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Reproducibility of Performance Changes to Simulated Live High/Train Low Altitude
Abstract
Elite athletes often undertake multiple altitude exposures within and between training years in an attempt to improve sea level performance.
To quantify the reproducibility of responses to live high/train low (LHTL) altitude exposure in the same group of athletes.
Sixteen highly trained runners with maximal aerobic power (VO2max) of 73.1 +/- 4.6 and 64.4 +/- 3.2 mL x kg(-1) x min(-1) (mean +/- SD) for males and females, respectively, completed 2 x 3-wk blocks of simulated LHTL (14 h x d(-1), 3000 m) or resided near sea level (600 m) in a controlled study design. Changes in the 4.5-km time trial performance and physiological measures including VO2max, running economy and hemoglobin mass (Hb(mass)) were assessed.
Time trial performance showed small and variable changes after each 3-wk altitude block in both the LHTL (mean [+/-90% confidence limits]: -1.4% [+/-1.1%] and 0.7% [+/-1.3%]) and the control (0.5% [+/-1.5%] and -0.7% [+/-0.8%]) groups. The LHTL group demonstrated reproducible improvements in VO2max (2.1% [+/-2.1%] and 2.1% [+/-3.9%]) and Hb(mass) (2.8% [+/-2.1%] and 2.7% [+/-1.8%]) after each 3-wk block. Compared with those in the control group, the runners in the LHTL group were substantially faster after the first 3-wk block (LHTL - control = -1.9% [+/-1.8%]) and had substantially higher Hb(mass) after the second 3-wk block (4.2% [+/-2.1%]). There was no substantial difference in the change in mean VO2max between the groups after the first (1.2% [+/-3.3%]) or second 3-wk block (1.4% [+/-4.6%]).
Three-week LHTL altitude exposure can induce reproducible mean improvements in VO2max and Hb(mass) in highly trained runners, but changes in time trial performance seem to be more variable. Competitive performance is dependent not only on improvements in physiological capacities that underpin performance but also on a complex interaction of many factors including fitness, fatigue, and motivation.
... [3][4][5] Nevertheless, some evidence suggests that LHTL combined with intermittent training in hypoxia (namely "live high-train low and high", LHTLH in the present study) may elicit greater enhancement in the physiological capacities than more traditional LHTL. 6,7 Altitude training is commonly used among crosscountry (XC) skiers as they attempt to improve their performance. 8,9 Increased performance following altitude training is attributed to an increase in hemoglobin mass (Hb mass ) that is associated with an increase in maximal oxygen uptake (VO 2max ) 10 and exercise performance, assuming that the athlete has been able to maintain a normal pace during high intensity training. ...
... 27 In contrast, several studies have found an increase in time trial performance and/or VO 2max when performance was measured within 3 days after normobaric LHTL. 7,25,28 Taken together, although the timing of post performance measurements were in line with the general experiences of "good timing" for post-altitude performance, 3 some scientific evidence suggests that athletes perform better during the third and fourth week after altitude exposure. 26,27 As such, it is possible that the positive performance effects of LHTLH appeared later than measured in the present study. ...
... Notably, LHTLH resulted in greater enhancement in VO 2max than "live low, train high" and LHTL methods. 6,7 Regardless, it is difficult to conclude, whether 2 h week −1 of LIT in normobaric hypoxia, that was used in the present study, had any additional effect on Hb mass or endurance performance compared to the LHTL training. Although technological developments have made the implementation of normobaric LHTLH training quite easy, while reducing travel stress, more data is needed from the combination of living and training in normobaric hypoxia. ...
Purpose
To investigate whether 4 weeks of normobaric “live high–train low and high” (LHTLH) causes different hematological, cardiorespiratory, and sea‐level performance changes compared to living and training in normoxia during a preparation season.
Methods
Nineteen (13 women, 6 men) cross‐country skiers competing at the national or international level completed a 28‐day period (∼18 h day⁻¹) of LHTLH in normobaric hypoxia of ∼2400 m (LHTLH group) including two 1 h low‐intensity training sessions per week in normobaric hypoxia of 2500 m while continuing their normal training program in normoxia. Hemoglobin mass (Hbmass) was assessed using a carbon monoxide rebreathing method. Time to exhaustion (TTE) and maximal oxygen uptake (VO2max) were measured using an incremental treadmill test. Measurements were completed at baseline and within 3 days after LHTLH. The control group skiers (CON) (seven women, eight men) performed the same tests while living and training in normoxia with ∼4 weeks between the tests.
Results
Hbmass in LHTLH increased 4.2 ± 1.7% from 772 ± 213 g (11.7 ± 1.4 g kg⁻¹) to 805 ± 226 g (12.5 ± 1.6 g kg⁻¹) (p < 0.001) while it was unchanged in CON (p = 0.21). TTE improved during the study regardless of the group (3.3 ± 3.4% in LHTLH; 4.3 ± 4.8% in CON, p < 0.001). VO2max did not increase in LHTLH (61.2 ± 8.7 mL kg⁻¹ min⁻¹ vs. 62.1 ± 7.6 mL kg⁻¹ min⁻¹, p = 0.36) while a significant increase was detected in CON (61.3 ± 8.0–64.0 ± 8.1 mL kg⁻¹ min⁻¹, p < 0.001).
Conclusions
Four‐week normobaric LHTLH was beneficial for increasing Hbmass but did not support the short‐term development of maximal endurance performance and VO2max when compared to the athletes who lived and trained in normoxia.
... Of the 15 athletes who completed multiple altitude training camps during the observation period, 27% always experienced increases in Hbmass, 13% only had decreases, and 60% had both positive and negative results [81]. Finally, in highly trained runners completing two, three week blocks of LHTL interspersed by a ive week washout period near-to sea-level, reproducible mean improvements in VȮ 2max and Hb mass of ~ 3% were reported after each block, however these did not translate to reproducible improvements in time-trial performance, with mean changes of 1.4% faster and 0.7% slower being observed respectively [91]. Additionally, there was a lack of association between changes in block one versus block two, with moderate but unclear correlations for VȮ 2max and Hb mass , and only a trivial correlation for time-trial performance [91]. ...
... Finally, in highly trained runners completing two, three week blocks of LHTL interspersed by a ive week washout period near-to sea-level, reproducible mean improvements in VȮ 2max and Hb mass of ~ 3% were reported after each block, however these did not translate to reproducible improvements in time-trial performance, with mean changes of 1.4% faster and 0.7% slower being observed respectively [91]. Additionally, there was a lack of association between changes in block one versus block two, with moderate but unclear correlations for VȮ 2max and Hb mass , and only a trivial correlation for time-trial performance [91]. Together, these studies suggest the erythropoietic and Hb mass response to altitude does not appear to be a ixed trait, and thus it would appear unlikely that the individual variability in the performance response to hypoxia is related solely to this pathway. ...
... Together, these studies suggest the erythropoietic and Hb mass response to altitude does not appear to be a ixed trait, and thus it would appear unlikely that the individual variability in the performance response to hypoxia is related solely to this pathway. Furthermore, the intra-individual diferences reported [73,91], indicate that the performance response to altitude is not consistent and dependent solely on physiological adaptations, but also itness, training status, fatigue and timing of competition, which require individual management to ensure optimal performance [91]. Measurement of peripheral oxygen saturation at rest (SpO 2 ) may reveal information regarding an athlete's haematological response to altitude [84]. ...
Live high train high (LHTH) is the original method of altitude training used by elite athletes to enhance sea-level performance. Whilst many anecdotal reports featuring world-class performances of elite athletes at sea-level following LHTH exist, well-controlled studies of elite athletes using altitude training under ecologically valid conditions with training well characterised are still lacking. The literature is equivocal when considering the ergogenic potential of LHTH, and given the majority of controlled studies do not report enhanced sea-level performance, some scepticism regarding the efficacy of LHTH persists. Despite this, LHTH remains a popular form of altitude training utilised by elite athletes, with numerous case studies of champion athletes employing LHTH solidifying the rationale for its use during preparation for competition. Discussion of factors affecting the response to LHTH are often related to compromising either the hypoxia induced acceleration of erythropoiesis and production of red blood cells, or the maintenance of oxygen flux and training intensity at altitude. Regarding the former, iron status and supplementation, as well as hypoxic dose are often mentioned. Concerning the latter, reduced oxygen availability at altitude leading to athletes training at lower absolute intensities and the relative intensity of training sessions being clamped as equivalent to sea-level, thus also reducing absolute training intensity are frequently discussed. Other factors including immune function and the timing of competition following LHTH may also contribute to an observed performance. Less considered in the literature are those factors specific to elite athletes, namely the repeated use of altitude camps throughout a season, and the influence this may have on subsequent performance. The current narrative review aimed to summarise the current literature pertaining to LHTH in elite athletes, and furthermore describe several factors affecting performance following altitude training.
... [1][2][3] Although average increases in Hb mass are commonly observed, the responses are highly variable between individuals at a specific camp and within individuals when the altitude sojourns are repeated. [4][5][6][7][8] What causes the intra-individual variability in Hb mass response to repeated altitude sojourns is currently unknown. ...
... Moreover, we observed substantial intra-individual variations in the altitude-induced change in Hb mass (CV intra : 88%), strengthening that responders and non-responders are not a "fixed trait". This is in line with most previous investigations that have found substantial intra-individual variations in Hb mass responses over 2-5 altitude sojourns, [5][6][7][8] showing that it is not possible to predict future Hb mass responses based on only one altitude sojourn. [4][5][6][7][8] F I G U R E 2 (A) The relationship between the percent change in hemoglobin mass (Hb mass ) from before to after an altitude sojourn and the prealtitude Hb mass , expressed as the percent deviation from the individual mean baseline (n = 34). ...
... This is in line with most previous investigations that have found substantial intra-individual variations in Hb mass responses over 2-5 altitude sojourns, [5][6][7][8] showing that it is not possible to predict future Hb mass responses based on only one altitude sojourn. [4][5][6][7][8] F I G U R E 2 (A) The relationship between the percent change in hemoglobin mass (Hb mass ) from before to after an altitude sojourn and the prealtitude Hb mass , expressed as the percent deviation from the individual mean baseline (n = 34). (B) Individual (points and lines) and mean (bars) between sojourns coefficient of variation in preand post-altitude Hb mass ...
Introduction
Previous studies have shown variable within‐subject hemoglobin mass (Hbmass) responses to altitude training. We investigated whether Hbmass responses depend on individual variations in pre‐altitude Hbmass during repeated altitude sojourns.
Methods
Nine elite endurance athletes carried out 3–5 altitude sojourns over 17 ± 10 months (mean ± 95% confidence interval), at an altitude of 1976 ± 62 m, for 21 ± 1 days, and a total hypoxic dose of 989 ± 46 km·h, with Hbmass assessed before and after each sojourn (carbon monoxide rebreathing). The individual mean baseline was calculated as the mean of all pre‐altitude Hbmass values for an athlete, and it was investigated whether the percent deviation from the individual mean baseline affected the altitude‐induced Hbmass response.
Results
On average, Hbmass increased by 3.4 ± 1.1% (p < 0.001) from pre‐ to post‐altitude. The intra‐individual changes in Hbmass were highly inconsistent (coefficient of variation, CV: 88%), and we found no relationship between Hbmass changes in successive altitude sojourns (r = 0.01; p = 0.735). However, the percent increase in Hbmass was highly correlated with the pre‐altitude Hbmass, expressed as the percent deviation from the individual mean baseline (y = −0.7x + 3.4; r = 0.75; p < 0.001). Linear mixed‐model analysis confirmed a −0.6 ± 0.2% smaller increase in Hbmass for each 1% higher pre‐altitude Hbmass than the individual mean baseline (p < 0.001) after adjusting for the covariates hypoxic dose (p = 0.032) and the relative Hbmass (g·kg⁻¹ body weight; p = 0.031).
Conclusion
Individual variations in pre‐altitude Hbmass significantly influence the athletes' Hbmass responses to repeated altitude sojourns, with a potentiated response after traveling to altitude with a low pre‐altitude Hbmass.
... Only eight of the scientific studies had a control group for their interventions [20,22,24,25,[27][28][29]31]. The control groups of the studies [20,22,24,27,28] did not receive the hypoxia at rest, while their corresponding intervention groups did. ...
... Study location Only eight of the scientific studies had a control group for their interventions [20,22,24,25,[27][28][29]31]. The control groups of the studies [20,22,24,27,28] did not receive the hypoxia at rest, while their corresponding intervention groups did. ...
... The studies took place in different countries: four in Japan [26][27][28][29], two in Australia [30,31], two in France [22,25], one in The United States [20], one in Russia [23], one in Austria [24] and one in England [21]. ...
Background:
The use of normobaric hypoxia can bring benefits to sports performance because it improves haematological parameters and/or physical activity tests. Our objective was to conduct a systematic review so as to analyse the methods used in hypoxia and to detect its effects on middle- and/or long-distance runners.
Methods:
Research was conducted using five electronic databases (PubMed, SportDiscus, Cochrane Library, Scopus and PEDro) until December 2021. The methodological quality of the included studies was assessed using the PEDro scale.
Results:
Having analysed 158 studies, 12 were chosen for the qualitative and quantitative synthesis. A significant improvement on time until exhaustion was detected, and oxygen saturation decreased after the intervention. There were no significant changes in the 3000-metre time trial or in the haematocrit percentage. The changes in percentage of reticulocytes, heart rate, maximal heart rate, lactate concentration and erythropoietin were heterogeneous between the different research studies.
Conclusion:
short exposure (less than 3 h to normobaric hypoxia significantly increases the time to exhaustion). However, longer exposure times are necessary to increase haemoglobin. Altitude and exposure time are highly heterogeneous in the included studies.
... Interestingly, these results showed that hypobaric and normobaric LHTL evoked similar group mean increases in Hb mass (4.1 vs. 4.5%) and that there was no difference between the two hypoxic conditions. In line with previous studies (6,8,24,30,38,43), individual Hb mass responses demonstrated a wide variability (-1.4 to 10.6%) in hypobaric and normobaric LHTL. Because the number of athletes was small within the hypobaric hypoxia (HH) and normobaric hypoxia (NH) groups (n ϭ 10, 11), an uneven distribution of athletes who responded positively or less positive to altitude in Hb mass may have affected the outcome. ...
... This is comparable to our previously published paper (16) where we reported also a correlation (r ϭ Ϫ0.64, P ϭ 0.002) between running performance improvements and increase in Hb mass (g/kg) after 18 days of LHTL (n ϭ 21), suggesting that the enhancement in endurance performance was directly linked to changes in Hb mass after LHTL, whereas there was no significant correlation between percent changes in individual performance and Hb mass (in g) in HH (r ϭ Ϫ0.14, P ϭ 0.61) or NH (r ϭ Ϫ0.35, P ϭ 0.20). This in turn supports the literature showing an increase in Hb mass following altitude training with different performance outcomes (7,12,30). Furthermore, it seems that also nonhematological mechanisms such as improved mitochondrial efficiency and/or muscle pH regulation (13) can contribute to enhanced sea level performance following altitude training. Thus, the impact of Hb mass increase on performance benefits following altitude training remains unclear. ...
... Individual Hb mass responses and reproducibility. Individual variability in Hb mass response to altitude training camps in either HH or NH has previously been shown and discussed (6,8,16,38,43); however, not many altitude training studies quantified individual responsiveness (24,27,29,30). In the present study, individual Hb mass responsiveness (measure of individual responses that is free from the TE) was Ϯ0.9% in HH and Ϯ1.7% in NH, which was slightly lower compared with other studies demonstrating individual Hb mass responsive-ness of Ϯ1.3 to Ϯ2.6% in HH (24,29) and of Ϯ1.4 to Ϯ2.9% in NH (27,30). ...
Introduction For elite endurance athletes the primary aim of the LHTL strategy is to improve sea-level endurance performance by increasing hemoglobin mass (Hbmass) (Saunders, Pyne, & Gore, 2009). So far, no study compared Hbmass changes after the same hypoxic dose to normobaric and hypobaric live-high train-low (LHTL) camp, it remains unclear for endurance athletes whether they should perform a LHTL training camp rather under normobaric hypoxia (NH) or hypobaric hypoxia (HH). Therefore, the aim of the study was to compare Hbmass changes between normobaric and hypobaric LHTL after the same hypoxic dose and in response to 18-days LHTL training camp in either HH or NH.
... cycling protocols used have been described previously (5,19). The typical error for VO 2 peak in our laboratory is 2% (20). ...
... Similarly, other inhibitors to erythropoietic adaptation, such as hypoxic dose (7), low energy availability (8), illness (9), injury (10) are unlikely to explain the difference since athletes across all three groups lived and trained together, with no noteworthy injuries or illnesses occurring. Further, the large variation in our results (as indicated by the large SDs of each group), highlights the individual response to altitude reported previously (20,31). ...
... whilst Robertson et al reported that a six week wash-out period between altitude exposures was sufficient for Hbmass to return to baseline levels following an identical simulated LHTL protocol (20). In the present study, the elevated Hbmass levels of the IV group persisted slightly longer than the ORAL group, returning to pre-altitude levels by six weeks post-exposure, It must also be acknowledged that iron supplementation ceased in both supplemented groups upon cessation of the altitude exposure (the last IV injection was administered midway through A C C E P T E D the exposure). ...
Purpose:
Iron is integral for erythropoietic adaptation to hypoxia, yet the importance of supplementary iron compared to existing stores is poorly understood. The aim of the present study was to compare the magnitude of the haemoglobin mass (Hbmass) response to altitude in athletes supplemented with intravenous (IV), oral or placebo iron supplementation.
Methods:
Thirty-four, non-anaemic, endurance-trained athletes completed 3 weeks of simulated altitude (3000 m, 14h.d), receiving either 2-3 bolus iron injections (ferric carboxymaltose), daily oral iron supplementation (ferrous sulphate) or a placebo, commencing 2 weeks prior to and throughout altitude exposure. Hbmass and markers of iron regulation were assessed at baseline (day -14), immediately prior to (day 0), weekly during (days 8, 15), and immediately, 1, 3 and 6 weeks after the completion of altitude exposure (days 22, 28, 42 and 63).
Results:
Hbmass significantly increased following altitude in IV (Mean%, [90% CI]: 3.7%, [2.8, 4.7]) and oral (3.2%, [2.2, 4.2]), and remained elevated at 7 days post-altitude in oral (2.9%, [1.5, 4.3]) and 21 days post in IV (3.0%, [1.5, 4.6]). Hbmass was not significantly higher than baseline at any time point in placebo.
Conclusion:
Iron supplementation appears necessary for optimal erythropoietic adaptation to altitude exposure. Intravenous iron supplementation during three weeks of simulated LHTL altitude training offered no additional benefit in terms of the magnitude of the erythropoietic response for non-anaemic endurance athletes compared to oral supplementation.
... cycling protocols used have been described previously (5,19). The typical error for VO 2 peak in our laboratory is 2% (20). ...
... Similarly, other inhibitors to erythropoietic adaptation, such as hypoxic dose (7), low energy availability (8), illness (9), injury (10) are unlikely to explain the difference since athletes across all three groups lived and trained together, with no noteworthy injuries or illnesses occurring. Further, the large variation in our results (as indicated by the large SDs of each group), highlights the individual response to altitude reported previously (20,31). ...
... whilst Robertson et al reported that a six week wash-out period between altitude exposures was sufficient for Hbmass to return to baseline levels following an identical simulated LHTL protocol (20). In the present study, the elevated Hbmass levels of the IV group persisted slightly longer than the ORAL group, returning to pre-altitude levels by six weeks post-exposure, It must also be acknowledged that iron supplementation ceased in both supplemented groups upon cessation of the altitude exposure (the last IV injection was administered midway through A C C E P T E D the exposure). ...
The integrity of Athlete Biological Passport (ABP) is underpinned by understanding normal fluctuations of its biomarkers to environmental or medical conditions, e.g. altitude training or iron deficiency. The combined impact of altitude and iron supplementation on the ABP was evaluated in endurance-trained athletes (n=34) undertaking 3-weeks of simulated live-high: train-low (14 h.d-1, 3000m). Athletes received either oral, intravenous (IV) or placebo iron supplementation, commencing two weeks prior and continuing throughout hypoxic exposure. Venous blood was sampled twice prior, weekly during, and up to 6-weeks after altitude. Individual ABP thresholds for haemoglobin concentration ([Hb]), reticulocyte percentage (%retic), and OFF score were calculated using the adaptive model and assessed at 99% and 99.9% specificity. Eleven athletes returned values outside of the calculated reference ranges at 99%, with 8 at 99.9%. The percentage of athletes exceeding the thresholds in each group was similar, but IV returned the most individual occurrences. A similar frequency of abnormalities occurred across the three biomarkers, with abnormal [Hb] and OFF score values arising mainly during-, and %retic values mainly post- altitude. Removing samples collected during altitude from the model resulted in ten athletes returning abnormal values at 99% specificity, two of whom had not triggered the model previously. In summary, the abnormalities observed in response to iron supplementation and hypoxia were not systematic and mostly in line with expected physiological adaptations. They do not represent a uniform weakness in the ABP. Nevertheless, altitude training and iron supplementation should be carefully considered by experts evaluating abnormal ABP profiles.
... Several studies have demonstrated small but significant improvements in run timetrial performance for 3 km (28,37) and 5 km (17) after 2-4 wk of LHTL. However, not all studies have shown improvements for similar distances (27). This lack of consistent improvement is suggested to be related to a number factors, not limited to the extent of physiological adaptation incurred, the hypoxic dose, and the training status of the athletes (4). ...
... Similarly, the present study revealed that H + H had a 3.8% T 1.8% increase in Hb mass with~290 h of hypoxic exposure, whereas no increases occurred in HOT and CONT. Despite H + H having an increase in Hb mass , the lack of performance changes in H + H supports previous research showing that the changes in Hb mass from the hypoxic exposure have minimal impact on 3-km TT performance (27). ...
... Considering no associations were observed between the measured physiological adaptations and 3-km TT performance, other unmeasured physiological adaptations, not limited to enhanced thermoregulatory regulation, increased cardiac and skeletal muscle metabolic efficiency (21), or nonphysiological factors may provide explanations for the observed performance responses. The uncoupling of performance and physiology changes is not uncommon in trained individuals (27), and factors such as perception of effort, motivation, and fatigue can contribute to overall endurance performance outcomes (23). At the 3-km TT at 3wkP, fatigue was increased in H + H, despite TL being reduced during the nonexposure period. ...
Introduction:
Independent heat and hypoxic exposure can enhance temperate endurance performance in trained athletes, although their combined effects remain unknown. This study examined whether the addition of heat interval training during 'Live High, Train Low' (LHTL) hypoxic exposure would result in enhanced performance and physiological adaptations as compared to heat or temperate training.
Methods:
Twenty-six well-trained runners completed three weeks of interval training assigned to one of three conditions: 1) LHTL hypoxic exposure plus heat training (H+H; 3000 m for 13 h·day, train at 33°C, 60% RH), 2) heat training with no hypoxic exposure (HOT, live at <600m and train at 33°C, 60% RH), or 3) temperate training with no hypoxic exposure (CONT; live at <600m and train at 14°C, 55% RH). Performance 3-km time-trials (3-km TT), running economy (RE), haemoglobin mass (Hbmass) and plasma volume (PV) were assessed utilising magnitude based inferences statistical approach before (Baseline), after (Post), and three weeks (3wkP) following exposure.
Results:
Compared to Baseline, 3-km TT performance was likely increased in HOT at 3wkP (-3.3%; ±1.3% (mean; ±90% CL)), with no performance improvement in either H+H or CONT. Hbmass increased by 3.8%; ±1.8% at Post in H+H only. PV in HOT was possibly elevated above H+H and CONT at Post but not at 3wkP. Correlations between changes in 3-km TT performance and physiological adaptations were unclear.
Conclusion:
Incorporating heat-based training into a three week training block can improve temperate performance at three weeks following exposure, with athlete psychology, physiology and environmental dose all important considerations. Despite haematological adaptations, the addition of LHTL to heat interval training has no greater 3-km TT performance benefit than temperate training alone.
... Because in all athletes, no depleted ferritin stores (Ftn 930 KgIL j1 ) (16), doping abuse (doping CON scores within normal ranges (31)), or different daily training loads during the altitude stay were detected, and all measures were performed in duplicate with no measurement outliers, it can be expected that the athletes who exceeded the 95% CL were ''true'' Hb mass responders to altitude training at 2250 m in either NH or HH. Individual variability in Hb mass response to LHTL training camps (2700-3000 m) in either HH or NH has been shown and discussed before (7,15,29). However, studies (7,12,15,23,26,29,40) that focused on individual Hb mass response were mainly based on single measures of Hb mass with the optimized CO rebreathing method, which makes the differentiation between physiological and technical variation more difficult. ...
... Individual variability in Hb mass response to LHTL training camps (2700-3000 m) in either HH or NH has been shown and discussed before (7,15,29). However, studies (7,12,15,23,26,29,40) that focused on individual Hb mass response were mainly based on single measures of Hb mass with the optimized CO rebreathing method, which makes the differentiation between physiological and technical variation more difficult. The optimized CO rebreathing method is a very precise tool for determining Hb mass in athletes with a TE of approximately 2% (14). ...
... Changes in running and cycling performance were likely beneficial (64%-80% positive) in the HH and NH groups compared with the CON group ( Table 2). The greater performance improvement in the altitude groups (+1.2% to +2.2%) compared with the CON group is of similar magnitude as reported in other LHTL training interventions under normobaric conditions (13,29) and under hypobaric conditions (39,41), whereas the differences between HH and NH in the magnitude of performance changes were unclear. Bonetti and Hopkins (3) reported in a recent meta-analysis on altitude training that natural LHTL might be more beneficial for elite (4.0%; 90% CL T3.7% vs 0.6%; T2.0%) and subelite (4.2%; 90% CL T2.9% vs 1.4%; T2.0%) athletes than artificial protocols. ...
PURPOSE: To compare hemoglobin mass (Hbmass) changes during an 18-d live high-train low (LHTL) altitude training camp in normobaric hypoxia (NH) and hypobaric hypoxia (HH). METHODS: Twenty-eight well-trained male triathletes were split into three groups (NH: n = 10, HH: n = 11, control [CON]: n = 7) and participated in an 18-d LHTL camp. NH and HH slept at 2250 m, whereas CON slept, and all groups trained at altitudes <1200 m. Hbmass was measured in duplicate with the optimized carbon monoxide rebreathing method before (pre-), immediately after (post-) (hypoxic dose: 316 vs 238 h for HH and NH), and at day 13 in HH (230 h, hypoxic dose matched to 18-d NH). Running (3-km run) and cycling (incremental cycling test) performances were measured pre and post. RESULTS: Hbmass increased similar in HH (+4.4%, P < 0.001 at day 13; +4.5%, P < 0.001 at day 18) and NH (+4.1%, P < 0.001) compared with CON (+1.9%, P = 0.08). There was a wide variability in individual Hbmass responses in HH (-0.1% to +10.6%) and NH (-1.4% to +7.7%). Postrunning time decreased in HH (-3.9%, P < 0.001), NH (-3.3%, P < 0.001), and CON (-2.1%, P = 0.03), whereas cycling performance changed nonsignificantly in HH and NH (+2.4%, P > 0.08) and remained unchanged in CON (+0.2%, P = 0.89). CONCLUSION: HH and NH evoked similar Hbmass increases for the same hypoxic dose and after 18-d LHTL. The wide variability in individual Hbmass responses in HH and NH emphasizes the importance of individual Hbmass evaluation of altitude training.
... The reproducible effect of a transition to altitude upon iron metabolism has been clearly demonstrated in athletes. In hypoxia, erythropoietin increased and sFer decreased while a slow increase in tHb-mass occurred over 3 weeks at a simulated altitude of 3000 m in male and female endurance athletes (Robertson et al., 2010). Furthermore, in an analysis of data from the Australian Institute of Sport database (n = 147 athletes), iron-deficient athletes provided with iron supplementation while resident in normobaric hypoxia (simulated altitude), demonstrated the greatest increase in tHb-mass (Garvican-Lewis, Govus, Peeling, Abbiss, & Gore, 2016). ...
... Furthermore, in an analysis of data from the Australian Institute of Sport database (n = 147 athletes), iron-deficient athletes provided with iron supplementation while resident in normobaric hypoxia (simulated altitude), demonstrated the greatest increase in tHb-mass (Garvican-Lewis, Govus, Peeling, Abbiss, & Gore, 2016). Conversely, upon return to sea level, iron status improves, causing a rise in ferritin (Robertson et al., 2010). Thus, removing the hypoxic stimulus may correct an imbalance between iron availability and erythropoietic drive. ...
Maintaining a positive iron balance is essential for female athletes to avoid the effects of iron deficiency and anaemia and to maintain or improve performance. A major function of iron is in the production of the oxygen and carbon dioxide carrying molecule, haemoglobin, via erythropoiesis. Iron balance is under the control of a number of factors including the peptide hormone hepcidin, dietary iron intake and absorption, environmental stressors (e.g. altitude), exercise, menstrual blood loss and genetics. Menstruating females, particularly those with heavy menstrual bleeding are at an elevated risk of iron deficiency. Haemoglobin concentration [Hb] and serum ferritin (sFer) are traditionally used to identify iron deficiency, however, in isolation these may have limited value in athletes due to: (1) the effects of fluctuations in plasma volume in response to training or the environment on [Hb], (2) the influence of inflammation on sFer and (3) the absence of sport, gender and individually specific normative data. A more detailed and longitudinal examination of haematology, menstrual cycle pattern, biochemistry, exercise physiology, environmental factors and training load can offer a superior characterisation of iron status and help to direct appropriate interventions that will avoid iron deficiency or iron overload. Supplementation is often required in iron deficiency; however, nutritional strategies to increase iron intake, rest and descent from altitude can also be effective and will help to prevent future iron deficient episodes. In severe cases or where there is a time-critical need, such as major championships, iron injections may be appropriate.
... Both natural LHTH and simulated live-high, train-low (LHTL) camps have reported average increases of tHbmass ranging from 2.0% to 4.1% [27,31,67] [27,57]. Analysis by Chapman et al. [20] suggested that significant improvement in 5000-m run time was a result of a greater acute and sustained increase in EPO, and therefore increase in total red cell volume and VO 2max . ...
PurposeElite endurance runners frequently utilise live high-train high (LHTH) altitude training to improve endurance performance at sea level (SL). Individual variability in response to the hypoxic exposure have resulted in contradictory findings. In the present case study, changes in total haemoglobin mass (tHbmass) and physiological capacity, in response to 4-weeks of LHTH were documented. We tested if a hypoxic sensitivity test (HST) could predict altitude-induced adaptations to LHTH.Methods
Fifteen elite athletes were selected to complete 4-weeks of LHTH (~ 2400 m). Athletes visited the laboratory for preliminary testing (PRE), to determine lactate threshold (LT), lactate turn point (LTP), maximal oxygen uptake VO2max and tHbmass. During LHTH, athletes completed daily physiological measures [arterial oxygen saturation (SpO2) and body mass] and subjective wellbeing questions. Testing was repeated, for those who completed the full camp, post-LHTH (POST). Additionally, athletes completed the HST prior to LHTH.ResultsA difference (P < 0.05) was found from PRE to POST in average tHbmass (1.8% ± 3.4%), VO2max (2.7% ± 3.4%), LT (6.1% ± 4.6%) and LTP (5.4% ± 3.8%), after 4-weeks LHTH. HST revealed a decrease in oxygen saturation at rest (ΔSpr) and higher hypoxic ventilatory response at rest (HVRr) predicted individual changes tHbmass. Lower hypoxic cardiac response at rest (HCRr) and higher HVRr predicted individual changes VO2max.Conclusion
Four weeks of LHTH at ~ 2400 m increased tHbmass and enhanced physiological capacity in elite endurance runners. There was no observed relationship between these changes and baseline characteristics, pre-LHTH serum ferritin levels, or reported incidents of musculoskeletal injury or illness. The HST did however, estimate changes in tHbmass and VO2max. HST prior to LHTH could allow coaches and practitioners to better inform the acclimatisation strategies and training load application of endurance runners at altitude.
... L'entraînement, et plus précisément le type d'entraînement (e.g., qualitatif vs quantitatif) va conditionner la performance en générant notamment des stimuli en lien avec la charge définie (i.e., intensité, volume, durée, fréquence d' entraînement, récupération) afin d'augmenter les capacités de l'athlète[8,9,202,[212][213][214]. Si l'entraînement est bien calibré, diverses adaptations physiologiques comme l'érythropoïèse et l'angiogenèse vont permettre par exemple d'améliorer l'apport en oxygène des cellules musculaires[215][216][217][218][219]. ...
Cette thèse avait pour objectif de présenter les différents travaux réalisés sur la prédiction de la performance en course à pied afin d’aider les athlètes et les entraîneurs à optimiser leur processus d’entraînement. Ces études, en collaboration avec la Fédération Française d’Athlétisme (FFA), se sont appuyées sur le système d’information fédéral répertoriant notamment l’ensemble des résultats athlétiques, les bilans ou encore le nombre de licenciés. La première étude avait pour objectif d’exposer l’évolution des performances françaises des courses de demi-fond et de fond chez les femmes. Les études suivantes étaient principalement destinées à tester la validité, la justesse, et la précision de différentes méthodes de prédiction (i.e., capacité à prédire les performances) sur des performances individuelles réelles d’athlètes de différents niveaux, hommes et/ou femmes. Les résultats se sont avérés valides et précis, quelle que soit la méthode de prédiction utilisée. Enfin, la dernière recherche était destinée à la prédiction du potentiel de performance. Cette étude a notamment mis en avant une analyse du taux d'amélioration des performances en demi-fond et en fond précédant la réalisation de records personnels chez les hommes et chez les femmes. Un index de progression à visée pratique, a également été proposé, afin d’évaluer l’évolution des performances et permettre une éventuelle détection et orientation des athlètes au fort potentiel.
... Previous research investigating mechanisms which aid in mitigating the detrimental effects of hypoxia on performance have focused largely on physiological mechanisms such as dietary nitrate supplementation (Vanhatalo et al., 2011;Muggeridge et al., 2013), inspiratory muscle training (Downey et al., 2007), and acclimatization strategies (Robertson et al., 2010;Humberstone-Gough et al., 2013). Whilst these interventions have been shown to improve physical and cognitive performance, limited research has investigated the potential impact of psychological interventions to aid in mitigating performance decrements, despite psychological impairment being characteristic of hypoxia (Bahrke and Shukitt-Hale, 1993;Virués-Ortega et al., 2004). ...
Humans exposed to hypoxia are susceptible to physiological and psychological impairment. Music has ergogenic effects through enhancing psychological factors such as mood, emotion, and cognition. This study aimed to investigate music as a tool for mitigating the performance decrements observed in hypoxia. Thirteen males (mean ± SD; 24 ± 4 years) completed one familiarization session and four experimental trials; (1) normoxia (sea level, 0.209 FiO2) and no music; (2) normoxia (0.209 FiO2) with music; (3) normobaric hypoxia (∼3800 m, 0.13 FiO2) and no music; and (4) normobaric hypoxia (0.13 FiO2) with music. Experimental trials were completed at 21°C with 50% relative humidity. Music was self-selected prior to the familiarization session. Each experimental trial included a 15-min time trial on an arm bike, followed by a 60-s isometric maximal voluntary contraction (MVC) of the biceps brachii. Supramaximal nerve stimulation quantified central and peripheral fatigue with voluntary activation (VA%) calculated using the doublet interpolation method. Average power output (W) was reduced with a main effect of hypoxia (p = 0.02) and significantly increased with a main effect of music (p = 0.001). When combined the interaction was additive (p = 0.87). Average MVC force (N) was reduced in hypoxia (p = 0.03) but VA% of the biceps brachii was increased with music (p = 0.02). Music reduced subjective scores of mental effort, breathing discomfort, and arm discomfort in hypoxia (p < 0.001). Music increased maximal physical exertion through enhancing neural drive and diminishing detrimental mental processes, enhancing performance in normoxia (6.3%) and hypoxia (6.4%).
... El entrenamiento en altitud utiliza dos enfoques principales en busca de aumentos en el rendimiento deportivo: "vivir bajo y entrenar alto" [31,32] y "vivir alto-entrenar bajo" [33,34], con altitudes que pueden ir desde los 2300 hasta los 5700 m.s.n.m [35]. En altitud natural, el organismo puede presentar efectos adversos como el mal de montaña (a tan solo 2500 m.s.n.m). ...
Introducción: en la actualidad, los entrenadores buscan la manera de mejorar las capacidades físicas de los atletas mediante diferentes estrategias de entrenamiento, como la exposición constante o intermitente a la altitud y el entrenamiento de intervalos de alta intensidad.
Objetivo: Revisar la literatura actual y describir los efectos sobre el organismo del entrenamiento de intervalos de alta intensidad en altitud simulada en sujetos sedentarios, físicamente activos y entrenados.
Resultados: el número de artículos revisados evidencia que, en hipoxia simulada en cámara hipobárica o normobárica (n=13) o máscara de simulación de altitud (n=1), todos utilizaron intensidades altas (n=13) a submáximas (n=1). Los participantes de las investigaciones fueron mujeres con obesidad sedentarias (n=3), hombres y mujeres físicamente activos (n=9) y sujetos entrenados (n=3). El tiempo de intervención de los estudios fue de 3 a 12 semanas, con una altitud simulada de 1824 a 4500 m.s.n.m. Se observaron efectos beneficiosos sobre la composición corporal, aptitud cardiorrespiratoria, aumentos en hemoglobina, eritropoyetina, consumo energético, fuerza máxima concéntrica e isométrica, fuerza absoluta y mejor tolerancia al ejercicio (percepción del esfuerzo).Conclusiones: La combinación de entrenamientos de intervalos de alta intensidad, combinado con una exposición en altitud simulada, puede evidenciar mejoras significativas en el rendimiento cardiorrespiratorio, así como en aspectos de composición corporal, lo que permitiría una mejor predisposición a intensidades más elevadas de actividad y ejercicio físico.
... El entrenamiento en altitud utiliza dos enfoques principales en busca de aumentos en el rendimiento deportivo: "vivir bajo y entrenar alto" [31,32] y "vivir alto-entrenar bajo" [33,34], con altitudes que pueden ir desde los 2300 hasta los 5700 m.s.n.m [35]. En altitud natural, el organismo puede presentar efectos adversos como el mal de montaña (a tan solo 2500 m.s.n.m). ...
Introducción: en la actualidad, los entrenadores buscan la manera de mejorar las capacidades físicas de los atletas mediante diferentes estrategias de entrenamiento, como la exposición constante o intermitente a la altitud y el entrenamiento de intervalos de alta intensidad.
Objetivo: Revisar la literatura actual y describir los efectos sobre el organismo del entrenamiento de intervalos de alta intensidad en altitud simulada en sujetos sedentarios, físicamente activos y entrenados.
Resultados: el número de artículos revisados evidencia que, en hipoxia simulada en cámara hipobárica o normobárica (n=13) o máscara de simulación de altitud (n=1), todos utilizaron intensidades altas (n=13) a submáximas (n=1). Los participantes de las investigaciones fueron mujeres con obesidad sedentarias (n=3), hombres y mujeres físicamente activos (n=9) y sujetos entrenados (n=3). El tiempo de intervención de los estudios fue de 3 a 12 semanas, con una altitud simulada de 1824 a 4500 m.s.n.m. Se observaron efectos beneficiosos sobre la composición corporal, aptitud cardiorrespiratoria, aumentos en hemoglobina, eritropoyetina, consumo energético, fuerza máxima concéntrica e isométrica, fuerza absoluta y mejor tolerancia al ejercicio (percepción del esfuerzo).
Conclusiones: La combinación de entrenamientos de intervalos de alta intensidad, combinado con una exposición en altitud simulada, puede evidenciar mejoras significativas en el rendimiento cardiorrespiratorio, así como en aspectos de composición corporal, lo que permitiría una mejor predisposición a intensidades más elevadas de actividad y ejercicio físico.
... Most commonly, athletes both live and train at moderate to high altitude (live high-train high, LHTH) or live at altitude and train at sea level (live high-train low, LHTL). Previous reports and reviews have shown increases in exercise performance, maximal oxygen consumption V O 2max , and hemoglobin mass after several weeks of LHTH and/or LHTL training (Bonetti & Hopkins, 2009;Millet et al., 2010;Robertson et al., 2010). ...
We investigated whether horses trained in moderate and mild hypoxia demonstrate greater improvement in performance and aerobic capacity compared to horses trained in normoxia and whether the acquired training effects are maintained after 2 weeks of post‐hypoxic training in normoxia. Seven untrained Thoroughbred horses completed 4 weeks (3 sessions/week) of three training protocols, consisting of 2‐min cantering at 95% maximal oxygen consumption under two hypoxic conditions (H16, FIO2 = 16%; H18, FIO2 = 18%) and in normoxia (N21, FIO2 = 21%), followed by 2 weeks of post‐hypoxic training in normoxia, using a randomized crossover study design with a 3‐month washout period. Incremental treadmill tests (IET) were conducted at week 0, 4, and 6. The effects of time and groups were analyzed using mixed models. Run time at IET increased in H16 and H18 compared to N21, while speed at was increased significantly only in H16. in all groups and cardiac output at exhaustion in H16 and H18 increased after 4 weeks of training, but were not significantly different between the three groups. In all groups, run time, , , , and lactate threshold did not decrease after 2 weeks of post‐hypoxic training in normoxia. These results suggest that 4 weeks of training in moderate (H16), but not mild (H18) hypoxia elicits greater improvements in performance and running economy than normoxic training and that these effects are maintained for 2 weeks of post‐hypoxic training in normoxia. The present study demonstrates that 4 weeks of training in moderate (FIO2 = 16%), but not mild hypoxia (FIO2 = 18%) was sufficient to elicit greater improvements in performance and running economy than normoxic training and that the effects of the hypoxic training were maintained over 2 weeks of post‐hypoxic training. Although trainers should monitor weight loss, our results can give a new insight into hypoxic training in horses and provide a new strategy for training programs in Thoroughbred racehorses.
... The use of altitude and intermittent hypoxic training have received substantial attention in the research literature, primarily due to their effectiveness in generating performance gains from very short exercise bouts [1][2][3]. Both simulated and genuine altitude training at moderate (2,000-3,000 m) to high elevations (3,000-4,500 m) are known to result in improvements in both central and peripheral adaptations that increase O 2 delivery and utilization [4][5][6], and that high-intensity interval training (HIIT) in hypoxia can be more effective than other training modes (e.g., intermittent hypoxic exposure during rest) [7]. ...
This study investigated the effect of high-intensity interval training (HIIT) cycling elevation training mask (ETM) in moderately trained participants on both aerobic (V̇O2max) and anaerobic power performance. Sixteen participants, five females (25.8 ± 7.6 years) and eleven males (22.2 ± 3.5 years) took part in this randomized controlled trial. Participants were assigned to the experimental group (ETM, n = 8 participants) wearing an ETM or the control group (CON, n = 8 participants) without the ETM. V̇O2max was determined during a standardized protocol using Cortex Metalyzer-3B on a cycle ergometer. Peak and average power were calculated a 30-second Wingate test. Participants completed 4-weeks (two sessions a week) of high-intensity cycle training. Each training session consisting of 4 separate bouts of 4-minutes of high-intensity cycling exercise. After the training period, ETM reported an increment in V̇O2max (effect size (d) = 1.19), peak power (d = 0.77), and average power (d = 0.76). CON reported an increment only in V̇O2max (d = 1.00). No-between group differences were found in any parameter (ANCOVA), therefore the two protocols should be considered equally effective. In conclusion, this study reported that both HIIT protocols significantly enhance V̇O2max in a very short training period (4 weeks).
... are probably neither of any physiological relevance-assuming a biological variability of~2.00% [6,[21][22][23][24]-, nor of practical relevance-assuming a smallest worthwhile change of about 0.3-1.2% [25][26][27]. ...
Purpose
To evaluate the intra-unit (RELINTRA) and inter-unit reliability (RELINTER) of two structurally identical units of the metabolic analyser K5 (COSMED, Rome, Italy) that allows to utilize either breath-by-breath (BBB) or dynamic mixing chamber (DMC) technology.
Methods
Identical flow- and gas-signals were transmitted to both K5s that always operated simultaneously either in BBB- or DMC-mode. To assess RELINTRA and RELINTER, a metabolic simulator was applied to simulate four graded levels of respiration. RELINTRA and RELINTER were expressed as typical error (TE%) and Intraclass Correlation Coefficient (ICC). To assess also inter-unit differences via natural respiratory signals, 12 male athletes performed one incremental bike step test each in BBB- and DMC-mode. Inter-unit differences within biological testing were expressed as percentages.
Results
In BBB, TE% of RELINTRA ranged 0.30–0.67 vs. RELINTER 0.16–1.39 and ICC ranged 0.57–1.00 vs. 0.09–1.00. In DMC, TE% of RELINTRA ranged 0.38–0.90 vs. RELINTER 0.03–0.86 and ICC ranged 0.22–1.00 vs. 0.52–1.00. Mean inter-unit differences ranged -2.30–2.20% (Cohen’s ds (ds) 0.13–1.52) for BBB- and -0.55–0.61% (ds 0.00–0.65) for DMC-mode, respectively. Inter-unit differences for and RER were significant (p < 0.05) at each step.
Conclusion
Two structurally identical K5-units demonstrated accurate RELINTRA with TE < 2.0% and similar RELINTER during metabolic simulation. During biological testing, inter-unit differences for and RER in BBB-mode were higher than 2% with partially large ES in BBB. Hence, the K5 should be allocated personally wherever possible. Otherwise, e.g. in multicenter studies, a decrease in total reliability needs to be considered especially when the BBB-mode is applied.
... This culminates in a model of how all these factors interact to create a unique response for each individual in response to a stimulus. This response is not stable, as the component factors themselves can be highly variable over time; just because an individual saw a performance improvement after one training programme does not guarantee the same improvement following the same programme once more (Robertson et al., 2010). This complex relationship is illustrated in figure 4. Figure 4 -A final model to explain inter-subject variation in exercise response. ...
Variation between individuals in response to a stimulus is a well-established phenomenon. This thesis discusses the drivers of this inter-individual response, identifying three major determinants; genetic, environmental, and epigenetic variation between individuals. Focusing on genetic variation, the thesis explores how this information may be useful in elite sport, aiming to answer the question “Is there utility to genetic information in elite sport?” The current literature was critically analysed, with a finding that the majority of exercise genomics research explains what has happened previously, as opposed to assisting practitioners in modifying athlete preparation and enhancing performance. An exploration of the potential ways in which genetic information may be useful in elite sport then follows, including that of inter- individual variation in response to caffeine supplementation, the use of genetic information to assist in reducing hamstring injuries, and whether genetic information may help identify future elite athletes. These themes are then explored via empirical work. In the first study, an internet-based questionnaire assessed the frequency of genetic testing in elite athletes, finding that around 10% had undertaken such a test. The second study determined that a panel of five genetic variants could predict the magnitude of improvements in Yo-Yo test improvements following a standardised training programme in youth soccer players. The third study demonstrated the effectiveness of a panel of seven genetic variants in predicting the magnitude of neuromuscular fatigue in youth soccer players. The fourth and final study recruited five current or former elite athletes, including an Olympic Champion, and created the most comprehensive Total Genotype Score in the published literature to date, to determine whether their scores deviated significantly from a control population of over 500 non-athletes. The genetic panels were unable to adequately discriminate the elite performers from non-athletes, suggesting that, at this time, genetic testing holds no utility in the identification of future elite performers. The wider utilisation of genetic information as a public health tool is discussed, and a framework for the implementation of genetic information in sport is also proposed. In summary, this thesis suggests that there is great potential for the use of genetic information to assist practitioners in the athlete management process in elite sport, and demonstrates the efficacy of some commercially available panels, whilst cautioning against the use of such information as a talent identification tool. The major limitation of the current thesis is the low sample sizes of many of the experimental chapters, a common issue in exercise genetics research. Future work should aim to further explore the implementation of genetic information in elite sporting environments.
... Tampoco es el VO 2 máximo -una medida sustituta de la función cardíaca máxima de acuerdo con esta teoría-un buen predictor de la capacidad atlética (Snell y Mitchell, 1984, Coetzer et al., 1993, Lucía et al., 1998 ni siquiera de los cambios en el rendimiento que ocurre con el entrenamiento (Jones, 1998(Jones, , 2006Legaz Arrese et al., 2007;Vollaard et al., 2009;Robertson et al., 2010). ...
This book is published by the University of Guadalajara and contents several different chapters of authors who are professors, researchers and postgraduate students on the sciences of Physical Education and Sports who belong to some educational and research institutions of Mexico and other countries. Each year is delivery a new book and this version is the correspondent of 2018.
... Immediately following the completion of the fourth submaximal stage (approximately equivalent to 20 km race walk speed), the gradient of the treadmill was increased by 0.5 degrees every 30 s, until the participant reached volitional exhaustion. Expired gas was collected and analyzed using a custom built indirect calorimetry system described previously [37], with the final 60 s of gas collection accepted as steady state and used to calculate RER and O 2 uptake during submaximal stages. VO 2 peak was taken as the highest 30 s value taken during the incremental portion of the test. ...
Introduction:
We repeated our study of intensified training on a ketogenic low-carbohydrate (CHO), high-fat diet (LCHF) in world-class endurance athletes, with further investigation of a "carryover" effect on performance after restoring CHO availability in comparison to high or periodised CHO diets.
Methods:
After Baseline testing (10,000 m IAAF-sanctioned race, aerobic capacity and submaximal walking economy) elite male and female race walkers undertook 25 d supervised training and repeat testing (Adapt) on energy-matched diets: High CHO availability (8.6 g∙kg-1∙d-1 CHO, 2.1 g∙kg-1∙d-1 protein; 1.2 g∙kg-1∙d-1 fat) including CHO before/during/after workouts (HCHO, n = 8): similar macronutrient intake periodised within/between days to manipulate low and high CHO availability at various workouts (PCHO, n = 8); and LCHF (<50 g∙d-1 CHO; 78% energy as fat; 2.1 g∙kg-1∙d-1 protein; n = 10). After Adapt, all athletes resumed HCHO for 2.5 wk before a cohort (n = 19) completed a 20 km race.
Results:
All groups increased VO2peak (ml∙kg-1∙min-1) at Adapt (p = 0.02, 95%CI: [0.35-2.74]). LCHF markedly increased whole-body fat oxidation (from 0.6 g∙min-1 to 1.3 g∙min-1), but also the oxygen cost of walking at race-relevant velocities. Differences in 10,000 m performance were clear and meaningful: HCHO improved by 4.8% or 134 s (95% CI: [207 to 62 s]; p < 0.001), with a trend for a faster time (2.2%, 61 s [-18 to +144 s]; p = 0.09) in PCHO. LCHF were slower by 2.3%, -86 s ([-18 to -144 s]; p < 0.001), with no evidence of superior "rebound" performance over 20 km after 2.5 wk of HCHO restoration and taper.
Conclusion:
Our previous findings of impaired exercise economy and performance of sustained high-intensity race walking following keto-adaptation in elite competitors were repeated. Furthermore, there was no detectable benefit from undertaking an LCHF intervention as a periodised strategy before a 2.5-wk race preparation/taper with high CHO availability.
Trial registration:
Australia New Zealand Clinical Trial Registry: ACTRN12619000794101.
... 11 Although not unanimous, the majority of literature points to improved sea-level performance or haematological changes following LHTL. For example, elite endurance athletes have improved running economy, 12 and haemoglobin mass (Hb mass ), 13 An increased Hb mass appears beneficial for performance in repeated aerobic efforts. In elite female cyclists following LHTL, Hb mass was clamped in one group and free to adapt in a second. ...
... La mayoría de la literatura apunta a una mejora en el rendimiento del nivel del mar o cambios hematológicos después de LHTL ( Bonetti et al., 2006). Tal y como la mejora de la economía de carrera y de los atletas de resistencia de élite ( Saunders et al., 2004) y la masa de la hemoglobina ( Robertson et al., 2010) en comparación con los deportistas que viven y entrenan a nivel del mar. Live-high train-low produce ganancias valiosas en el rendimiento para atletas de resistencia, pero los beneficios de la adaptación a varias formas de altitud artificial son menos claros ( Bonetti et al., 2006). ...
... Robach et al. (2006) reported that LHTL (training at 1,200 m while residing at 2,500 or 3,000 m) for 13 days had a positive effect on the red blood cell volume in swimmers; however, this hematological response was not associated with a clear concomitant improvement in aerobic performance. Similarly, Robertson et al. (2010) concluded that 21 days of LHTL (training below 500 m while residing at 3,000 m) can induce a reproducible mean improvement in the Hbmass and VO 2 max in elite athletes; however, this enhanced physiological capacity did not translate in improved 4-5-km time trial performance. ...
Living high-training low (LHTL) is performed by competitive athletes expecting to improve their performance in competitions at sea level. However, the beneficial effects of LHTL remain controversial. We sought to investigate whether 21 days of LHTL performed at a 3,000 m simulated altitude (fraction of inspired oxygen [FIO2]=14.5%) and at sea level can improve hematologi-cal parameters, exercise economy and metabolism, hemodynamic function, and exercise performance compared with living low-training low (LLTL) among competitive athletes. All participants (age = 23.5 ± 2.1 years, maximal oxygen consumption [VO2max] = 55.6 ± 2.5 mLꞏkg-1 ꞏmin-1 , 3,000 m time trial perfor-mance=583.7 ± 22.9 seconds) were randomly assigned to undergo LHTL (n = 12) or LLTL (n = 12) and evaluated before and after the 21 days of intervention. During the 21-day intervention period, the weekly routine for all athletes included 6-day training and 1-day rest. The daily training programs consisted of >4 hours of various exercise programs (i.e., jogging, high-speed running, interval running, and 3,000 m or 5,000-m time trial). The LHTL group resided in a simulated environmental chamber (FIO2 = 14.5%) for >12 hours per day and the LLTL group at sea level under comfortable conditions. The hematological parameters showed no significant interaction. However, LHTL yielded more improved exercise economy, metabolic parameters (oxygen con-sumption=-152.7 vs 32.4 mLꞏkg-1 ꞏ30min-1 , η 2 = 0.457, p = 0.000; tissue oxygenation index=6.18 vs .66%, η 2 = 0.250, p = 0.013), and hemodynamic function (heart rate =-234.5 vs-49.7 beatsꞏ30min-1 , η 2 = 0.172, p = 0.044; stroke volume = 136.4 vs-120.5 mL/30 min, η 2 = 0.191, p = 0.033) during 30 minutes of submaximal cycle ergometer exercise corresponding to 80% maximal heart rate before training than did LLTL. Regarding exercise performance, LHTL also yielded more improved VO2max (5.40 vs 2.35 mLꞏkg-1 ꞏmin-1 , η 2 = 0.527, p = 0.000) and 3,000 m time trial performance (-34.0 vs-19.5 seconds, η 2 = 0.527, p = 0.000) than did LLTL. These results indicate that compared with LLTL, LHTL can have favorable effects on exercise performance by improving exercise economy and hemodynamic function in competitive runners.
... It has been suggested that longer than 8 weeks is required between altitude training stints to maximize the training afterward (Robertson et al., 2010). A longer time between altitude exposures also ensures that athletes are not excessively fatigued going into a subsequent altitude training camp, training phase, or competition. ...
High-level athletes are always looking at ways to maximize training adaptations for competition performance, and using altered environmental conditions to achieve this outcome has become increasingly popular by elite athletes. Furthermore, a series of potential nutrition and hydration interventions may also optimize the adaptation to altered environments. Altitude training was first used to prepare for competition at altitude, and it still is today; however, more often now, elite athletes embark on a series of altitude training camps to try to improve sea-level performance. Similarly, the use of heat acclimation/acclimatization to optimize performance in hot/humid environmental conditions is a common practice by high-level athletes and is well supported in the scientific literature. More recently, the use of heat training to improve exercise capacity in temperate environments has been investigated and appears to have positive outcomes. This consensus statement will detail the use of both heat and altitude training interventions to optimize performance capacities in elite athletes in both normal environmental conditions and extreme conditions (hot and/or high), with a focus on the importance of nutritional strategies required in these extreme environmental conditions to maximize adaptations conducive to competitive performance enhancement.
... Пробу берут непосредственно до исследования, на шестой и восьмой минутах после процедуры возвратного дыхания. По данным ряда публикаций при корректном выполнение всех тестовых процедур ошибка данного метода составляет 1,1-2% [13]. Таким образом «оптимизированный метод» определения t-Hb-mass и ОЦК является наиболее удобным и доступным из всех существующих на сегодняшний день методов, позволяет производить регулярные измерения даже в условиях учебно- ...
Haemoglobin is one of the crucial important proteins in oxygen transport that contains in the red blood cells and it level is important for endurance exercise. With the standart biochemistry test sometimes is not possible to measure the amount of haemoglobin and precise it changes. Total haemoglobin mass (tHb-mass) refers to the total amount of Hb within the body, irrespective of compartmental fluid volumes. There is a strong relationship between tHb-mass and maximal oxygen uptake. A 1 g increase in tHb-mass results in an increase in maximal oxygen uptake of approximately 4 ml/min. This fact shoes that tHb-mass may also is closely related to endurance performance. THb-mass and blood volume is useful to measure to understand current level of performance, individual response to hypoxia, talent identification in young athletes and for detect blood doping. The aim of the present review was to discuss advantages of new method and elucidate the main points how this method can be applied to routine training practice.
... Interestingly, 4500-m time trial running in elite middle-and long-distance runners is substantially improved (>75% likely to have a positive effect and <5% likely to have a negative effect) (20) and so is 1000-m running (effect size = 0.56) and possibly 2000-m running (25%-75% likelihood, effect size = 0.22) in semi-professional footballers (23) after 19-21 d of normobaric LHTL at 3000 m for 12-14 h·d −1 . Albeit these results are reported relative to a control group, the results were interpreted by a magnitude-based inferences approach (38). ...
The novel hypothesis that "Live High-Train Low" (LHTL) does not improve sport-specific exercise performance (e.g., time trial) is discussed. Indeed, many studies demonstrate improved performance after LHTL but unfortunately control groups are often lacking, leaving open the possibility of training camp effects. Importantly, when control groups, blinding procedures and strict scientific evaluation criteria are applied, LHTL has no detectable effect on performance.
... This culminates in a model illustrating how these factors interact, creating a unique outcome for each individual in response to a stimulus. This response is not stable, as the component factors themselves can be highly variable over time; just because an individual saw a performance improvement after one training programme doesn't guarantee the same improvement following the same programme once more [207]. Fig. (4) illustrates this complex relationship. ...
Abstract:
Background:
Traditional exercise prescription is based on the assumption that exercise adaptation is predictable and standardised across individuals. However, evidence has emerged in the past two decades demonstrating that large inter-individual variation exists regarding the magnitude and direction of adaption following exercise.
Objective:
The aim of this paper was to discuss the key factors influencing this personalized response to exercise in a narrative review format.
Findings:
Genetic variation contributes significantly to the personalized training response, with specific polymorphisms associated with differences in exercise adaptation. These polymorphisms exist in a number of pathways controlling exercise adaptation. Environmental factors such as nutrition, psycho-emotional response, individual history and training programme design also modify
the inter-individual adaptation following training. Within the emerging field of epigenetics, DNA methylation, histone modifications
and non-coding RNA allow environmental and lifestyle factors to impact genetic expression. These epigenetic mechanisms are themselves modified by genetic and non-genetic factors, illustrating the complex interplay between variables in determining the adaptive response. Given that genetic factors are such a fundamental modulator of the inter-individual response to exercise, genetic
testing may provide a useful and affordable addition to those looking to maximise exercise adaption, including elite athletes. However, there are ethical issues regarding the use of genetic tests, and further work is needed to provide evidence based guidelines
for their use.
Conclusion:
There is considerable inter-individual variation in the adaptive response to exercise. Genetic assessments may provide an additional layer of information allowing personalization of training programmes to an individual’s unique biology.
... r 2 = 0.28) (Parisotto et al., 2000;Saunders et al., 2013;Schmidt & Prommer, 2010) emphasising that VO 2max is a complex parameter that is not exclusively determined by the red cell mass (Levine, 2008). The present study underpins the complex interaction among altitude acclimatization effects (such as Hb mass among others), altitude and SL training effects, VO 2max , and performance in events of different sports and different durations/intensities requiring widely divergent metabolic demands (Chapman et al., 2014;Friedmann, Frese, Menold, Kauper, et al., 2005;Gore et al., 1998;Robertson, Saunders, et al., 2010;Wachsmuth et al., 2012). Despite failing to demonstrate an increase in tHb mass or VO 2max , the swimmers in the Hi-HiLo group clearly improved performance more than the altitude controls. ...
Training at natural altitude failed so far to prove useful for the enhancement of sea level (SL) performance in swimmers. This controlled nonrandomized four parallel groups trial examined the effects of four interventions: living high-training high for 3 or 4 weeks (Hi-Hi3, Hi-Hi), living high-training high/low (Hi-HiLo), and living and training at SL for 4 weeks (Lo-Lo). From 65 elite swimmers, 54 met all inclusion criteria and completed SL time trials over 100 (sprinters) or 200 m (non-sprinters) at best personal stroke (TT100/TT200). VO 2max was measured on an incremental 4x200-m front crawl test. Training load was estimated using TRIMP and session RPE. Initial performance and measures (PRE) were repeated immediately after the camp (POST) and once weekly on return to SL for 4 weeks. Intervention effects were analysed using mixed linear modelling. TT100 or TT200 improved by ∼3.5% regardless of living or training at SL or at altitude, but Hi-HiLo improved more two (5.3±1.6%) and four weeks (6.3±1.9%) after the intervention. There were no changes in VO 2max in any of the groups. tHb mass increased in Hi-Hi (6.2±2.6%) and Hi-Hi3 (3.8±5.6%), whereas no changes were noted in Hi-HiLo (1.3±4.3%). Hi-HiLo is an effective strategy to enhance performance in elite swimmers. This improvement was not linked to changes in VO 2max or tHb mass .
... During their first visit, participants completed aVO 2max test to assess maximal aerobic power. The test consisted of 3 × 4 min periods of incremental running before speed was maintained and gradient increased by 1% each minute until volitional exhaustion (Robertson et al., 2010). Participants then returned for a separate familiarization session, involving a 5 min warm-up at 100 W on a cycle ergometer (Velotron, Seattle, USA) followed by four maximal 4 s sprints, each separated by 14 s of passive recovery, on the non-motorized treadmill (Woodway Force, Waukesha, WI, USA). ...
Purpose: To quantify the effect of acute hypoxia on muscle oxygenation and power during simulated team-sport running.
Methods: Seven individuals performed repeated and single sprint efforts, embedded in a simulated team-sport running protocol, on a non-motorized treadmill in normoxia (sea-level), and acute normobaric hypoxia (simulated altitudes of 2,000 and 3,000 m). Mean and peak power was quantified during all sprints and repeated sprints. Mean total work, heart rate, blood oxygen saturation, and quadriceps muscle deoxyhaemoglobin concentration (assessed via near-infrared spectroscopy) were measured over the entire protocol. A linear mixed model was used to estimate performance and physiological effects across each half of the protocol. Changes were expressed in standardized units for assessment of magnitude. Uncertainty in the changes was expressed as a 90% confidence interval and interpreted via non-clinical magnitude-based inference.
Results: Mean total work was reduced at 2,000 m (−10%, 90% confidence limits ±6%) and 3,000 m (−15%, ±5%) compared with sea-level. Mean heart rate was reduced at 3,000 m compared with 2,000 m (−3, ±3 min⁻¹) and sea-level (−3, ±3 min⁻¹). Blood oxygen saturation was lower at 2,000 m (−8, ±3%) and 3,000 m (−15, ±2%) compared with sea-level. Sprint mean power across the entire protocol was reduced at 3,000 m compared with 2,000 m (−12%, ±3%) and sea-level (−14%, ±4%). In the second half of the protocol, sprint mean power was reduced at 3,000 m compared to 2,000 m (−6%, ±4%). Sprint mean peak power across the entire protocol was lowered at 2,000 m (−10%, ±6%) and 3,000 m (−16%, ±6%) compared with sea-level. During repeated sprints, mean peak power was lower at 2,000 m (−8%, ±7%) and 3,000 m (−8%, ±7%) compared with sea-level. In the second half of the protocol, repeated sprint mean power was reduced at 3,000 m compared to 2,000 m (−7%, ±5%) and sea-level (−9%, ±5%). Quadriceps muscle deoxyhaemoglobin concentration was lowered at 3,000 m compared to 2,000 m (−10, ±12%) and sea-level (−11, ±12%).
Conclusions: Simulated team-sport running is impaired at 3,000 m compared to 2,000 m and sea-level, likely due to a higher muscle deoxygenation.
... Heart rate (HR) was measured continuously during the test (Polar Heart Rate Monitor, Polar Electro, Kempele, Finland). Expired gas was collected and analysed using a custom-built indirect calorimetry system described previously (Robertson et al. 2010), with the final 60 s of gas collection accepted as steady state and used to calculate RER and O 2 uptake. On completion of the final submaximal walking stage, subjects rested for 5 min before completing a ramp (speed and then gradient) test to volitional fatigue. ...
Key points
Three weeks of intensified training and mild energy deficit in elite race walkers increases peak aerobic capacity independent of dietary support.
Adaptation to a ketogenic low carbohydrate, high fat (LCHF) diet markedly increases rates of whole‐body fat oxidation during exercise in race walkers over a range of exercise intensities.
The increased rates of fat oxidation result in reduced economy (increased oxygen demand for a given speed) at velocities that translate to real‐life race performance in elite race walkers.
In contrast to training with diets providing chronic or periodised high carbohydrate availability, adaptation to an LCHF diet impairs performance in elite endurance athletes despite a significant improvement in peak aerobic capacity.
Abstract
We investigated the effects of adaptation to a ketogenic low carbohydrate (CHO), high fat diet (LCHF) during 3 weeks of intensified training on metabolism and performance of world‐class endurance athletes. We controlled three isoenergetic diets in elite race walkers: high CHO availability (g kg⁻¹ day⁻¹: 8.6 CHO, 2.1 protein, 1.2 fat) consumed before, during and after training (HCHO, n = 9); identical macronutrient intake, periodised within or between days to alternate between low and high CHO availability (PCHO, n = 10); LCHF (< 50 g day⁻¹ CHO; 78% energy as fat; 2.1 g kg⁻¹ day⁻¹ protein; LCHF, n = 10). Post‐intervention, V˙O2 peak during race walking increased in all groups (P < 0.001, 90% CI: 2.55, 5.20%). LCHF was associated with markedly increased rates of whole‐body fat oxidation, attaining peak rates of 1.57 ± 0.32 g min⁻¹ during 2 h of walking at ∼80% V˙O2 peak . However, LCHF also increased the oxygen (O2) cost of race walking at velocities relevant to real‐life race performance: O2 uptake (expressed as a percentage of new V˙O2 peak ) at a speed approximating 20 km race pace was reduced in HCHO and PCHO (90% CI: −7.047, −2.55 and −5.18, −0.86, respectively), but was maintained at pre‐intervention levels in LCHF. HCHO and PCHO groups improved times for 10 km race walk: 6.6% (90% CI: 4.1, 9.1%) and 5.3% (3.4, 7.2%), with no improvement (−1.6% (−8.5, 5.3%)) for the LCHF group. In contrast to training with diets providing chronic or periodised high‐CHO availability, and despite a significant improvement in V˙O2 peak , adaptation to the topical LCHF diet negated performance benefits in elite endurance athletes, in part due to reduced exercise economy.
... ) y/o hematológicas(Bonetti y Hopkins, 2009, Chapman, Karlsen, Resaland, Ge, Harber, Witkowski, Stray-Gundersen y Levine, 2014, Garvican-Lewis, Halliday, Abbiss, Saunders y Gore, 2015, Saugy, y col., 2014, Wehrlin y Marti, 2006. Por el contrario, los resultados positivos (+0.6% y +1.4% para los atletas de élite y no élite) han sido menos frecuentes en condiciones de hipoxia normobárica(Bonetti y Hopkins, 2009, Clark, Quod, Clark, Martin, Saunders y Gore, 2009, Robach, Schmitt, Brugniaux, Roels, Millet, Hellard, Nicolet, Duvallet, Fouillot, Moutereau, Lasne, Pialoux, Olsen y Richalet, 2006, Robertson, Saunders, Pyne, Aughey, Anson y Gore, 2010. ...
Entre los diferentes métodos de entrenamiento en altitud, el "entrenamiento hipóxico intermitente" (IHT) – método en el cual los atletas viven al nivel del mar pero se entrenan en condiciones de hipoxia – ha ganado una popularidad sin precedentes. Un análisis exhaustivo de los estudios que incluyen IHT muestra los beneficios sorprendentemente pobres para la mejora del rendimiento al nivel del mar, en comparación con el mismo entrenamiento realizado en normoxia. A pesar de las adaptaciones moleculares positivas observadas después de varias modalidades IHT, las características de estímulo del entrenamiento óptimo en hipoxia son todavía confusas y su traducción funcional en una mejora de rendimiento general es mínima. Para superar algunas limitaciones inherentes al IHT (carga de trabajo inferior debido a la hipoxia), estudios recientes han investigado un nuevo método, llamado RSH, de entrenamiento basado en la repetición de sprints con recuperaciones incompletas en hipoxia. Además, el creciente interés científico acerca de la aplicación práctica del entrenamiento hipóxico legitima el desarrollo de tecnologías innovadoras que sirven a los atletas de un deporte específico. Los objetivos de esta revisión son triples. Primero, analizar los resultados de los estudios que implican ejercicios de alta intensidad realizados en hipoxia para mejorar el rendimiento al nivel del mar diferenciando IHT y RSH. Segundo, discutir los posibles mecanismos que sustentan su eficacia y sus limitaciones inherentes. Tercero, presentar los beneficios potenciales del uso de innovaciones tecnológicas que indudablemente contribuirán a mejorar la comprensión de las adaptaciones fisiológicas inducidas por hipoxia mediante la realización de investigaciones pertinentes con un ajuste "ecológico" específico.
**
Among the different altitude training methods, intermittent hypoxic training (IHT); i.e., a method where athletes live at or near sea level but train under hypoxic conditions, has gained unprecedented popularity. A thorough analysis of studies including IHT, however, leads to strikingly poor benefits for sea-level performance improvement, compared to the same training method performed in normoxia. Despite positive molecular adaptations observed after various IHT modalities, the characteristics of optimal training stimulus in hypoxia are still unclear and their functional translation in term of whole-body performance enhancement is minimal. To overcome some of the inherent limitations of IHT (lower workload due to hypoxia), recent studies have successfully investigated a new training method based on the repetition of short sprints with incomplete recoveries in hypoxia; named RSH. Additionally, the growing scientific interest on the practical application of hypoxic training legitimizes the development of innovative technologies serving athletes in a sport-specific setting. The aims of the present review are therefore threefold. First, to critically analyze the results of the studies involving high-intensity exercises performed in hypoxia for sea-level performance enhancement by differentiating IHT and RSH. Second, to discuss the potential mechanisms underpinning their effectiveness and their inherent limitations. Third, to present the potentials benefits of using new technological innovation (i.e., the mobile inflatable simulated hypoxic system) which will undoubtedly contribute to the understanding advancement of hypoxia-induced physiological adaptations by conducting relevant research in the most sport-specific ecological test setting.
... The live high-train low (LHTL) approach is based on the 1997 Levine & Stray-Gundersen study (Levine & Stray-Gundersen, 1997) in which they demonstrated greater improvements in endurance performance in the LHTL compared with the matched control group. The fact that subsequent studies using normobaric hypoxia repeatedly failed to show such positive outcome, in particular in highly trained individuals (Robertson et al. 2010;Siebenmann et al. 2012), raised question about the overall efficacy of LHTL but at the same time reinforced the idea that LHTL using natural altitude remained the best approach for elite athletes (Bonetti & Hopkins, 2009). Unfortunately, most subsequent LHTL studies using natural altitude did not include a matched sea-level control group (Stray-Gundersen et al. 2001;Wehrlin et al. 2006;Chapman et al. 2014;Saugy et al. 2014) and therefore cannot be used to confirm or discard the rationale for LHTL. ...
What is the topic of this review? The aim is to evaluate the effectiveness of various altitude training strategies as investigated within the last few years. What advances does it highlight? Based on the available literature, the foundation to recommend altitude training to athletes is weak. Athletes may use one of the various altitude training strategies to improve exercise performance. The scientific support for such strategies is, however, not as sound as one would perhaps imagine. The question addressed in this review is whether altitude training should be recommended to elite athletes or not. © 2016 The Authors. Experimental Physiology
... When the typical error of measurement in these studies is considered, it is clear that such studies are generally underpowered for statistical purposes. It has also been noted in these trials that endurance may be altered by placebo or training camp effects, fatigue or motivation [47,48]. Table 3 summarises the three main models of altitude training, their rationale, and associated positive and negative effects. ...
High altitude training is regarded as an integral component of modern athletic preparation, especially for endurance sports such as middle and long distance running. It has rapidly achieved popularity among elite endurance athletes and their coaches. Increased hypoxic stress at altitude facilitates key physiological adaptations within the athlete, which in turn may lead to improvements in sea-level athletic performance. Despite much research in this area to date, the exact mechanisms which underlie such improvements remain to be fully elucidated. This review describes the current understanding of physiological adaptation to high altitude training and its implications for athletic performance. It also discusses the rationale and main effects of different training models currently employed to maximise performance. Athletes who travel to altitude for training purposes are at risk of suffering the detrimental effects of altitude. Altitude illness, weight loss, immune suppression and sleep disturbance may serve to limit athletic performance. This review provides an overview of potential problems which an athlete may experience at altitude, and offers specific training recommendations so that these detrimental effects are minimised.
... Of interest is the observed intra- 276 individual variability between successive years, in line with a previous case study (Garvican 277 et al., 2007). This inter-or intra-subjects variability between the two phases raises questions 278 about the physiological basis of highly variables findings from previous published LHTL 279 studies (Pialoux et al., 2009;Robertson et al., 2010a;Nordsborg et al., 2012;Robach et al., 280 2012;Siebenmann et al., 2012;Garvican-Lewis et al., 2013). With small effects and sample 281 sizes, added to the large among of confounding factors (i.e. ...
Purpose:
We investigated the changes in physiological and performance parameters after a Live High-Train Low (LHTL) altitude camp in normobaric (NH) or hypobaric hypoxia (HH) to reproduce the actual training practices of endurance athletes using a crossover-designed study.
Methods:
Well-trained triathletes (n = 16) were split into two groups and completed two 18-day LTHL camps during which they trained at 1100-1200 m and lived at 2250 m (P i O2 = 111.9 ± 0.6 vs. 111.6 ± 0.6 mmHg) under NH (hypoxic chamber; FiO2 18.05 ± 0.03%) or HH (real altitude; barometric pressure 580.2 ± 2.9 mmHg) conditions. The subjects completed the NH and HH camps with a 1-year washout period. Measurements and protocol were identical for both phases of the crossover study. Oxygen saturation (S p O2) was constantly recorded nightly. P i O2 and training loads were matched daily. Blood samples and VO2max were measured before (Pre-) and 1 day after (Post-1) LHTL. A 3-km running-test was performed near sea level before and 1, 7, and 21 days after training camps.
Results:
Total hypoxic exposure was lower for NH than for HH during LHTL (230 vs. 310 h; P < 0.001). Nocturnal S p O2 was higher in NH than in HH (92.4 ± 1.2 vs. 91.3 ± 1.0%, P < 0.001). VO2max increased to the same extent for NH and HH (4.9 ± 5.6 vs. 3.2 ± 5.1%). No difference was found in hematological parameters. The 3-km run time was significantly faster in both conditions 21 days after LHTL (4.5 ± 5.0 vs. 6.2 ± 6.4% for NH and HH), and no difference between conditions was found at any time.
Conclusion:
Increases in VO2max and performance enhancement were similar between NH and HH conditions.
... That heat acclimatization does not impair performance in cool conditions and may be a clever strategy for athletes if the competitive conditions are potentially hot does not allow physiologists to conclude that it improves performance in cool settings. Lessons from altitude training taught us that the 'responder?non-responder issue' could not be supported by robust responses during repeated exposures (Robertson et al. 2010), and double blinded, placebo controlled studies (Siebenmann et al. 2012; Robach et al. 2014) fail to support the 1% performance enhancement concluded from meta-analysis of altitude training studies (Bonetti & Hopkins, 2009). Although, heat acclimatization studies in truly elite athletes are lacking it is difficult to see that they should respond differently from the endurance trained athletes in recent studies (Karlsen et al. 2015; Keiser et al. 2015) as plasma volume expansion is ineffective when subjects possess high plasma volumes and a cardiovascular system adapted to several years of training (see Nybo & Lundby, 2015). ...
Background:
Altitude training is often regarded as an indispensable tool for the success of elite endurance athletes. Historically, altitude training emerged as a key strategy to prepare for the 1968 Olympics, held at 2300 m in Mexico City, and was limited to the "Live High-Train High" method for endurance athletes aiming for performance gains through improved oxygen transport. This "classical" intervention was modified in 1997 by the "Live High-Train Low" (LHTL) model wherein athletes supplemented acclimatization to chronic hypoxia with high-intensity training at low altitude.
Purpose:
This review discusses important considerations for successful implementation of LHTL camps in elite athletes based on experiences, both published and unpublished, of the authors.
Approach:
The originality of our approach is to discuss 10 key "lessons learned," since the seminal work by Levine and Stray-Gundersen was published in 1997, and focusing on (1) optimal dose, (2) individual responses, (3) iron status, (4) training-load monitoring, (5) wellness and well-being monitoring, (6) timing of the intervention, (7) use of natural versus simulated hypoxia, (8) robustness of adaptative mechanisms versus performance benefits, (9) application for a broad range of athletes, and (10) combination of methods. Successful LHTL strategies implemented by Team USA athletes for podium performance at Olympic Games and/or World Championships are presented.
Conclusions:
The evolution of the LHTL model represents an essential framework for sport science, in which field-driven questions about performance led to critical scientific investigation and subsequent practical implementation of a unique approach to altitude training.
Physiatrists are uniquely qualified to serve as sports medicine physicians and care for the recreational and competitive athlete as well as those who exercise for health-related benefits. Physiatrists are trained extensively in musculoskeletal medicine and injury, functional rehabilitation, and coordinating and leading a team of professionals to optimize care of patients. The sports medicine team includes the athlete, his or her family, specialty and primary care physicians, athletic trainers, physical and massage therapists, chiropractors, dieticians, psychologists, and coaches. Physiatrists are also skilled in prehabilitation, or preventive rehabilitation, which is an important aspect of care for any athlete involved in routine physical training.
Exercise physiology, emergency medical care, and more routine medical care are also important to any well-rounded sports medicine physician. This chapter covers the breadth of sports medicine for the physiatrist, including the general role and medicolegal aspects of being a team physician, sporting event administration with a particular focus on emergency preparedness, athletic conditioning and training principles, injury prevention and functional rehabilitation, biomechanics of sports, pharmacology in sports, emergency assessment and care of the athlete, common medical and neurologic conditions in athletes, and a review of specific populations of athletes and their common ailments, including a special focus on athletes with disabilities and adaptive sports medicine. This chapter is not intended to be a musculoskeletal medicine chapter because other chapters in this text cover in-depth musculoskeletal issues that overlap with the musculoskeletal injuries seen in athletes.
The present study investigated if athletes can be classified as responders or non‐responders based on their individual change in total hemoglobin mass (tHb‐mass) following altitude training while also identifying the potential factors that may affect responsiveness to altitude exposure. Measurements were completed with 59 elite endurance athletes who participated in national team altitude training camps. Fifteen athletes participated the altitude training camp at least twice. Total Hb‐mass using a CO rebreathing method and other blood markers were measured before and after a total of 82 altitude training camps (1350‐2500 m) in 59 athletes. In 46 (56 %) altitude training camps tHb‐mass increased. The amount of positive responses increased to 65 % when only camps above 2000 m were considered. From the fifteen athletes who participated in altitude training camps at least twice, 27 % always had positive tHb‐mass responses, 13 % only negative responses and 60 % both positive and negative responses. Logistic regression analysis showed that altitude was the most significant factor explaining positive tHb‐mass response. Furthermore, male athletes had greater tHb‐mass response than female athletes. In endurance athletes, tHb‐mass is likely to increase after altitude training given that hypoxic stimulus is appropriate. However, great inter‐ and intraindividual variability in tHb‐mass response does not support classification of an athlete permanently as a responder or non‐responder. This variability warrants efforts to control numerous factors affecting an athlete’s response to each altitude training camp.
Introduction: Adaptation to attitude is a complementary exercise to increase athletes' fitness and physiological performance. The present study investigated the effect of high intensity interval training at the hypobaric hypoxia conditions on weight changes and endurance performance test in rats following a three-weeks tapering period.
Materials and Methods: In this experimental study, 25 males four weeks age Wistar rats with average weight (81±9 g) were randomly divided in two groups, exercise and control. Exercise group after the end of 6 weeks high intensity interval training (HIIT) (5 days per week, 30 minutes per session and at a speed of 15 to 70 meters per minute) divided into HIIT, Hypoxia, Taper and hypoxia with taper groups for 3 weeks. Weight changes and Endurance Test Performance were evaluated on the end of weeks. Analyzed is done with one-way ANOVA and TUKEY test at p<0.05.
Results: The results showed that there are significant differences (p≤0.05) in fatigue times in hypoxic and taper-hypoxia groups with interval training group, respectively, 30.59 and 37.08. (p=0.001). Also, taper-hypoxic group showed the best performance to compare HIIT and control groups, that was increase significantly (p=0.001).
Conclusion: It seems that use of hypoxic training program and taper techniques have a positive effect on endurance performance and time to exhaustion however the use taper with hypoxia condition need to be evaluated in combination.
The effects of iron stores and supplementation on erythropoietic responses to moderate altitude in endurance athletes were examined. In a retrospective study, red cell compartment volume (RCV) responses to 4-weeks at 2,500m were assessed in athletes with low (n=9, ≤20 and ≤30 ng·ml ⁻¹ for women and men, respectively) and normal (n=10) serum ferritin levels ([Ferritin]) without iron supplementation. In a subsequent prospective study, the same responses were assessed in athletes (n=26) with a protocol designed to provide sufficient iron before and during identical altitude exposure. The responses to a 4-week training camp at sea-level were assessed in another athletes (n=13) as controls. RCV and maximal oxygen uptake (Vo 2max ) were determined at sea-level before and after intervention. In the retrospective study, athletes with low [Ferritin] did not increase RCV (27.0±2.9 to 27.5±3.8 ml·kg ⁻¹ , mean±SD, P=0.65) nor Vo 2max (60.2±7.2 to 62.2±7.5 ml·kg ⁻¹ ·min ⁻¹ , P=0.23) after 4-weeks at altitude, whereas athletes with normal [Ferritin] increased both (RCV: 27.3±3.1 to 29.8±2.4 ml·kg ⁻¹ , P=0.002; Vo 2max : 62.0±3.1 to 66.2±3.7 ml·kg ⁻¹ ·min ⁻¹ , P=0.003). In the prospective study, iron supplementation normalized low [Ferritin] observed in athletes exposed to altitude (n=14) and sea-level (n=6) before the altitude/sea-level camp, and maintained [Ferritin] within normal range in all athletes while the camp. RCV and Vo 2max increased in the altitude group, but remained unchanged in the sea-level group. Finally, the increase in RCV correlated with the increase in Vo 2max (r=0.368, 95% CI: 0.059 to 0.612, P=0.022). Thus, iron deficiency in athletes restrains erythropoiesis to altitude exposure and may preclude improvement in sea-level athletic performance.
Live high – train low (LHTL) using hypobaric hypoxia was previously found to improve sea-level endurance performance in well-trained individuals, however confirmatory controlled data in athletes are lacking. Here we test the hypothesis that natural-altitude LHTL improves aerobic performance in cross-country skiers, in conjunction with expansion of total hemoglobin mass (Hbmass, carbon-monoxide rebreathing technique) promoted by accelerated erythropoiesis. Following duplicate baseline measurements at sea level over the course of two weeks, nineteen Norwegian cross-country skiers (three women, sixteen men, age 20±2 yr, maximal oxygen uptake (VO2max) 69±5 ml.min⁻¹.kg⁻¹) were assigned to 26 consecutive nights spent either at low (1035m, Control, n=8) or moderate altitude (2207m, daily exposure 16.7±0.5 hours, LHTL, n=11). All athletes trained together daily at a common location ranging from 550-1500m (21.2% of training time at 550m, 44.2% at 550-800m, 16.6% at 800-1100m, 18.0% at 1100-1500m). Three test sessions at sea level were performed over the first three weeks after intervention. Despite the demonstration of nocturnal hypoxemia at moderate altitude (pulse oximetry), LHTL had no specific effect on serum erythropoietin, reticulocytes, Hbmass, VO2max or 3000-m running performance. Also LHTL had no specific effect on i) running economy (VO2 assessed during steady-state submaximal exercise), ii) respiratory capacities or efficiency of the skeletal muscle (biopsy), and iii) diffusing capacity of the lung. The present study, showing similar physiological responses and performance improvements in the two groups following intervention, suggests that in young cross-country skiers, improvements in sea-level aerobic performance associated with LHTL may not be due to moderate altitude acclimatization.
Purpose:
To compare individual hemoglobin mass (Hbmass) changes following a live high-train low (LHTL) altitude training camp under either normobaric hypoxia (NH) or hypobaric hypoxia (HH) conditions in endurance athletes.
Methods:
In a crossover design with a one-year washout, 15 male triathletes randomly performed two 18-d LHTL training camps in either HH or NH. All athletes slept at 2250 m and trained at altitudes < 1200 m. Hbmass was measured in duplicate with the optimized carbon monoxide rebreathing method before (pre-) and immediately after (post-) each 18 d training camp.
Results:
Hbmass increased similarly in HH (916 to 957 g, 4.5 ± 2.2%, P < 0.001) and in NH (918 to 953 g, 3.8 ± 2.6%, P < 0.001). Hbmass changes did not differ between HH and NH (P = 0.42). There was substantial inter-individual variability among subjects to both interventions (i.e., individual responsiveness, or the individual variation in the response to an intervention free of technical noise): 0.9% in HH and 1.7% in NH. However, a correlation between intra-individual delta Hbmass changes (%) in HH and in NH (r = 0.52, P = 0.048) was observed.
Conclusion:
HH and NH evoked similar mean Hbmass increases following LHTL. Among the mean Hbmass changes, there was a notable variation in individual Hbmass response, which tended to be reproducible.
Alpinsport ist „in“, das zeigen aktuelle Statistiken: Unter den alpinen Urlaubsgästen befinden sich etwa 20 Millionen Skifahrer, 5–10 Millionen Wanderer, 3 Millionen Mountainbiker, 500.000 Kletterer und 100.000 Skitourengeher. Gerade aus sportmedizinischer und sportwissenschaftlicher Sicht ist es ein Anliegen, verstärkt auf die Bedeutung der Physiologie der mittleren Höhe hinzuweisen. Im Folgenden wird auf die Anpassung des menschlichen Organismus an mittlere Höhenlagen eingegangen, wobei besonders das Herz-Kreislauf-System, das blutbildende System und der Flüssigkeitshaushalt berücksichtigt werden. Ein zweiter Schwerpunkt des Artikels ist die Zusammenfassung aktueller Erkenntnisse zur vieldiskutierten Thematik des Höhentrainings.
Intermittierende Hypoxie (IH) ist definiert als wiederholte Sauerstoffmangelexpositionen, welche durch Phasen mit normalem Sauerstoffangebot unterbrochen sind. Im Bereich des Höhentrainings kann IH über eine Erhöhung der Sauerstofftransportkapazität des Blutes oder über eine Verbesserung der Bewegungsökonomie zur Optimierung der Ausdauerleistung in Tallage führen. Eine generelle Empfehlung für die Gestaltung des Höhentrainings kann basierend auf den wissenschaftlichen Ergebnissen nicht gegeben werden. Für die Anwendung von IH zur Präakklimatisation können Nächtigungen in Höhen über 2000 m oder möglichst häufige Tagesaufenthalte bis über 3000 m empfohlen werden. Ebenso dürften Nächtigungen in normobarer Hypoxie und wiederholte 3- bis 4-stündige Expositionen über 4000 m simulierter Höhe Präakklimatisationseffekte hervorrufen. Für IH-Protokolle mit Hypoxieexpositionen von ca. 1 Stunde ist die AMS-Prophylaxe fraglich.
The overall "hypoxic dose" associated with altitude training for athletes is typically reported in the literature as hours of exposure. Current recommendations for altitude training are based around the need to acquire a given number of hours within a specific altitude range (typically 1800-3000 m); with the expected erythropoietic change proportional to the hours accumulated. We propose that elevation should also be incorporated when calculating the total dose of altitude exposure and introduce a new metric termed "kilometer hours" to define overall hypoxic dose.
Objectives:
To determine the efficacy of live-high train-low on team-sport athlete physical capacity and the time-course for adaptation.
Design:
Pre-post parallel-groups.
Methods:
Fifteen Australian footballers were matched for Yo-Yo Intermittent recovery test level 2 (Yo-YoIR2) performance and assigned to LHTL (n=7) or control (Con; n=8). LHTL spent 19 nights (3×5 nights, 1×4 nights, each block separated by 2 nights at sea level) at 3000-m simulated altitude (FIO2: 0.142). Yo-Yo IR2 was performed pre and post 5, 15, and 19 nights. A 2- and 1-km time-trial (TT) was performed pre and post intervention. Haemoglobin mass (Hbmass) was measured in LHTL after 5, 10, 15, and 19 nights. A contemporary statistical approach using effect size, confidence limits, and magnitude-based inferences was used to measure changes between groups.
Results:
Compared to pre, Hbmass was possibly higher after 15 (3.8%, effect size (ES) 0.19, 90% confidence limits 0.05-0.33) and very likely higher after 19 nights (6.7%, 0.35, 0.10; 0.52). For Yo-Yo IR2, LHTL group change was not meaningfully different to Con after 5 nights, possibly greater after 15 (10.2%, 0.37, -0.29; 1.04), and likely greater after 19 nights (13.5%, 0.49, -0.16; 1.14). Both groups improved 2-km TT, with LHTL improvement possibly higher than CON (1.9%, 0.22, -0.18; 0.62). Only LHTL improved 1-km TT, with LHTL improvement likely greater than CON (4.6%, 0.56, -0.08; 1.04).
Conclusions:
Fifteen nights of LHTL was possibly effective, while 19 nights was effective at increasing Hbmass, Yo-Yo IR2 and repeated TT performance more than sea-level training.
A study of a sample provides only an estimate of the true (population) value of an outcome statistic. A report of the study therefore usually includes an inference about the true value. Traditionally, a researcher makes an inference by declaring the value of the statistic statistically significant or nonsignificant on the basis of a P value derived from a null-hypothesis test. This approach is confusing and can be misleading, depending on the magnitude of the statistic, error of measurement, and sample size. The authors use a more intuitive and practical approach based directly on uncertainty in the true value of the statistic. First they express the uncertainty as confidence limits, which define the likely range of the true value. They then deal with the real-world relevance of this uncertainty by taking into account values of the statistic that are substantial in some positive and negative sense, such as beneficial or harmful. If the likely range overlaps substantially positive and negative values, they infer that the outcome is unclear; otherwise, they infer that the true value has the magnitude of the observed value: substantially positive, trivial, or substantially negative. They refine this crude inference by stating qualitatively the likelihood that the true value will have the observed magnitude (eg, very likely beneficial). Quantitative or qualitative probabilities that the true value has the other 2 magnitudes or more finely graded magnitudes (such as trivial, small, moderate, and large) can also be estimated to guide a decision about the utility of the outcome.
The purpose of the study was to determine the relationship between running economy and distance running performance in highly trained and experienced distance runners of comparable ability. Oxygen uptake (Vo2) during steady-state and maximal aerobic power (Vo2max) were measured during treadmill running using the open-circuit method. Distance running performance was determined in a nationally prominent 10 km race; all subjects (12 males) placed among the top 19 finishers. The subjects averaged 32.1 min on the 10 km run, 71.7 ml.kg-1.min-1 for Vo2max, and 44.7, 50.3, and 55.9 ml.kg-1.min-1 for steady-state Vo2 at three running paces (241, 268, and 295 m.min-1). The relationship between Vo2max and distance running performance was r = -0.12 (p = 0.35). The relationship between steady-state Vo2 at 241, 268 and 295 m.min-1 and 10 km time were r = 0.83, 0.82, and 0.79 (p < 0.01), respectively. Within this elite cluster of finishers, 65.4% of the variation observed in race performance time on the 10 km run could be explained by variation in running economy. It was concluded that among highly trained and experienced runners of comparable ability and similar Vo2max, running economy accounts for a large and significant amount of the variation observed in performance on a 10 km race.
To investigate the benefits of 'living high and training low' on anaerobic performance at sea level, eight 400-m runners lived for 10 days in normobaric hypoxia in an altitude house (oxygen content = 15.8%) and trained outdoors in ambient normoxia at sea level. A maximal anaerobic running test and 400-m race were performed before and within 1 week of living in the altitude house to determine the maximum speed and the speeds at different submaximal blood lactate concentrations (3, 5, 7, 10 and 13 mmol x l(-1)) and 400-m race time. At the same time, ten 400-m runners lived and trained at sea level and were subjected to identical test procedures. Multivariate analysis of variance indicated that the altitude house group but not the sea-level group improved their 400-m race time during the experimental period (P < 0.05). The speeds at blood lactate concentrations of 5-13 mmol x l(-1) tended to increase in the altitude house group but the response was significant only at 5 and 7 mmol x l(-1) (P < 0.05). Furthermore, resting blood pH was increased in six of the eight altitude house athletes from 0.003 to 0.067 pH unit (P < 0.05). The results of this study demonstrate improved 400-m performance after 10 days of living in normobaric hypoxia and training at sea level. Furthermore, the present study provides evidence that changes in the acid-base balance and lactate metabolism might be responsible for the improvement in sprint performance.
This study investigated whether hypoxic exposure increased muscle buffer capacity (beta(m)) and mechanical efficiency during exercise in male athletes. A control (CON, n=7) and a live high:train low group (LHTL, n=6) trained at near sea level (600 m), with the LHTL group sleeping for 23 nights in simulated moderate altitude (3000 m). Whole body oxygen consumption (VO2) was measured under normoxia before, during and after 23 nights of sleeping in hypoxia, during cycle ergometry comprising 4 x 4-min submaximal stages, 2-min at 5.6 +/- 0.4 W kg(-1), and 2-min 'all-out' to determine total work and VO(2peak). A vastus lateralis muscle biopsy was taken at rest and after a standardized 2-min 5.6 +/- 0.4 W kg(-1) bout, before and after LHTL, and analysed for beta(m) and metabolites. After LHTL, beta(m) was increased (18%, P < 0.05). Although work was maintained, VO(2peak) fell after LHTL (7%, P < 0.05). Submaximal VO2 was reduced (4.4%, P < 0.05) and efficiency improved (0.8%, P < 0.05) after LHTL probably because of a shift in fuel utilization. This is the first study to show that hypoxic exposure, per se, increases muscle buffer capacity. Further, reduced VO2 during normoxic exercise after LHTL suggests that improved exercise efficiency is a fundamental adaptation to LHTL.
The purpose of our study was to evaluate hematologic acclimatization during 2 weeks of intensive normoxic training with regeneration at moderate altitude (living high-training low, LHTL) and its effects on sea-level performance in well trained athletes compared to another group of equally trained athletes under control conditions (living low - training low, CONTROL). Twenty-one triathletes were ascribed either to LHTL (n = 11; age: 23.0 +/- 4.3 yrs; VO 2 max: 62.5 +/- 9.7 [ml x min -1 x kg -1]) living at 1956 m of altitude or to CONTROL (n = 10; age: 18.7 +/- 5.6 yrs; VO 2 max: 60.5 +/- 6.7 ml x min -1 x kg -1) living at 800 m. Both groups performed an equal training schedule at 800 m. VO 2 max, endurance performance, erythropoietin in serum, hemoglobin mass (Hb tot, CO-rebreathing method) and hematological quantities were measured. A tendency to improved performance in LHTL after the camp was not significant (p < 0.07). Erythropoietin concentration increased temporarily in LHTL (Delta 14.3 +/- 8.7 mU x ml -1; p < 0.012). Hb tot remained unchanged in LHTL whereas was slightly decreased from 12.5 +/- 1.3 to 11.9 +/- 1.3g x kg -1 in CONTROL (p < 0.01). As the reticulocyte number tended to higher values in LHTL than in CONTROL, it seems that a moderate stimulation of erythropoiesis during regeneration at altitude served as a compensation for an exercise-induced destruction of red cells.
To investigate the effect of altitude exposure on running economy (RE), 22 elite distance runners [maximal O(2) consumption (Vo(2)) 72.8 +/- 4.4 ml x kg(-1) x min(-1); training volume 128 +/- 27 km/wk], who were homogenous for maximal Vo(2) and training, were assigned to one of three groups: live high (simulated altitude of 2,000-3,100 m)-train low (LHTL; natural altitude of 600 m), live moderate-train moderate (LMTM; natural altitude of 1,500-2,000 m), or live low-train low (LLTL; natural altitude of 600 m) for a period of 20 days. RE was assessed during three submaximal treadmill runs at 14, 16, and 18 km/h before and at the completion of each intervention. Vo(2), minute ventilation (Ve), respiratory exchange ratio, heart rate, and blood lactate concentration were determined during the final 60 s of each run, whereas hemoglobin mass (Hb(mass)) was measured on a separate occasion. All testing was performed under normoxic conditions at approximately 600 m. Vo(2) (l/min) averaged across the three submaximal running speeds was 3.3% lower (P = 0.005) after LHTL compared with either LMTM or LLTL. Ve, respiratory exchange ratio, heart rate, and Hb(mass) were not significantly different after the three interventions. There was no evidence of an increase in lactate concentration after the LHTL intervention, suggesting that the lower aerobic cost of running was not attributable to an increased anaerobic energy contribution. Furthermore, the improved RE could not be explained by a decrease in Ve or by preferential use of carbohydrate as a metabolic substrate, nor was it related to any change in Hb(mass). We conclude that 20 days of LHTL at simulated altitude improved the RE of elite distance runners.
The efficiency of "living high, training low" (LHTL) remains controversial, despite its wide utilization. This study aimed to verify whether maximal and/or submaximal aerobic performance were modified by LHTL and whether these effects persist for 15 days after returning to normoxia. Last, we tried to elucidate whether the mechanisms involved were only related to changes in oxygen-carrying capacity. Eleven elite middle-distance runners were tested before (Pre), at the end (Post1), and 15 days after the end (Post2) of an 18-day LHTL session. Hypoxic group (LHTL, n = 5) spent 14 h/day in hypoxia (6 nights at 2,500 m and 12 nights at 3,000 m), whereas the control group (CON, n = 6) slept in normoxia (1,200 m). Both LHTL and CON trained at 1,200 m. Maximal oxygen uptake and maximal aerobic power were improved at Post1 and Post2 for LHTL only (+7.1 and +3.4% for maximal oxygen uptake, +8.4 and +4.7% for maximal aerobic power, respectively). Similarly oxygen uptake and ventilation at ventilatory threshold increased in LHTL only (+18.1 and +12.2% at Post1, +15.9 and +15.4% at Post2, respectively). Heart rate during a 10-min run at 19.5 km/h decreased for LHTL at Post2 (-4.4%). Despite the stimulation of erythropoiesis in LHTL shown by the 27.4% increase in serum transferrin receptor and the 10.1% increase in total hemoglobin mass, red cell volume was not significantly increased at Post1 (+9.2%, not significant). Therefore, both maximal and submaximal aerobic performance in elite runners were increased by LHTL mainly linked to an improvement in oxygen transport in early return to normoxia and probably to other process at Post2.
The “living high–training low” model (LHTL), i.e., training in normoxia but sleeping/living in hypoxia, is designed to improve the athletes performance. However, LHTL efficacy still remains controversial and also little is known about the duration of its potential benefit. This study tested whether LHTL enhances aerobic performance in athletes, and if any positive effect may last for up to 2 weeks after LHTL intervention. Eighteen swimmers trained for 13 days at 1,200 m while sleeping/living at 1,200 m in ambient air (control, n=9) or in hypoxic rooms (LHTL, n=9, 5 days at simulated altitude of 2,500 m followed by 8 days at simulated altitude of 3,000 m, 16 h day−1). Measures were done before 1–2 days (POST-1) and 2 weeks after intervention (POST-15). Aerobic performance was assessed from two swimming trials, exploring
\( \ifmmode\expandafter\dot\else\expandafter\.\fi{V}{\text{O}}_{{2\max }} \) and endurance performance (2,000-m time trial), respectively. Reticulocyte, serum EPO and soluble transferrin receptor responses were not altered by LHTL, whereas reticulocytes decreased in controls. In POST-1 (vs. before): red blood cell volume increased in LHTL only (+8.5%, P=0.03),
\( \ifmmode\expandafter\dot\else\expandafter\.\fi{V}{\text{O}}_{{2\max }} \) tended to increase more in LHTL (+8.1%, P=0.09) than in controls (+2.5%, P=0.21) without any difference between groups (P=0.42) and 2,000-m performance was unchanged with LHTL. In POST-15, both performance and hematological parameters were similar to initial levels. Our results indicate that LHTL may stimulate red cell production, without any concurrent amelioration of aerobic performance. The absence of any prolonged benefit after LHTL suggests that this LHTL model cannot be recommended for long-term purposes.
It is unclear whether world class endurance athletes, in contrast with less well trained subjects, increase their haemoglobin mass on a regimen of living high and training low (LHTL).
To assess whether haemoglobin mass increases in world class athletes on LHTL and whether this increase is associated with peak performance at a subsequent important competition.
Two Swiss world class runners (one 5000 m and one marathon) lived for 26 days (18 hours a day) at an altitude of 2456 m and trained at 1800 m. This LHTL camp was the preparation for the World Athletic Championships taking place 27-29 days after the end of the camp. Haemoglobin mass and other haematological variables were measured before and after the LHTL camp. The performance parameter was the race times during that period.
Haemoglobin mass increased by 3.9% and 7.6%, and erythrocyte volume by 5.8% and 6.3%. The race times, as well as the ranking at the World Championships, indicated clearly improved performance after the LHTL camp.
The results suggest that LHTL with an adequate dose of hypoxia can increase haemoglobin mass even in world class athletes, which may translate into improved performance at important competitions at sea level.
The effect of live high-train low on hemoglobin mass (Hbmass) and red cell volume (RCV) in elite endurance athletes is still controversial. We expected that Hb(mass) and RCV would increase, when using a presumably adequate hypoxic dose. An altitude group (AG) of 10 Swiss national team orienteers (5 men and 5 women) lived at 2,500 m (18 h per day) and trained at 1,800 and 1,000 m above sea level for 24 days. Before and after altitude, Hbmass, RCV (carbon monoxide rebreathing method), blood, iron, and performance parameters were determined. Seven Swiss national team cross-country skiers (3 men and 4 women) served as "sea level" (500-1,600 m) control group (CG) for the changes in Hbmass and RCV. The AG increased Hbmass (805+/-209 vs. 848+/-225 g; P<0.01) and RCV (2,353+/-611 vs. 2,470+/-653 ml; P<0.01), whereas there was no change for the CG (Hbmass: 849+/-197 vs. 858+/-205 g; RCV: 2,373+/-536 vs. 2,387+/-551 ml). Serum erythropoietin (P<0.001), reticulocytes (P<0.001), transferrin (P<0.001), soluble transferrin receptor (P<0.05), and hematocrit (P<0.01) increased, whereas ferritin (P<0.05) decreased in the AG. These changes were associated with an increased maximal oxygen uptake (3,515+/-837 vs. 3,660+/-770 ml/min; P<0.05) and improved 5,000-m running times (1,098+/-104 vs. 1,080+/-98 s; P<0.01) from pre- to postaltitude. Living at 2,500 m and training at lower altitudes for 24 days increases Hbmass and RCV. These changes may contribute to enhance performance of elite endurance athletes.
The "living high-training low" model (Hi-Lo) may improve aerobic performance in athletes, and the main mechanism of this improvement is thought to be augmented erythropoiesis. A positive effect of Hi-Lo has been demonstrated previously by using altitudes of 2,000-3,000 m. Since the rate of erythropoiesis is altitude-dependent, we tested whether a higher altitude (3,500 m) during Hi-Lo increases erythropoiesis and maximal aerobic performance. Nordic skiers trained for 18 days at 1,200 m, while sleeping at 1,200 m in ambient air (control group, n = 5) or in hypoxic rooms (Hi-Lo, n = 6; 3 x 6 days at simulated altitudes of 2,500, 3,000 and finally 3,500 m, 11 h day(-1)). Measurements were done before, during (blood samples only) and 2 weeks after the intervention (POST). Maximal aerobic performance was examined from VO(2max) and time to exhaustion (T(exh)) at vVO(2max) (minimum speed associated with VO(2max)), respectively. Erythropoietin and soluble transferrin receptor responses were higher during Hi-Lo, whereas reticulocytes did not change. In POST (vs. before): hematological parameters were similar to basal levels, as well as red blood cell volume, being 2.68 +/- 0.83 l (vs. 2.64+/-0.54 l) in Hi-Lo and 2.62+/-0.57 l (vs. 2.87 +/- 0.59 l) in controls. At that time, neither VO(2max) nor T(exh) were improved by Hi-Lo, VO(2max) being non-significantly decreased by 2.0% (controls) and 3.7% (Hi-Lo). The present results suggest that increasing the altitude up to 3,500 m during Hi-Lo stimulates erythropoiesis but does not confer any advantage for maximal O2 transport.
This double-blind, randomized, placebo-controlled trial examined the effects of 4 wk of resting exposure to intermittent hypobaric hypoxia (IHE, 3 h/day, 5 days/wk at 4,000-5,500 m) or normoxia combined with training at sea level on performance and maximal oxygen transport in athletes. Twenty-three trained swimmers and runners completed duplicate baseline time trials (100/400-m swims, or 3-km run) and measures for maximal oxygen uptake (VO(2max)), ventilation (VE(max)), and heart rate (HR(max)) and the oxygen uptake at the ventilatory threshold (VO(2) at VT) during incremental treadmill or swimming flume tests. Subjects were matched for sex, sport, performance, and training status and divided randomly between hypobaric hypoxia (Hypo, n = 11) and normobaric normoxia (Norm, n = 12) groups. All tests were repeated within the first (Post1) and third weeks (Post2) after the intervention. Time-trial performance did not improve in either group. We could not detect a significant difference between groups for a change in VO(2max), VE(max), HR(max), or VO(2) at VT after the intervention (group x test interaction P = 0.31, 0.24, 0.26, and 0.12, respectively). When runners and swimmers were considered separately, Hypo swimmers appeared to increase VO(2max) (+6.2%, interaction P = 0.07) at Post2 following a precompetition taper and increased VO(2) at VT (+8.9 and +12.1%, interaction P = 0.007 and 0.006, at Post1 and Post2). We conclude that this "dose" of IHE was not sufficient to improve performance or oxygen transport in this heterogeneous group of athletes. Whether there are potential benefits of this regimen for specific sports or training/tapering strategies may require further study.
Acclimatization to moderate high altitude accompanied by training at low altitude (living high-training low) has been shown to improve sea level endurance performance in accomplished, but not elite, runners. Whether elite athletes, who may be closer to the maximal structural and functional adaptive capacity of the respiratory (i.e., oxygen transport from environment to mitochondria) system, may achieve similar performance gains is unclear. To answer this question, we studied 14 elite men and 8 elite women before and after 27 days of living at 2,500 m while performing high-intensity training at 1,250 m. The altitude sojourn began 1 wk after the USA Track and Field National Championships, when the athletes were close to their season's fitness peak. Sea level 3,000-m time trial performance was significantly improved by 1.1% (95% confidence limits 0.3–1.9%). One-third of the athletes achieved personal best times for the distance after the altitude training camp. The improvement in running performance was accompanied by a 3% improvement in maximal oxygen uptake (72.1 ± 1.5 to 74.4 ± 1.5 ml · kg ⁻¹ · min ⁻¹ ). Circulating erythropoietin levels were near double initial sea level values 20 h after ascent (8.5 ± 0.5 to 16.2 ± 1.0 IU/ml). Soluble transferrin receptor levels were significantly elevated on the 19th day at altitude, confirming a stimulation of erythropoiesis (2.1 ± 0.7 to 2.5 ± 0.6 μg/ml). Hb concentration measured at sea level increased 1 g/dl over the course of the camp (13.3 ± 0.2 to 14.3 ± 0.2 g/dl). We conclude that 4 wk of acclimatization to moderate altitude, accompanied by high-intensity training at low altitude, improves sea level endurance performance even in elite runners. Both the mechanism and magnitude of the effect appear similar to that observed in less accomplished runners, even for athletes who may have achieved near maximal oxygen transport capacity for humans.
Purpose:
The purpose of this study was to assess research aimed at measuring performance enhancements that affect success of individual elite athletes in competitive events.
Analysis:
Simulations show that the smallest worthwhile enhancement of performance for an athlete in an international event is 0.7-0.4 of the typical within-athlete random variation in performance between events. Using change in performance in events as the outcome measure in a crossover study, researchers could delimit such enhancements with a sample of 16-65 athletes, or with 65-260 in a fully controlled study. Sample size for a study using a valid laboratory or field test is proportional to the square of the within-athlete variation in performance in the test relative to the event; estimates of these variations are therefore crucial and should be determined by repeated-measures analysis of data from reliability studies for the test and event. Enhancements in test and event may differ when factors that affect performance differ between test and event; overall effects of these factors can be determined with a validity study that combines reliability data for test and event. A test should be used only if it is valid, more reliable than the event, allows estimation of performance enhancement in the event, and if the subjects replicate their usual training and dietary practices for the study; otherwise the event itself provides the only dependable estimate of performance enhancement. Publication of enhancement as a percent change with confidence limits along with an analysis for individual differences will make the study more applicable to athletes. Outcomes can be generalized only to athletes with abilities and practices represented in the study.
Conclusion:
estimates of enhancement of performance in laboratory or field tests in most previous studies may not apply to elite athletes in competitive events.
Total haemoglobin mass can be easily measured by applying the optimised CO-rebreathing method (oCOR-method). Prerequisite for its accurate determination is a homogenous CO distribution in the blood and the exact knowledge of the CO volume circulating in the vascular space. The aim of the study was to evaluate the mixing time of CO in the blood after inhaling a CO-bolus and to quantify the CO volume leaving the vascular bed due to diffusion to myoglobin and due to exhalation during processing the oCOR-method. The oCOR-method was also compared to a former commonly used CO-rebreathing procedure. In ten subjects, the time course of carboxy-haemoglobin (HbCO) formation was analysed simultaneously in capillary and venous blood for a period of 15 min after inhaling a CO bolus. The volume of CO diffusing from haemoglobin to myoglobin was calculated via the decrease of HbCO. As part of this decrease is due to CO exhalation, this volume was quantified by collecting the exhaled air in a Douglas bag system. Equal HbCO values in capillary and venous blood were reached at min 6 indicating complete mixing of CO. The loss of CO out of the vascular bed due to exhalation and due to diffusion to myoglobin was 0.32 +/- 0.12% min(-1) (0.25 +/- 0.09 ml min(-1)) and 0.32 +/- 0.18% min(-1) (0.24 +/- 0.13 ml min(-1)) of the administered CO volume, respectively. The loss of CO due to exhalation and diffusion to myoglobin is of minor impact. It should, however, be considered by using correction factors to obtain high accuracy when determining total haemoglobin mass.
The effect of repeated exposures to natural and simulated moderate altitude on physiology and competitive performance of elite athletes warrants further investigation. This study quantified changes in hemoglobin mass, performance tests, and competitive performance of elite swimmers undertaking a coach-prescribed program of natural and simulated altitude training. Nine swimmers (age 21.1 +/- 1.4 years, mean +/- SD) completed up to four 2-week blocks of combined living and training at moderate natural altitude (1,350 m) and simulated live high-train low (2,600-600 m) altitude exposure between 2 National Championships. Changes in hemoglobin mass (Hbmass), 4-mM lactate threshold velocity, and 2,000 m time trial were measured. Competition performance of these swimmers was compared with that of 9 similarly trained swimmers (21.1 +/- 4.1 years) who undertook no altitude training. Each 2-week altitude block on average produced the following improvements: Hbmass, 0.9% (90% confidence limits, +/-0.8%); 4-mM lactate threshold velocity, 0.9% (+/-0.8%); and 2,000 m time trial performance, 1.2% (+/-1.6%). The increases in Hbmass had a moderate correlation with time trial performance (r = 0.47; +/-0.41) but an unclear correlation with lactate threshold velocity (r = -0.23; +/-0.48). The altitude group did not swim faster at National Championships compared with swimmers who did not receive any altitude exposure, the difference between the groups was not substantial (-0.5%; +/-1.0%). A coach-prescribed program of repeated altitude training and exposure elicited modest changes in physiology but did not substantially improve competition performance of elite swimmers. Sports should investigate the efficacy of their altitude training program to justify the investment.
The aim of this study was to determine the time course of changes in haemoglobin mass (Hb(mass)) in well-trained cyclists in response to live high:train low (LHTL). Twelve well-trained male cyclists participated in a 3-week LHTL protocol comprising 3,000 m simulated altitude for ~14 h/day. Prior to LHTL duplicate baseline measurements were made of Hb(mass), maximal oxygen consumption (VO(2max)) and serum erythropoietin (sEPO). Hb(mass) was measured weekly during LHTL and twice in the week thereafter. There was a 3.3% increase in Hb(mass) and no change in VO(2max) after LHTL. The mean Hb(mass) increased at a rate of ~1% per week and this was maintained in the week after cessation of LHTL. The sEPO concentration peaked after two nights of LHTL but there was only a trivial correlation (r = 0.04, P = 0.89) between the increase in sEPO and the increase in Hb(mass). Athletes seeking to gain erythropoietic benefits from moderate altitude need to spend >12 h/day in hypoxia.
Statistical guidelines and expert statements are now available to assist in the analysis and reporting of studies in some biomedical disciplines. We present here a more progressive resource for sample-based studies, meta-analyses, and case studies in sports medicine and exercise science. We offer forthright advice on the following controversial or novel issues: using precision of estimation for inferences about population effects in preference to null-hypothesis testing, which is inadequate for assessing clinical or practical importance; justifying sample size via acceptable precision or confidence for clinical decisions rather than via adequate power for statistical significance; showing SD rather than SEM, to better communicate the magnitude of differences in means and nonuniformity of error; avoiding purely nonparametric analyses, which cannot provide inferences about magnitude and are unnecessary; using regression statistics in validity studies, in preference to the impractical and biased limits of agreement; making greater use of qualitative methods to enrich sample-based quantitative projects; and seeking ethics approval for public access to the depersonalized raw data of a study, to address the need for more scrutiny of research and better meta-analyses. Advice on less contentious issues includes the following: using covariates in linear models to adjust for confounders, to account for individual differences, and to identify potential mechanisms of an effect; using log transformation to deal with nonuniformity of effects and error; identifying and deleting outliers; presenting descriptive, effect, and inferential statistics in appropriate formats; and contending with bias arising from problems with sampling, assignment, blinding, measurement error, and researchers' prejudices. This article should advance the field by stimulating debate, promoting innovative approaches, and serving as a useful checklist for authors, reviewers, and editors.
The energy cost of the forms of locomotion discussed throughout this article is summarized in Table 9. This table, as well as the preceding sections of this article, are designed to provide a rather comprehensive and simple set of information for potential readers: medical doctors, who should be able to prescribe to their patients (obese, hypertensive, cardiac, etc.) the correct amount and type of exercise, thus making use of exercise as of any other drug, of which it is imperative to know posology and contraindications; athletes, trainers, and sportsmen in general, who should gear correctly their diet to the type and amount of physical exercise; physical educators, who should be aware of the specific characteristics of the exercise modes they propose to their pupils, as a function of their sex, age, and athletic capacity. However, besides these practical applications, the notions discussed throughout this article bear also a more general interest. Indeed, they allow a better understanding of the motion of man, that is, of the only machine, which besides moving about, also tries to understand how he does it.
The maximal ability to deliver oxygen to the tissues of the body establishes the upper limit of endurance performance; however, the ability of the skeletal muscles to utilize a high oxygen load for a sustained period of time is also of great importance. The fatigue that limits endurance is due to a local limitation of oxygen or substrate, which leads to excessive anaerobic metabolism or decreased energy production. The peripheral adaptation from specific and intense training may further improve endurance performance.
The purpose of the study was to determine the relationship between the percentage of maximal heart rate (HR max) at submaximal running paces and distance running performance in highly trained and experienced distance runners of comparable ability. Heart rates during steady-state submaximal work and maximal work on a treadmill were monitored with the Narco-Bio Systems physioscope and bio-tachometer with digital read-out and recorded with a Park-Davis EKG machine. Distance running performance was determined in a nationally prominent 10 km race. The 12 male subjects placed among the top 19 finishers with over 4000 entries. The subjects averaged 32.1 min on the 10 km run, 71.7 ml/kg/min for V̇O2 max, and 79.3, 85.0, 90.4 percentage of HR max at the three running paces (241, 268, 295 m/min). The relationship between the percentage of HR max and distance running performance at 241, 268 and 295 m/min and 10 km race time were r = 0.90, 0.89, and 0.73 (p < 0.01), respectively. It was concluded that among highly trained and experienced distance runners of comparable ability, the percentage of HR max accounts for a large and significant amount of the variation observed in performance on a 10 km race.
The principal objective of this study was to test the hypothesis that acclimatization to moderate altitude (2,500 m) plus training at low altitude (1,250 m), "living high-training low," improves sea-level performance in well-trained runners more than an equivalent sea-level or altitude control. Thirty-nine competitive runners (27 men, 12 women) completed 1) a 2-wk lead-in phase, followed by 2) 4 wk of supervised training at sea level; and 3) 4 wk of field training camp randomized to three groups: "high-low" (n = 13), living at moderate altitude (2,500 m) and training at low altitude (1,250 m); "high-high" (n = 13), living and training at moderate altitude (2,500 m); or "low-low" (n = 13), living and training in a mountain environment at sea level (150 m). A 5,000-m time trial was the primary measure of performance; laboratory outcomes included maximal O2 uptake (VO2 max), anaerobic capacity (accumulated O2 deficit), maximal steady state (MSS; ventilatory threshold), running economy, velocity at VO2 max, and blood compartment volumes. Both altitude groups significantly increased VO2 max (5%) in direct proportion to an increase in red cell mass volume (9%; r = 0.37, P < 0.05), neither of which changed in the control. Five-kilometer time was improved by the field training camp only in the high-low group (13.4 +/- 10 s), in direct proportion to the increase in VO2 max (r = 0.65, P < 0.01). Velocity at VO2 max and MSS also improved only in the high-low group. Four weeks of living high-training low improves sea-level running performance in trained runners due to altitude acclimatization (increase in red cell mass volume and VO2 max) and maintenance of sea-level training velocities, most likely accounting for the increase in velocity at VO2 max and MSS.
Moderate-altitude living (2,500 m), combined with low-altitude training (1,250 m) (i.e., live high-train low), results in a significantly greater improvement in maximal O2 uptake (V(02)max) and performance over equivalent sea-level training. Although the mean improvement in group response with this "high-low" training model is clear, the individual response displays a wide variability. To determine the factors that contribute to this variability, 39 collegiate runners (27 men, 12 women) were retrospectively divided into responders (n = 17) and nonresponders (n = 15) to altitude training on the basis of the change in sea-level 5,000-m run time determined before and after 28 days of living at moderate altitude and training at either low or moderate altitude. In addition, 22 elite runners were examined prospectively to confirm the significance of these factors in a separate population. In the retrospective analysis, responders displayed a significantly larger increase in erythropoietin (Epo) concentration after 30 h at altitude compared with nonresponders. After 14 days at altitude, Epo was still elevated in responders but was not significantly different from sea-level values in nonresponders. The Epo response led to a significant increase in total red cell volume and V(O2) max in responders; in contrast, nonresponders did not show a difference in total red cell volume or V(O2)max after altitude training. Nonresponders demonstrated a significant slowing of interval-training velocity at altitude and thus achieved a smaller O2 consumption during those intervals, compared with responders. The acute increases in Epo and V(O2)max were significantly higher in the prospective cohort of responders, compared with nonresponders, to altitude training. In conclusion, after a 28-day altitude training camp, a significant improvement in 5,000-m run performance is, in part, dependent on 1) living at a high enough altitude to achieve a large acute increase in Epo, sufficient to increase the total red cell volume and V(O2)max, and 2) training at a low enough altitude to maintain interval training velocity and O2 flux near sea-level values.
The purpose of this study was to assess research aimed at measuring performance enhancements that affect success of individual elite athletes in competitive events.
Simulations show that the smallest worthwhile enhancement of performance for an athlete in an international event is 0.7-0.4 of the typical within-athlete random variation in performance between events. Using change in performance in events as the outcome measure in a crossover study, researchers could delimit such enhancements with a sample of 16-65 athletes, or with 65-260 in a fully controlled study. Sample size for a study using a valid laboratory or field test is proportional to the square of the within-athlete variation in performance in the test relative to the event; estimates of these variations are therefore crucial and should be determined by repeated-measures analysis of data from reliability studies for the test and event. Enhancements in test and event may differ when factors that affect performance differ between test and event; overall effects of these factors can be determined with a validity study that combines reliability data for test and event. A test should be used only if it is valid, more reliable than the event, allows estimation of performance enhancement in the event, and if the subjects replicate their usual training and dietary practices for the study; otherwise the event itself provides the only dependable estimate of performance enhancement. Publication of enhancement as a percent change with confidence limits along with an analysis for individual differences will make the study more applicable to athletes. Outcomes can be generalized only to athletes with abilities and practices represented in the study.
estimates of enhancement of performance in laboratory or field tests in most previous studies may not apply to elite athletes in competitive events.
The purpose of this study was to document the effect of 23 days of "live high, train low" on the haemoglobin mass of endurance athletes. Thirteen male subjects from either cycling, triathlon or cross-country skiing backgrounds participated in the study. Six subjects (HIGH) spent 8-10 h per night in a "nitrogen house" at a simulated altitude of 3000 m in normobaric hypoxia, whilst control subjects slept at near sea level (CONTROL, n = 7). Athletes logged their daily training sessions, which were conducted at 600 m. Total haemoglobin mass (as measured using the CO-rebreathing technique) did not change when measured before (D1 or D2) and after (D28) 23 nights of hypoxic exposure [HIGH 990 (127) vs 972 (97) g and CONTROL 1042 (133) vs 1033 (138) g, before and after simulated altitude exposure, respectively]. N