Acute effects of fatigue on internal and external load variables determining cyclists' power profile.

The aim of the present study was to determine whether fatigue affects internal and external load variables determining power profile in cyclists. Ten cyclists performed outdoor power profile tests (lasting 1-, 5 and 20-min) on two consecutive days, subject either to a fatigued condition or not. Fatigue was induced by undertaking an effort (10-min at 95% of average power output obtained in a 20-min effort followed by 1-min maximum effort) until the power output decreased by 20% compared to the 1-min power output. Fatigued condition decreased power output (p < 0.05, 1-min: 9.0 ± 3.8%; 5-min: 5.9 ± 2.5%; 20-min: 4.1 ± 1.9%) and cadence in all test durations, without differences in torque. Lactate decreased in longer efforts when a fatigue protocol had previously been conducted (e.g., 20-min: 8.6 ± 3.0 vs. 10.9 ± 2.7, p < 0.05). Regression models (r2 ≥ 0.95, p < 0.001) indicated that a lower variation in load variables of 20-min in fatigued condition compared with the non-fatigued state resulted in a lower decrease in critical power after the fatigue protocol. The results suggest that fatigued condition on power was more evident in shorter efforts and seemed to rely more on a decrease in cadence than on torque.

Influence of Torque and Cadence on Power Output Production in Cyclists.

PURPOSE: No information is available on the torque/cadence relationship in road cyclists. We aimed to establish whether this relationship differs between cyclists of different performance levels or team roles. METHODS: Mean maximal power (MMP) output data from 177 riders were obtained from 2012 to 2021 from training and competitions. Cyclists were categorized according to their performance level (world-tour [WT, n = 68], procontinental [PC, n = 63], or under 23 [U23, n = 46]) and team role (time trialists [n = 12], all-rounders [n = 94], climbers [n = 64], or team leaders [n = 7]). RESULTS: A significant interaction effect was found for absolute and relative MMP (P < .001), with higher values in PC than WT for short (5-60 s) efforts and the opposite trend for longer durations. MMP was also greater in PC than in U23 for short efforts (30-60 s), with WT and PC attaining higher MMP than U23 for longer bouts (5-60 min). A significant interaction effect was found for cadence (P = .007, but with no post hoc differences) and absolute (P = .010) and relative torque (P = .002), with PC and WT showing significantly higher torque (all P < .05) than U23 for 5- to 60-minute efforts, yet with no differences between the former 2 performance levels. No interaction effect between team roles was found for cadence (P = .185) or relative torque (P = .559), but a significant interaction effect was found for absolute torque (P < .001), with all-rounders attaining significantly higher values than climbers for 5-second to 5-minute efforts. CONCLUSIONS: Differences in MMP between cycling performance levels and rider types are dependent on torque rather than cadence, which might support the role of torque development in performance.

Power Road-Derived Physical Performance Parameters in Junior, Under-23, and Professional Road Cycling Climbers.

PURPOSE: To investigate the relationship of field-derived power and physical performance parameters with competition success in road cycling climbing specialists of age-related categories and to explore cross-sectional differences between high-ranked (HIGHR) climbing specialists of each category. METHODS: Fifty-three male climbers participated in this study (junior [JUN], n = 15; under 23 [U23], n = 21; professional [PRO], n = 17). Training and racing data collected during the 2016-19 competitive seasons were retrospectively analyzed for record power outputs (RPOs) and RPOs after prior accumulated work. RESULTS: In JUN, body mass, absolute RPOs, and relative RPOs were higher in HIGHR compared with low ranked (d = 0.97-2.20, large; P = .097-.001); in U23 and PRO, the percentage decrease in RPOs after 20, 30, 40, and 50 kJ·kg-1 was less in HIGHR compared with low ranked (d = 0.77-1.74, moderate-large; P = .096-.004). JUN HIGHR presented lower absolute and relative RPO-20 min (ηp2=.34-.38, large; P = .099-.001) and higher percentage decrease in RPOs after prior accumulated work compared with U23 and PRO HIGHR (ηp2=.28-.68, large; P = .060-.001); percentage decrease in RPOs after prior accumulated work was the only parameter differentiating U23 and PRO HIGHR, with PRO declining less in relative RPO-1 min, RPO-5 min, and RPO-20 min after 20 to 50 kJ·kg-1 (ηp2=.28-.68, large; P = .090-.001). CONCLUSIONS: Superior absolute and relative RPOs characterize HIGHR JUN climbing specialists. Superior fatigue resistance differentiates HIGHR U23 and PRO climbers compared with low ranked, as well as PRO versus U23 climbers.

Validity and Reliability of Two Near-infrared Spectroscopy Devices to Measure Resting Hemoglobin in Elite Cyclists.

A new method to monitor internal training load from muscle oxygen saturation using near-infrared spectroscopy could be of practical application for research and training purposes. This technology has been validated in different scientific fields, including sports science, and Humon Hex and Moxy are two leading brands. However, its relationship with hemoglobin has not been studied. Forty-eight professional cyclists, 19 men and 29 women, underwent a blood test to measure hemoglobin in the early morning. Immediately afterwards, hemoglobin and muscle oxygenation were monitored at rest by Moxy and Humon Hex on their right quadriceps (where the skinfold was measured). Venous blood hemoglobin was higher than the measurement for both devices (p<0.001). Both hemoglobin (p<0.001) and muscle oxygen saturation measurements (p<0.05) were higher in Humon Hex than for Moxy, and there was a reasonable reproducibility (ICC=0.35 for hemoglobin and 0.26 for muscle oxygen saturation). Skinfold had an inverse relationship with hemoglobin measurement (r=-0.85 p<0.001 for Humon Hex and r=-0.75 p<0.001 for Moxy). These findings suggest that resting hemoglobin data provided by these devices are not coincident with those of blood sample, and skinfold has an inverse relationship with blood hemoglobin measurement.

Effect of 10 km run on lower limb skin temperature and thermal response after a cold-stress test over the following 24 h.

Skin temperature assessment has received much attention as a possible measurement of physiological response against stress produced by exercise and research studies usually measure skin temperature 24 or 48 h after exercise. Scientific evidence about skin temperature evolution during the 24-h period immediately after exercising is, however, scarce. The aim was to assess the effect of a 10 km run at moderate intensity on baseline skin temperature and thermal response after a cold stress test during that 24 h period. Fourteen participants were measured before, immediately after, and at 2, 5, 9 and 24 h after a 10 km run at a perceived exertion rate of 11 points (max 20 points). Fourteen control participants who undertook no exercise were also measured during that day. The measurements included muscle pain and fatigue perception, reactive oxygen species, heart rate variability, skin temperature of the lower limbs, and skin temperature after cold stress test. Exercise resulted in a skin temperature increase (e.g., 0.5-1.3 °C of posterior leg 9 h after exercise) and this effect continued in some regions (0.4-0.9 °C of posterior leg) over that 24 h period. However, the thermal response to the cold stress test remained the same (p > 0.05). In conclusion, 10 km aerobic running exercise results in a skin temperature increase, peaking at between 5 and 9 h after exercise, but does not alter the thermal response to a cold stress test. This study provides a sound basis for post-exercise skin temperature response that can be used as a setting-off point for comparisons with future studies that analyze greater muscle damage.

The Record Power Profile of Male Professional Cyclists: Fatigue Matters.

PURPOSE: The present study aimed to determine the influence of fatigue on the record power profile of professional male cyclists. We also assessed whether fatigue could differently affect cyclists of 2 competition categories. METHODS: We analyzed the record power profile in 112 professional cyclists (n = 46 and n = 66 in the ProTeam [PT] and WorldTour [WT] category, respectively; age 29 [6] y, 8 [5] y experience in the professional category) during 2013-2021 (8 [5] seasons/cyclist). We analyzed their mean maximal power (MMP) values for efforts lasting 10 seconds to 120 minutes with no fatigue (after 0 kJ·kg-1) and with increasing levels of fatigue (after 15, 25, 35, and 45 kJ·kg-1). RESULTS: A significant (P < .001) and progressive deterioration of all MMP values was observed from the lowest levels of fatigue assessed (ie, -1.6% to -3.0% decline after 15 kJ·kg-1, and -6.0% to -9.7% after 45 kJ·kg-1). Compared with WT, PT cyclists showed a greater decay of MMP values under fatigue conditions (P < .001), and these differences increased with accumulating levels of fatigue (decay of -1.8 to -2.9% [WT] with reference to 0 kJ·kg-1 vs -1.1% to -4.4% [PT] after 15 kJ·kg-1 and of -4.7% to -8.8% [WT] vs -7.6% to -11.6% [PT] after 45 kJ·kg-1). No consistent differences were found between WT and PT cyclists in MMP values assessed in nonfatigue conditions (after 0 kJ·kg-1), but WT cyclists attained significantly higher MMP values with accumulating levels of fatigue, particularly for long-duration efforts (≥5 min). CONCLUSIONS: Our findings highlight the importance of considering fatigue when assessing the record power profile of endurance athletes and support the ability to attenuate fatigue-induced decline in MMP values as a determinant of endurance performance.

The Record Power Profile of Male Professional Cyclists: Normative Values Obtained From a Large Database.

PURPOSE: To present normative data for the record power profile of male professional cyclists attending to team categories and riding typologies. METHODS: Power output data registered from 4 professional teams during 8 years (N = 144 cyclists, 129,262 files, and 1062 total seasons [7 (5) per cyclist] corresponding to both training and competition sessions) were analyzed. Cyclists were categorized as ProTeam (n = 46) or WorldTour (n = 98) and as all-rounders (n = 65), time trialists (n = 11), climbers (n = 50), sprinters (n = 11), or general classification contenders (n = 7). The record power profile was computed as the highest maximum mean power (MMP) value attained for different durations (1 s to 240 min) in both relative (W·kg-1) and absolute units (W). RESULTS: Significant differences between ProTeam and WorldTour were found for both relative (P = .002) and absolute MMP values (P = .006), with WT showing lower relative, but not absolute, MMP values at shorter durations (30-60 s). However, higher relative and absolute MMP values were recorded for very short- (1 s) and long-duration efforts (60 and 240 min for relative MMP values and ≥5 min for absolute ones). Differences were also found regarding cyclists' typologies for both relative and absolute MMP values (P < .001 for both), with sprinters presenting the highest relative and absolute MMP values for short-duration efforts (5-30 s) and general classification contenders presenting the highest relative MMP values for longer efforts (1-240 min). CONCLUSIONS: The present results--obtained from the largest cohort of professional cyclists assessed to date-could be used to assess cyclists' capabilities and indicate that the record power profile can differ between cyclists' categories and typologies.

Altitude and Endurance Performance in Altitude Natives versus Lowlanders: Insights from Professional Cycling.

INTRODUCTION: Acute altitude exposure influences exercise performance, although most research, especially regarding altitude natives, comes from laboratory data in nonathletes. PURPOSE: We analyzed the influence of altitude on real-world cycling performance in top-level professional cyclists attending to whether they were altitude natives or not. METHODS: Thirty-three male cyclists (29 ± 5 yr) were studied and were classified as lowlanders (n = 19) or altitude natives (n = 14) attending to the altitude of their place of birth (431 ± 380 and 2583 ± 334 meters above sea level (m a.s.l.), respectively). Both groups included top 3 finishers (including winners) in the general classification of Grand Tours and major races. Using data from both training and competitions during years 2013-2020 (8 ± 5 seasons per cyclist), we registered participants' mean maximal power (MMP) for efforts lasting 5 s, 30 s, 5 min, and 10 min, respectively, at altitudes ranging from 0-500 to >2000 m a.s.l. RESULTS: A significant altitude-MMP interaction effect (two-factor repeated-measures ANOVA) was found in lowlanders (P < 0.001) but not in altitude natives (P = 0.150). In lowlanders, individual performance decreased in a dose-response manner with increasing altitudes compared with sea (or near-sea) level (0-500 m a.s.l.), whereas this trend was much less evident in natives. A significant altitude-MMP-group effect was found (P < 0.001), with nonsignificant (and overall trivial-to-small differences) between lowlanders and altitude natives for any effort duration at altitudes ≤1500 m a.s.l. but with significant differences at higher altitudes (≥1501 m a.s.l.). CONCLUSIONS: Acute altitude exposure influences real-world performance differently in low landers and altitude natives, which might confer a competitive advantage to the latter, particularly in races including efforts at >1500 m a.s.l.

Reproducibility of Skin Temperature Response after Cold Stress Test Using the Game Ready System: Preliminary Study.

The objective of this preliminary study was to determine the reproducibility of lower limbs skin temperature after cold stress test using the Game Ready system. Skin temperature of fourteen participants was measured before and after cold stress test using the Game Ready system and it was repeated the protocol in four times: at 9:00, at 11:00, at 19:00, and at 9:00 h of the posterior day. To assess skin temperature recovery after cold stress test, a logarithmic equation for each region was calculated, and constant (ß0) and slope (ß1) coefficients were obtained. Intraclass correlation coefficient (ICC), standard error (SE), and within-subject coefficient of variation (CV) were determined. No differences were observed between measurement times in any of the regions for the logarithmic coefficients (p > 0.38). Anterior thigh (ß0 ICC 0.33-0.47; ß1 ICC 0.31-0.43) and posterior knee (ß0 ICC 0.42-0.58; ß1 ICC 0.28-0.57) were the regions with the lower ICCs, and the other regions presented values with a fair and good reproducibility (ICC > 0.41). Posterior leg was the region with the better reproducibility (ß0 ICC 0.68-0.78; ß1 ICC 0.59-0.74; SE 3-4%; within-subject CV 7-12%). In conclusion, cold stress test using Game Ready system showed a fair and good reproducibility, especially when the posterior leg was the region assessed.

Effect of cycling specialization on effort and physiological responses to uphill and flat cycling at similar intensity.

Power output is considered one of the best tools to control external loads in cycling, but the relationship between a target power output and the physiological responses may suffer from the effects of road gradient, which is also affected by cyclist specialization. The objective was to determine the effects of cyclist specialization on effort perception and physiological response (heart rate and lactate concentration) while sustaining efforts at similar power output but riding on two different road gradients. Nineteen male competitive road cyclists performed two randomized trials of 10 min at 0% (velodrome) and 10 min at 6% road gradient (field uphill), at an intensity of 10% ± 3% below the individual's functional threshold power. Cadence was kept between 75 and 80 rpm in both trials and posture remained unchanged during the tests. Heart rate, speed, cadence, power output, blood lactate, and rate of perceived effort were measured for each trial. K-means cluster analyses differentiate uphill (n = 10) and flat specialists (n = 9) according to lactate responses. Flat specialists presented lower heart rate (p < 0.001 and ES = 0.2), perceived exertion (p < 0.01 and ES = 0.7), and blood lactate concentration (p < 0.001 and ES = 0.7) riding on the flat than uphill. Uphill specialists presented lower perceived exertion (p < 0.01 and ES = 0.8) and blood lactate concentration (p < 0.01 and ES = 0.5) riding uphill than on the flat. In conclusion, the combination of cyclist specialization and road gradient affects physiological and effort perception parameters in response to a similar power output demand. These factors deserve attention in training schedules and monitoring performance using power output data.

Effect of a Marathon on Skin Temperature Response After a Cold-Stress Test and Its Relationship With Perceptive, Performance, and Oxidative-Stress Biomarkers.

CONTEXT: Although skin-temperature assessment has received much attention in recent years as a possible internal-load measurement, scientific evidence is scarce. PURPOSE: To analyze baseline skin temperature and its rewarming through means of a cold-stress test before and after performing a marathon and to study the association between skin temperature and internal/external-load measurements. METHODS: A total of 16 runners were measured 48 and 24 h before and 24 and 48 h after completing a marathon. The measurements on each day of testing included urine biomarkers of oxidative stress, pain and fatigue perception, skin temperature (at baseline and after a cold-stress test), and jump performance. RESULTS: Reduced jump performance (P < .01 and effect size [ES] = 0.5) and higher fatigue and pain perception were observed 24 h after the marathon (P < .01 and ES > 0.8). Although no differences in baseline skin temperature were observed between the 4 measuring days, posterior legs presented lower constant (P < .01 and ES = 1.4) and higher slope (P = .04 and ES = 1.1) parameters in the algorithmic equations fitted for skin-temperature recovery after the cold-stress test 24 h after the marathon than on the day before the marathon. Regressions showed that skin-temperature parameters could be predicted by the ratio of ortho-tyrosine isomer to phenylalanine (oxidative stress biomarker) and body fat composition, among others. CONCLUSIONS: Although baseline skin temperature was not altered 24 or 48 h after a marathon, the application of cold stress after the marathon would appear to be a good method for providing information on vasoconstriction and a runner's state of stress.

A preliminary investigation about the observation of regional skin temperatures following cumulative training loads in triathletes during training camp.

There are controversial results in the literature concerning the concept that cumulative training load could affect basal skin temperature in the days following training sessions. The objective was to measure skin temperature in triathletes during a training camp with cumulative training load. Ten male recreational triathletes involved in a training camp underwent measurements of perception of pain and fatigue (visual analogue scale), skin temperature (infrared thermography), and jump performance (counter movement jump test) before, one day, and two days after the beginning of the training camp. All measurements were performed before the breakfast. Jump height did not differ between the days (p > 0.05). Fatigue perception increased after the first and second day of training for most of the body regions (p < 0.05). Pain perception increased after two days of training (p < 0.05). Mean and maximum skin temperature increased after the second day of training for most of the body regions (p < 0.05). Skin temperature in some body regions was directly related with muscle mass, weekly training volume, and inverse related with fatigue perception (p < 0.05 and R2 > 0.4). Possible explanations of these results in comparison with previous studies may include the influence of control of the intrinsic and extrinsic factors related to the skin temperature assessment (for instance, the time of the day, lack of muscle soreness, daily activity control). These preliminary results have important implication on the use of skin basal temperature data to monitor exercise recovery, which claims for further research.