fresh" state (0 kJ·kg−1), whereas in Pro Team and World Tour cyclists, a significant reduction was not observed until 7.5 kJ·kg−1 above CP. In the "fresh" state, both Pro Team and particularly World Tour cyclists attained higher MMP values for efforts ≥10 minutes than U23 riders. However, more differences emerged with greater previous work levels, and indeed after 7.5 kJ·kg−1 above CP World Tour cyclists attained higher MMP values than both U23 and Pro Team cyclists for most efforts (≥30 s). Conclusion: Pro Team and particularly World Tour cyclists tolerate greater levels of accumulated work at high intensity, which might support the importance of high-intensity durability for performance. [ABSTRACT FROM AUTHOR]

Purpose: To assess (1) whether and how a higher maximal lactate steady state (MLSS) at higher cycling cadence (RPM) comes along with higher absolute and/or fractional carbohydrate combustion (CHOMLSS), respectively, and (2) whether there is an interrelation between potential RPM-dependent MLSS effects and the maximally achievable RPM (RPMMAX). Methods: Twelve healthy males performed incremental load tests to determine peak power, peak oxygen uptake, and 30-minute MLSS tests at 50 and 100 per minute, respectively, to assess RPM-dependent MLSS, corresponding power output, CHOMLSS responses, and 6-second sprints to measure RPMMAX. Results: Peak power, peak carbon dioxide production, and power output at MLSS were lower (P =.000, ω2 = 0.922; P =.044, ω2 > 0.275; and P =.016, ω2 = 0.373) at 100 per minute than at 50 per minute. With 6.0 (1.5) versus 3.8 (1.2) mmol·L−1, MLSS was higher (P =.000, ω2 = 0.771) at 100 per minute than at 50 per minute. No corresponding RPM-dependent differences were found in oxygen uptake at MLSS, carbon dioxide production at MLSS, respiratory exchange ratio at MLSS, CHOMLSS, or fraction of oxygen uptake used for CHO at MLSS, respectively. There was no correlation between the RPM-dependent difference in MLSS and RPMMAX. Conclusions: The present study extends the previous finding of a consistently higher MLSS at higher RPM by indicating (1) that at fully established MLSS conditions, respiration and CHOMLSS management do not differ significantly between 100 per minute and 50 per minute, and (2) that linear correlation models did not identify linear interdependencies between RPM-dependent MLSS conditions and RPMMAX. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to cross-validate a recently proposed equation for the prediction of maximal oxygen uptake ( V ˙ O 2 max) in cycling exercise by using the average power output normalized by the body mass from a 5-minute time trial (RPO5-min) as the independent variable. Further, the study aimed to update the predictive equation using Bayesian informative prior distributions and meta-analysis. Methods: On different days, 49 male cyclists performed an incremental graded exercise test until exhaustion and a 5-minute time trial on a stationary cycle ergometer. We compared the actual V ˙ O 2 max with the predicted value obtained from the RPO5-min, using a modified Bayesian Bland–Altman agreement analysis. In addition, this study updated the data on the linear regression between V ˙ O 2 max and RPO5-min, by incorporating information from a previous study as a Bayesian informative prior distribution or via meta-analysis. Results: On average, the predicted V ˙ O 2 max using RPO5-min underestimated the actual V ˙ O 2 max by −6.6 mL·kg–1·min–1 (95% credible interval, −8.6 to −4.7 mL·kg–1·min–1). The lower and upper 95% limits of agreement were −17.2 (−22.7 to −12.3) and 3.8 (−1.0 to 9.5) mL·kg–1·min–1, respectively. When the current study's data were analyzed using the previously published data as a Bayesian informative prior distribution, the accuracy of predicting sample means was found to be better when compared with the data combined via meta-analyses. Conclusions: The proposed equation presented systematic bias in our sample, in which the prediction underestimated the actual V ˙ O 2 max. We provide an updated equation using the previous one as the prior distribution, which could be generalized to a greater audience of cyclists. [ABSTRACT FROM AUTHOR]

This study sought to investigate the effect of cold ambient temperature on subcutaneous abdominal adipose tissue (SCAAT) lipolysis and blood flow during steady-state endurance exercise in endurance-trained cyclists. Ten males (age: 23 ± 3 years; peak oxygen consumption: 60.60 ± 4.84 ml·kg−1·min−1; body fat: 18.4% ± 3.5%) participated in baseline lactate threshold (LT) and peak oxygen consumption testing, two familiarization trials, and two experimental trials. Experimental trials consisted of cycling in COLD (3 °C; 42% relative humidity) and neutral (NEU; 19 °C; 39% relative humidity) temperatures. Exercise consisted of 25 min cycling at 70% LT and 25 min at 90% LT. In situ SCAAT lipolysis and blood flow were measured via microdialysis. Heart rate, core temperature, carbohydrate and fat oxidation, blood glucose, and blood lactate were also measured. Heart rate, core temperature, oxygen consumption, and blood lactate increased with exercise but were not different between COLD and NEU. SCAAT blood flow did not change from rest to exercise or between COLD and NEU. Interstitial glycerol increased during exercise (p <.001) with no difference between COLD and NEU. Fat oxidation increased (p <.001) at the onset of exercise and remained elevated thereafter with no difference between COLD and NEU. Carbohydrate oxidation increased with increasing exercise intensity and was greater at 70% LT in COLD compared to NEU (p =.030). No differences were observed between conditions for any other variable. Cycling exercise increased SCAAT lipolysis but not blood flow. Ambient temperature did not alter SCAAT metabolism, SCAAT blood flow, or fat oxidation in well-trained cyclists, though cold exposure increased whole-body carbohydrate oxidation at lower exercise intensities. [ABSTRACT FROM AUTHOR]

Purpose: Precooling (PreC) may only benefit performance when thermal strain experienced by an individual is sufficiently high. We explored the effect of mixed-method PreC on 20-km cycling time-trial (CTT) performance under 3 different apparent temperatures (AT). Methods: On separate days, 12 trained or highly trained male cyclists/triathletes completed six 20-km CTTs in 3 different ATs: hot-dry (35 °C AT), moderately hot-humid (40 °C AT), and hot-humid (46 °C AT). All trials were preceded by 30 minutes of mixed-method PreC or no PreC (control [CON]). Results: Faster 2.5-km-split completion times occurred in PreC compared with CON in 46 °C AT (P =.02), but not in 40 °C AT (P =.62) or 35 °C AT (P =.57). PreC did not affect rectal and body temperature during the 20-km CTT. Skin temperature was lower throughout the CTT in PreC compared with CON in 46 °C AT (P =.01), but not in 40 °C AT (P = 1.00) and 35 °C AT (P = 1.00). Heart rate had a greater rate of increase during the CTT for PreC compared with CON in 46 °C AT (P =.01), but not in 40 °C AT (P =.57) and 35 °C AT (P = 1.00). Ratings of perceived exertion (P <.001) and thermal comfort (P =.04) were lower for PreC compared with CON in 46 °C AT only, while thermal sensation was not different between PreC and CON. Conclusion: Mixed-method PreC should be applied prior to 20-km CTTs conducted in hot-humid conditions (≥46 °C AT). Alternatively, mixed-method PreC may be a priority in moderately hot-humid (∼40 °C AT) conditions but should not be in hot-dry (∼35 °C AT) conditions for 20-km CTT. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to describe the day-by-day training and racing characteristics in preparation for the Giro d'Italia of 1 world-class road cyclist who achieved a place on the podium in the final general classification of the Giro d'Italia. Methods: Day-by-day power meter training and racing data of 1 study subject (road cyclist; age 25 y; relative maximum oxygen consumption 81 mL·min−1·kg−1; relative 20-min record power output 6.6 W·kg−1) covering the 152 days leading up to the podium in the Giro d'Italia final general classification were retrospectively analyzed. Daily load, daily volume, and intensity distribution were considered. Results: During training a pattern alternating "hard days" versus "easy days" was observed, as significant amounts of medium or high intensity, or load, were not performed for more than 2 consecutive days This pattern was achieved combining high volume (>4 h) with a significant amount of medium and high intensity within the same training sessions. During training, when training load and intensity increased, the density of "easy days" augmented. In 1-week stage races and the Giro d'Italia, 3 to 8 consecutive days with significant amounts of medium and high intensity were performed. A high number of training sessions with small amounts of medium- and high-intensity volume was observed: 38 days accumulating 3 to 10 minutes at medium intensity and 29 days spending 1 to 9 minutes at high intensity. Conclusion: These data provide novel insights about the day-by-day periodization strategies leading to a top 3 in the Giro d'Italia general classification. [ABSTRACT FROM AUTHOR]

Purpose: To examine the impact of oral contraceptive (OC) phases on performance, physiological, and subjective responses to prolonged, intensive exercise when carbohydrate (CHO) stores are reduced. Methods: Ten well-trained female cyclists using monophasic OC completed 4 identical trials (>150 min) under conditions of in-trial 60-g·h−1 CHO supplementation (CHO+) or placebo (CHO−) during the sugar- (SUG) and active-pill (ACT) phases of their OC cycle. Each trial comprised two 400-kcal time trials (TT) separated by 1 hour of submaximal cycling at first ventilatory threshold. Results: Change in completion time from TT1 to TT2 was minimized in CHO+ compared with CHO− (4.06 [2.55] vs 6.08 [5.33] min; P =.019, effect size = −0.36). An interaction effect of OC and CHO was observed for time to complete TT (P =.006), mean TT power (P =.002), mean TT heart rate (P =.002), and posttrial emotional balance (P =.020) and negative emotional state (P =.033). In ACT, mean TT power and heart rate were higher in CHO+ when compared with CHO−, resulting in faster TTs in CHO+ and improved posttrial emotional well-being. When CHO was not supplemented, TT power and heart rate were higher in SUG when compared with ACT, resulting in faster TTs in SUG and improved posttrial emotional balance. Conclusion: CHO depletion during ACT negatively influenced TT performance and emotional well-being when compared with SUG. Irrespective of OC pill phase, CHO supplementation should be prioritized to sustain performance and improve postexercise recovery–stress balance. [ABSTRACT FROM AUTHOR]

Alexander Pho and Benjamin A. White respond to Nicolas Dixon's critique of mixed martial arts (MMA) through a 'companions in innocence' argument. Taking up a counterexample that Dixon is quick to dismiss, the authors argue that MMA techniques are on a par with the 'pain-leveraging' tactics used by cyclists and that pressing for a moral distinction between cycling and MMA leads to absurd conclusions about other practices. So, because cycling is morally permissible, MMA is morally permissible. This companions in innocence argument fails. But cycling can be used to develop a better, though only partial, defense of MMA. [ABSTRACT FROM AUTHOR]

Introduction: This case study aimed to describe potential changes in neuromuscular activation and synergies after an 8-day cross-country mountain-bike stage race. Methods: A peak power output test was performed 5 days before the race. Two days before the start and after 7 days of racing, the athlete performed a power-based Lamberts Submaximal Cycling Test, including surface electromyography, and completed a Daily Analysis of Life Demands of Athletes questionnaire. Neuromuscular activation, in terms of root mean square, timing (onset-offset) of muscle activation, and synergies, was obtained from electromyography recordings. Results: The athlete reported an increase in symptoms of experienced stress after the stage race on the Daily Analysis of Life Demands of Athletes questionnaire. Both biceps femoris and tibialis anterior muscles showed a reduction in normalized amplitude after the stage race. In addition, the number of synergies that was necessary to describe neuromuscular activation increased from 2 to 3. Conclusions: In this case study, the increase in synergies suggests that, after the stage race, the athlete showed a more complex muscle-recruitment pattern. This may indicate that muscle coordination can change when muscle fatigue occurs; however, further research is needed to confirm these results in a larger sample. [ABSTRACT FROM AUTHOR]

Purpose: This study aimed to investigate acute psychophysiological responses to repeated-sprint training in hypoxia (RSH) combined with whole-body cryotherapy (WBC). Method: Sixteen trained cyclists performed 3 sessions in randomized order: RSH, WBC-RSH (WBC pre-RSH), and RSH-WBC (WBC post-RSH). RSH consisted of 3 sets of 5 × 10-second sprints with 20-second recovery at a simulated altitude of 3000 m. Power output, muscle oxygenation (tissue saturation index), heart-rate variability, and recovery perception were analyzed. Sleep quality was assessed on the nights following test sessions and compared with a control night using nocturnal ActiGraphy and heart-rate variability. Results: Power output did not differ between the conditions (P =.27), while the decrease in tissue saturation index was reduced for WBC-RSH compared to RSH-WBC in the last set. In both conditions with WBC, the recovery perception was higher compared to RSH (WBC-RSH: +15.4%, and RSH-WBC: +21.9%, P <.05). The number of movements during the RSH-WBC night was significantly lower than for the control night (−18.7%, P <.01) and WBC-RSH (−14.9%, P <.05). RSH led to a higher root mean square of the successive differences of R-R intervals and high-frequency band during the first hour of sleep compared to the control night (P <.05) and RSH-WBC (P <.01). Conclusions: Inclusion of WBC in an RSH session did not modify the power output but could improve prolonged performance in hypoxia by maintaining muscle oxygenation. A single RSH session did not deteriorate sleep quality. WBC, particularly when performed after RSH, positively influenced recovery perception and sleep. [ABSTRACT FROM AUTHOR]

Most people with intellectual disabilities have comorbid health conditions, which will impact optimization of sporting performance. Classification is used in Paralympic events to ensure that those with similar levels of functional ability compete fairly against each other. An evidence-based approach needs to be developed for athletes with intellectual disabilities to be classified in relation to their overall functional capacity into competition groups of similar ability. This research builds on previous work using the taxonomy of The International Classification of Functioning, Disability and Health (ICF) to group athletes with intellectual disabilities into comparable competition groups as an approach to Paralympic classification. Three groups of athletes—Virtus, Special Olympics, and Down syndrome—are compared using the ICF questionnaire indicating functional health status in relation to sporting performance. The questionnaire was found to discriminate between athletes with Down syndrome and other athletes, and an approach to using a cutoff score to develop competition classes is explored. [ABSTRACT FROM AUTHOR]

This study assessed the effect of combined jump training and collagen supplementation on bone mineral density (BMD) in elite road-race cyclists. In this open-label, randomized study with two parallel groups, 36 young (21 ± 3 years) male (n = 8) and female (n = 28) elite road-race cyclists were allocated to either an intervention (INT: n = 18) or a no-treatment control (CON: n = 18) group. The 18-week intervention period, conducted during the off-season, comprised five 5-min bouts of jumping exercise per week, with each bout preceded by the ingestion of 15 g hydrolyzed collagen. Before and after the intervention, BMD of various skeletal sites and trabecular bone score of the lumbar spine were assessed by dual-energy X-ray absorptiometry, along with serum bone turnover markers procollagen Type I N propeptide and carboxy-terminal cross-linking telopeptide of Type I collagen. BMD of the femoral neck decreased in CON (from 0.789 ± 0.104 to 0.774 ± 0.095 g/cm2), while being preserved in INT (from 0.803 ± 0.058 to 0.809 ± 0.066 g/cm2; Time × Treatment, p <.01). No differences between treatments were observed for changes in BMD at the total hip, lumbar spine, and whole body (Time × Treatment, p >.05 for all). Trabecular bone score increased from 1.38 ± 0.08 to 1.40 ± 0.09 in CON and from 1.46 ± 0.08 to 1.47 ± 0.08 in INT, respectively (time effect: p <.01), with no differences between treatments (Time × Treatment: p =.33). Serum procollagen Type I N propeptide concentrations decreased to a similar extent in CON (83.6 ± 24.8 to 71.4 ± 23.1 ng/ml) and INT (82.8 ± 30.7 to 66.3 ± 30.6; time effect, p <.001; Time × Treatment, p =.22). Serum carboxy-terminal cross-linking telopeptide of Type I collagen concentrations did not change over time, with no differences between treatments (time effect, p =.08; Time × Treatment, p =.58). In conclusion, frequent short bouts of jumping exercise combined with collagen supplementation beneficially affects femoral neck BMD in elite road-race cyclists. [ABSTRACT FROM AUTHOR]

Guarana (GUA) seed extract, containing caffeine (CAF) and additional bioactive compounds, may positively affect mental performance, but evidence regarding exercise is limited. This investigation assessed acute GUA ingestion compared with CAF on endurance performance. Eleven endurance-trained noncyclists and cyclists (V ˙ O 2 peak = 49.7 ± 5.9, 60.4 ± 4.6 ml·kg·min−1) completed a double-blind, crossover experiment after ingesting (a) 100 mg CAF, (b) 500 mg GUA (containing 130 mg CAF), or (c) placebo (P) prior to 60-min fixed cycling workload (FIX) + 15-min time trial. Oxygen uptake, heart rate, respiratory exchange ratio, blood glucose, and lactate were not different (p ≥.052) during FIX. A significant interaction (p =.042) for perceived exertion was observed at 50-min FIX with lower rating (p =.023) for GUA versus CAF but not compared with P. Work accumulated over 15-min time trial was greater (p =.038) for GUA versus P due to higher early (1–11 min) work outputs. Work performance favored (effect size = 0.18; 95% confidence interval [0.003, 0.355], p =.046) GUA (241.4 ± 39.9 kJ) versus P (232.1 ± 46.6 kJ), but CAF (232.3 ± 43.9) was not different from GUA (effect size = 0.19; 95% confidence interval [−0.022, 0.410], p =.079) or P. Postexercise strength loss was not attenuated with GUA (−5.6 ± 8.5%) or CAF (−8.3 ± 9.4%) versus P (−10.3 ± 5.1%). Acute GUA ingestion improved work performance relative to P, but effects were trivial to small and unrelated to altered substrate oxidation or muscular strength. Ergogenicity may involve central mechanisms reducing perceived effort with GUA (containing 130 mg caffeine). Due to issues related to identical matching of dosage, whether GUA confers additional benefits beyond its CAF content cannot be determined at present. [ABSTRACT FROM AUTHOR]

The present randomized study investigated the effect of acute supplementation of 800 mg/kg of ketone monoester ingestion (KE) or placebo (PL) and 210 mg/kg of NaHCO3 co-ingestion on cycling performance of WorldTour cyclists during a road cycling stage simulation. Twenty-eight cyclists participated in the study (27.46 ± 4.32 years; 1.80 ± 0.06 m; 69.74 ± 6.36 kg). Performance, physiological, biochemical, and metabolism outcomes, gut discomfort, and effort perceived were assessed during a road cycling simulation composed of an 8-min time-trial (TT) performance + 30-s TT + 4.5 hr of outdoor cycling + a second 8-min TT + a second 30-s TT. Greater absolute and relative mean power during the first 8-min TT (F = 5.067, p =.033, η p 2 =.163 , F = 5.339, p =.029, η p 2 =.170 , respectively) was observed after KE than after PL (KE: 389 ± 34, PL: 378 ± 44 W, p =.002, d = 0.294 and KE: 5.60 ± 0.42, PL: 5.41 ± 0.44 W/kg, p =.001, d = 0.442). Additionally, greater concentration of β-hydroxybutyrate blood concentration (F = 42.195, p <.001, η p 2 =.619) was observed after KE than after PL during the first steps of the stage (e.g., after warm-up KE: 1.223 ± 0.642, PL: 0.044 ± 0.058 mM, p <.001, d = 2.589), although the concentrations returned to near baseline after 4.5 hr of outdoor cycling. Moreover, higher values of anion gap were observed (F = 2.333, p =.026, η p 2 =.080) after KE than after PL ingestion, after the warm-up and after the first 8-min and 30-s TT. Additionally, lower concentrations of HCO 3 − were reported in the KE condition after warm-up and after the first 8-min and 30-s TT. During the initial phase of the stage simulation, acute supplementation with KE + NaHCO3 co-ingestion enhanced 8-min TT cycling performance (3.1%) in WorldTour cyclists with a concomitant hyperketonaemia. [ABSTRACT FROM AUTHOR]

Despite a strong body of evidence supporting benefits of exercise to reduce severity of motor symptoms of Parkinson's Disease (PD) over time, research on the immediate impact of exercise as an adjunctive therapy for nonpharmacologic management of motor symptoms and mobility performance in people with PD is limited. The purpose of this study was to examine immediate effects of a single bout of high-cadence cycling on motor symptoms of PD and performance-based outcomes. Twenty individuals with idiopathic PD participated in a pretest/posttest study investigating immediate impacts of a single high-cadence cycling session on performance-based outcomes across multiple domains of motor function, mobility, and balance. Outcomes were analyzed based on time since last dose of levodopa/carbidopa medication. Immediate improvements were observed in motor symptoms of PD with significant improvements in performance across multiple balance systems, dynamic gait, and upper-extremity coordination following a cycling intervention. [ABSTRACT FROM AUTHOR]

Athletes must transfer their performance when changing equipment due to innovative developments in sports technology. This kind of transfer has received only moderate attention. The aim of this study was to examine whether a mechanical change in sports equipment disturbs an athlete's performance and affects biomechanical and neurophysiological parameters. Therefore, an experiment was conducted in which 36 participants in three groups pedaled at 70 rounds per minute on a cycling ergometer with a circular and a noncircular (NC) chainring. The dependent variables were the total variability of the cadence, torque effectiveness, and muscle cocontraction (electromyographic cocontraction) of four antagonistic acting muscle pairs. Data were recorded during an acquisition phase, a transfer phase, and a retention phase. The results revealed that practice on a circular chainring induces a positive transfer on the NC chainring for total variability without a proactive interference effect. Torque effectiveness did not change within or between groups during the acquisition, transfer, and retention phases. Torque effectiveness and electromyographic cocontraction were not affected when the chainrings were altered from Day 1 to Day 2. During the retention phase, electromyographic cocontraction was higher when using the NC chainring, but the difference was small in absolute terms. The results regarding transfer and proactive interference seem to be strongly dependent on the movement task and the change in sports equipment. Transfer from the circular to NC chainring indicates refined neuromuscular control and improved movement coordination. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the effect of cycling-based repeated-sprint training in hypoxia versus in normoxia on single overground running sprint performance and associated force–velocity (F–V) profile in world-class female rugby sevens players. Methods: Eighteen world-class female rugby sevens players were randomly assigned to repeated-sprint cycling training in normobaric hypoxia (n = 9) or normoxia (n = 9) groups. Training consisted of 4 sessions of repeated-sprint cycling training in normobaric hypoxia or in normoxia (4 × 5 × 5-s cycle sprints—25-s intersprint recovery performed in simulated altitude of ∼5000 m or in normoxia with 3-min interset rest in normoxia for both groups) in addition to rugby sevens training and strength and conditioning sessions within a 9-day intervention period before an international competition. Before and 1 day after the intervention, single 50-m overground running "all-out" sprint performance and associated F–V-related mechanical output were assessed. Results: No interaction (group × time; all P >.088), time effect (before vs 1 d after; all P >.296), or group effect (repeated-sprint cycling training in normobaric hypoxia vs in normoxia; all P >.325) was detected for 50-m overground running sprint performance and any derived F–V profiling variables. Conclusions: Four sessions of repeated-sprint training either in hypoxia or in normoxia performed over 9 days had no influence on single 50-m overground running sprint performance and associated F–V profile. In world-class female rugby sevens players, the intervention (training camp before an international competition) might have been too short to induce measurable changes. It is also plausible that implementing a similar program in players with likely different F–V profile may result in negligible mechanical effect. [ABSTRACT FROM AUTHOR]

The purpose of this study was to investigate the influence of mouth rinsing and ingesting unpleasant salty or bitter solutions on cycling sprint performance and knee extensor force characteristics. Eleven male and one female trained cyclists (age: 34 ± 9 years, maximal oxygen uptake 56.9 ± 3.9 ml·kg−1·min−1) completed a ramp test and familiarization followed by four experimental trials. In each trial, participants completed an all-out 30-s cycling sprint with knee extensor maximal voluntary contractions before and immediately after the sprint. In a randomized, counterbalanced, cross-over order, the four main trials were: a no solution control condition, water, salty (5.8%), or bitter (2 mM quinine) solutions that were mouth rinsed (10 s) and ingested immediately before the cycling sprint. There were no significant differences between conditions in mean power (mean ± SD, no solution: 822 ± 115 W, water: 818 ± 108 W, salt: 832 ± 111 W, bitter: 818 ± 105 W); peak power (no solution: 1,184 ± 205 W, water: 1,177 ± 207 W, salt: 1,195 ± 210 W, bitter: 1,184 ± 209 W); or fatigue index (no solution: 51.5% ± 5.7%, water: 50.8% ± 7.0%, salt: 51.1% ± 5.9%, bitter: 51.2% ± 7.1%) during the sprint. Maximal force and impulse declined postexercise; however, there were no significant differences between conditions in knee extensor force characteristics. The present data do not support the use of unpleasant salty or bitter solutions as an ergogenic aid to improve sprint exercise performance. [ABSTRACT FROM AUTHOR]

Purpose: To compare the effects of graded hypoxia during exhaustive intermittent cycling on subsequent rapid and maximal torque-production capacity. Methods: Fifteen well-trained cyclists repeated intermittent cycling bouts (15 s at 30% of anaerobic power reserve; rest = 45 s) until exhaustion at sea level (FiO2 ∼0.21/end-exercise arterial oxygen saturation ∼96%), moderate hypoxia (FiO2 ∼0.16/∼90%), and severe hypoxia (FiO2 ∼0.12/∼79%). Rapid (rate of torque development [RTD]) and maximal isometric torque-production capacities of the knee extensors were assessed at baseline (visit 1) and exhaustion (visits 2–4). Results: Exercise capacity decreased with hypoxia severity (39 [30], 22 [13], and 13 [6] cycle efforts in sea level, moderate hypoxia, and severe hypoxia, respectively; P =.002). Changes in maximal-voluntary-contraction torque between baseline and postexercise in all conditions were not statistically significant (pooled values: −2.6% [5.7%]; P =.162). Peak RTD measured postexercise was reduced below baseline in all conditions (–21.5% [5.1%]; P ≤.015). Compared with baseline, absolute RTD values were lower at 0- to 30-millisecond (–35.1% [5.3%], P ≤.020), 0- to 50-millisecond (–40.0% [3.9%], P ≤.002), 0- to 100-millisecond (–30.7% [3.7%], P ≤.001), and 0- to 200-millisecond (–18.1% [2.4%], P ≤.004) time intervals in all conditions. Conclusions: Exhaustive intermittent cycling induces substantial yet comparable impairments in RTD of knee extensors between normoxia and moderate to severe hypoxia. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to describe individual training characteristics, racing strategies, and periodization in preparation for the Tour de France in 2 world-class road cyclists finishing in the top 5 of the general classification. Methods: Week‐by‐week power meter training and racing data of 2 (A and B) road cyclists (age: 29 and 23 y; maximum oxygen consumption: 83 and 81 mL·min−1·kg−1; and relative 20‐min record power output: 6.9 and 6.5 W·kg−1) in the preparation phase (December–July/August) leading up to the Tour de France were retrospectively analyzed. Weekly volume and intensity distribution in power zones were considered. Results: Cyclists A and B completed 46 and 19 races, 22.5 (6.3) and 18.2 (5.1) h·wk−1, with a pyramidal intensity distribution of 81.0%–13.3%–5.7%, and 88.8%–7.9%–3.3% in zone 1–zone 2–zone 3. Cyclist B spent 14 days at altitude. Increased high-intensity volume and polarization index occurred during race weeks. During periods without racing, training intensity progressively increased. Strength training was performed during November and December but not during the following months. During tapering, total exercise volume and time at high intensity decreased. Conclusion: These data provide novel insights into the periodization of world-class road cyclists in advance of a top 5 placing in the Tour de France general classification. [ABSTRACT FROM AUTHOR]

Purpose: Laboratory-based indicators are commonly used for performance assessment in young cyclists. However, evidence supporting the use of these indicators mostly comes from cross-sectional research, and their validity as predictors of potential future performance remains unclear. We aimed to assess the role of laboratory variables for predicting transition from U23 (under 23 y) to professional category in young cyclists. Methods: Sixty-five U23 male road cyclists (19.6 [1.5] y) were studied. Endurance (maximal graded test and simulated 8-min time trial [TT]), muscle strength/power (squat, lunge, and hip thrust), and body composition (assessed with dual-energy X-ray absorptiometry) indicators were determined. Participants were subsequently followed and categorized attending to whether they had transitioned ("Pro") or not ("Non-Pro") to the professional category during the study period. Results: The median follow-up period was 3 years. Pro cyclists (n = 16) showed significantly higher values than Non-Pro riders (n = 49) for ventilatory thresholds, peak power output, peak oxygen uptake, and TT performance (all P <.05, effect size > 0.69) and lower levels of fat mass and bone mineral content/density (P <.05, effect size > 0.63). However, no significant differences were found for muscle strength/power indicators (P >.05, effect size < 49). The most accurate individual predictor was TT performance (overall predictive value = 76% for a cutoff value of 5.6 W·kg−1). However, some variables that did not reach statistical significance in univariate analyses contributed significantly to a multivariate model (R2 =.79, overall predictive value = 94%). Conclusions: Although different "classic" laboratory-based endurance indicators can predict the potential of reaching the professional category in U23 cyclists, a practical indicator such as 8-minute TT performance showed the highest prediction accuracy. [ABSTRACT FROM AUTHOR]

Purpose: The record power profile (RPP) has gained popularity as a method of monitoring endurance cycling performance. However, the expected variation of cyclists' performance between seasons remains unknown. We aimed to assess the between-seasons variability of peak performance (assessed through the RPP) in male professional cyclists. Methods: The study followed a longitudinal observational design. Sixty-one male professional cyclists (age 26 [5] y) with power output data from both training sessions and competitions were analyzed for a median of 4 consecutive seasons (range 2–12). The highest mean maximum power values attained for different durations (from 10 s to 30 min), as well as the resulting critical power, were determined for each season. Within-cyclist variability between seasons was assessed, and the upper threshold of expected changes (ie, twice the normal coefficient of variation) was determined. Results: All mean maximum power values showed an overall high agreement and low variability between seasons (intraclass correlation coefficient [ICC] =.76–.88 and coefficient of variation [CV] = 3.2%–5.9%), with the lowest variability observed for long efforts (>1 min). Critical power showed an ICC and CV of.79 (95% CI,.70–.85) and 3.3% (95% CI, 3.0%–3.7%), respectively. Upper thresholds of expected variation were <12% for short efforts (≤1 min) and <8% for long efforts. Conclusions: "Real-world" peak performance assessed through the RPP shows a low variability between seasons in male professional cyclists—especially for long efforts—with expected variation being around 6% and 3% for short (≤1 min) and long efforts, respectively, and with changes >12% and >8%, respectively, being infrequent for these effort durations. [ABSTRACT FROM AUTHOR]

Objectives: Repeated-sprint training in hypoxia (RSH) is an effective way of improving physical performance compared with similar training in normoxia. RSH efficiency relies on hypoxia severity, but also on the oxidative–glycolytic balance determined by both sprint duration and exercise-to-rest ratio. This study investigated the effect of 2 types of RSH sessions during a classic altitude camp in world-class female rugby sevens players. Methods: Sixteen players performed 5 RSH sessions on a cycle ergometer (simulated altitude: 3000 m above sea level [asl]) during a 3-week natural altitude camp (1850 m asl). Players were assigned to 2 different protocols with either a high (RSH1:3, sprint duration: 8–10 s; exercise-to-rest ratios: 1:2–1:3; n = 7) or a low exercise-to-rest ratio (RSH1:5, sprint duration: 5–15 s; exercise-to-rest ratios: 1:2–1:5; n = 9). Repeated-sprint performances (maximal and mean power outputs [PPOmax, and PPOmean]) were measured before and after the intervention, along with physiological responses. Results: PPOmax (962 [100] to 1020 [143] W, P =.008, Cohen d = 0.47) and PPOmean (733 [71] to 773 [91] W, P =.008, d = 0.50) increased from before to after. A significant interaction effect (P =.048, d = 0.50) was observed for PPOmean, with a larger increase observed in RSH1:3 (P =.003). No interaction effects were observed (P >.05) for the other variables. Conclusion: A classic altitude camp with 5 RSH sessions superimposed on rugby-sevens-specific training led to an improved repeated-sprint performance, suggesting that RSH effects are not blunted by prolonged hypoxic exposure. Interestingly, using a higher exercise-to-rest ratio during RSH appears to be more effective than when applying a lower exercise-to-rest ratio. [ABSTRACT FROM AUTHOR]

Purpose: To explore the perspectives of people with Parkinson's disease (PD) and exercise providers regarding facilitating factors, barriers, needs, and demands relating to physical exercise for people with PD. Materials and Methods: Focus group discussions or telephone interviews of 30 people with PD (with or without an active sports history) and 13 providers were conducted and analyzed using structuring content analysis. Results: Factors facilitating participation in physical exercise included motivation-enhancing elements (enjoyment, group training environment) and providers with sufficient qualifications in PD-specific training demands. Identified barriers were lack of motivation, physical limitations, poor service accessibility, and inadequate matching of intervention groups based on capability or age. Providers found it difficult to design and conduct group trainings for people with PD with varying physical limitations. Having an active sports history before PD-onset was described as generally beneficial, though a competitive mindset could lead to frustration. People with PD reported needing their physicians to provide better education regarding physical exercise. Conclusion: Enjoyment of physical exercise is a key aspect of maintaining physical activity engagement, which should be considered more in research and clinical practice. Developing qualifications for providers could help to broaden and enhance the dissemination of PD-specific exercise approaches. Physicians should be trained to encourage physical exercise. Implications for rehabilitation: Physicians should highlight the benefits and be knowledgeable regarding the availability of physical exercise interventions for people with PD. Additional physical exercise providers should become qualified to work with people with PD. The joyfulness of physical exercise interventions is a key aspect of maintaining physical activity engagement for people with PD. [ABSTRACT FROM AUTHOR]

One of the longest-standing federal programs promoting Active School Transportation (AST) is the Safe Routes to School (SRTS) program. In Michigan, this program is funded by the Michigan Department of Transportation and administered by the Michigan Fitness Foundation. This paper assesses the various perceptions affecting AST. First, we look at the SRTS program in Michigan, assessing the differences in perceptions of parents and students regarding walking and biking to/from school. Second, we look at the difference in perceptions between parents living in rural and urban areas regarding the preferred mode of transport to school and the perceived challenges to using active transportation to and from school. Lastly, we look at what other built environment characteristics are associated with the use and perceptions on AST. Using primary data and statistical analyses such as Chi-Squared tests, linear and logistic regressions, we found various associations with AST and discuss the potential policy implications to understand and address the perceived barriers to using it. [ABSTRACT FROM AUTHOR]

This study compared the impact of two polarized training programs (POL) on aerobic capacity in well-trained (based on maximal oxygen uptake and training experience) female cyclists. Each 8-week POL program consisted of sprint interval training (SIT) consisting of 8–12 repetitions, each lasting 30 seconds at maximal intensity, high-intensity interval training (HIIT) consisting of 4–6 repetitions, each lasting 4 minutes at an intensity of 90–100% maximal aerobic power, and low-intensity endurance training (LIT) lasting 150–180 minutes with intensity at the first ventilatory threshold. Training sessions were organized into 4-day microcycles (1st day—SIT, 2nd day—HIIT, 3rd day—LIT, and 4th day—active rest), that were repeated throughout the experiment. In the first POL program, exercise repetitions during SIT and HIIT training were performed with freely chosen cadence above 80 RPM (POLFC group, n = 12), while in the second POL program with low cadence 50–70 RPM (POLLC group, n = 12). Immediately before and after the 8-week POL intervention, participants performed an incremental test to measure maximal aerobic power (Pmax), power achieved at the second ventilatory threshold (VT2), maximal oxygen uptake (VO2max), maximal pulmonary ventilation (VEmax), and gross efficiency (GE). Moreover, participants performed VO2max verification test. Analysis of variance showed a repeated measures effect for Pmax (F = 21.62; η2 = 0.5; p = 0.00), VO2max (F = 39.39; η2 = 0.64; p = 0.00) and VEmax (F = 5.99; η2 = 0.21; p = 0.02). A repeated measures x group mixed effect was demonstrated for Pmax (F = 4.99; η2 = 0.18; p = 0.03) and VO2max (F = 6.67; η2 = 0.23; p = 0.02). Post-hoc Scheffe analysis showed that increase in Pmax were statistically significant only in POLLC group. The Friedman test showed that VT2 differed between repeated measures only in the POLLC group (χ2 = 11; p = 0.001; W = 0.917). In conclusion, it was found that POL program where SIT and HIIT were performed at low cadence was more effective in improving aerobic capacity in well-trained female cyclists, than POL with SIT and HIIT performed at freely chosen cadence. This finding is a practical application for athletes and coaches in cycling, to consider not only the intensity and duration but also the cadence used during various interval training sessions. [ABSTRACT FROM AUTHOR]

The "storage‐oxidation" cycle is an energy‐efficient process for removing low‐concentration volatile organic compounds (VOCs). However, due to the weak interaction between BTX compounds (benzene, toluene, and xylene) and commonly used adsorbent materials, how to prevent the BTX escape prior to oxidation remains a challenge. In this work, a comprehensive study on the critical factors influencing on the "storage‐oxidation" cycling removal of BTX are investigated. The study elucidated the relationship between different zeolites and their capacity for storing BTX. It was found that the adsorption of BTX onto various zeolites is greatly impacted by the pore size of the zeolite and the volatility of BTX. Particularly, toluene and/or m‐xylene could be preferential adsorbed by Cu2+ located on the ion‐exchange sites, forming strong bonding interactions that facilitating the in‐situ thermal regeneration. Furthermore, the experimental results suggest that a synergy between Cu2+ and CuO could accelerate the catalytic oxidation of BTX. These findings offer valuable insights for designing bifunctional catalysts for the "storage‐oxidation" cycling removal of BTX. [ABSTRACT FROM AUTHOR]

The ‘cycling hour‐record’ is one of the most prestigious events in cycling. However, little detailed analysis of such attempts is available. In preparation for a successful cycling hour‐record attempt, an elite cyclist performed a full‐hour simulation to provide insights into performance, physiological, aerodynamic and biomechanical limitations that could be identified in the preparation for a subsequent official attempt. Performance (speed, lap time, power and cadence), physiological (heart rate and estimated body temperature), aerodynamic (CDA, helmet angle, rotation and rock) and biomechanical (helmet, thigh and foot position changes) measurements were made throughout the attempt, in which an even‐pacing strategy was employed where the point of task failure was defined as the lap which the rider could no longer perform at the targeted lap split (16.6 s) or quicker. The cyclist did not achieve the target distance (54,000 m) during the simulation. The final distance achieved for the hour was 53,250 m. Task failure occurred at 38 min and 33 s (lap 139/34,750 m) into the simulation. Notably, there was a decrease in power output, accompanied with an increase in the estimated body temperature, changes in pedalling kinematics and an increase in aerodynamic drag. The reduction in performance (leading to task failure) during a cycling hour record simulation is underpinned by a decrease in power output as well as an increase in aerodynamic drag due to biomechanical changes in the cycling technique. [ABSTRACT FROM AUTHOR]

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