Performance Enhancement: What Are the Physiological Limits?

Lundby, Carsten; Robach, Paul

doi:10.1152/physiol.00052.2014

Cited by 76 publications

(66 citation statements)

References 106 publications

(95 reference statements)

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“…The present finding provides some support for Westgarth-Taylor et al [37] who reported reduced [La -] at the same absolute work rate (80% peak power output) after HIIT and Weston et al [38] who showed an increased buffering capacity was Endurance performance in well-trained athletes is influenced by physiological factors including V O2max, lactate threshold/critical power, gross mechanical efficiency and genetic predispositions [360] . Since V O2max remains fairly stable across an athletic career, and therefore has minimal potential for further improvement once high-load endurance training has been undertaken for several years [360] , it is unlikely that changes in V O2max resulted over the course of ~3-4 weeks in the present study.…”

Section: Km Time Trialsupporting

confidence: 82%

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Sex differences and training adaptations in relation to the lactate threshold and endurance exercise performance

Fisher¹

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The second lactate threshold (LT2) has long been associated with endurance performance in trained endurance athletes. In Australia, the state institutes and academies of sport utilise the modified maximum deviation (D-max) method to determine LT2 in endurance athletes for the purpose of establishing training intensities and indicating whether athletes are appropriately adapting to training loads. For LT2 methods to be considered valid, it had been suggested that strong associations with simulated endurance performance and the maximal lactate steady-state (MLSS) are required. Although research has established a strong relationship between the modified D-max and endurance performance, there are gaps in the literature which this thesis aims to investigate. iii appropriate measurement of ovarian hormones. Therefore, the second study extended study one, to explore the same experimental aims, in endurance-trained women (n = 12) whilst controlling for ovarian hormone concentrations through the use of hormonal contraceptives. When comparing to the men's results from study one, power output and V O2 at LT2 were also found to be significantly correlated with 40 km cycling performance in endurance-trained women. Additionally, combining maximal (peak power output and V O2max) and fractional utilisation (V O2 and power output at LT2) variables produced the strongest prediction of performance in women (r 2 = 0.87) and men (r 2 = 0.95). In women, VT2 was significantly higher than LT2 for all variables measured, despite no differences observed for the men. More women (73%) than men (50%) completed 30 min of cycling and elicited a steady-state [La -] at their LT2 power output, despite LT2 being significantly higher than the self-selected power output during a 40 km cycling time trial in women.The final study examined the sensitivity of the modified D-max LT2 to adapt to a brief highintensity interval training (HIIT) intervention in already-endurance trained men (n = 9) and women (n = 8). Although not significant, women (but not men) showed a trend towards LT2 power output improvement (2.2%; p = 0.08) post-HIIT. Mean 40 km time trial performance significantly improved in both men (-1.7%) and women (-2.6%), with no difference in the magnitude of change between sexes. Furthermore, although LT2 power output explained 77% of the improvement in 40 km cycling performance in women, none of the measured variables explained the performance improvement in men, suggesting that mechanisms other than those responsible for the LT2 were involved. The LT2-performance relationship was intensity-dependent in both men and women, shown by significant correlations at post-HIIT but not baseline. Some of the sex-related differences may, at least in part, be explained by the influence of oestradiol, perhaps by the exacerbation of the sex-based differences in substrate metabolism and subsequent effects on [La -] and fatigue, and/or greater cardiovascular stress in men than women.Collectively, these studies improve understanding of the modifie...

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Section: Km Time Trialsupporting

confidence: 82%

“…Since V O2max remains fairly stable across an athletic career, and therefore has minimal potential for further improvement once high-load endurance training has been undertaken for several years [360] , it is unlikely that changes in V O2max resulted over the course of ~3-4 weeks in the present study.…”

Section: Km Time Trialmentioning

confidence: 88%

Sex differences and training adaptations in relation to the lactate threshold and endurance exercise performance

Fisher¹

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“…The positive association between physical activity and blood volume (BV) was established in the late 1940s by Swedish scientists demonstrating that exercise‐trained men and women had higher values than inactive peers (Kjellberg et al., ). This finding has been confirmed on numerous occasions with cross‐sectional study designs (Dill et al., ; Brotherhood et al., ; Heinicke et al., ; Lundby & Robach, ), which nevertheless are limited to ascertain whether the augmented BV determined in trained individuals is primarily attributed to exercise training (ExT) per se or associated with other differences between individuals (e.g, genetics). Yet, on the basis of longitudinal studies, ExT is generally accepted to prompt BV expansion, at least in healthy young individuals (Convertino, , ; Sawka et al., ).…”

mentioning

confidence: 79%

“…Large increases in RBCV with ExT are mainly advocated on the basis of cross‐sectional comparisons (Heinicke et al., ), notwithstanding the fact that ExT‐related mechanisms stimulating erythropoiesis are uncertain (Montero et al., ,b). In turn, longitudinal ExT studies (not including any type of hypoxic training) have reported conflicting RBCV responsiveness, ranging from unaltered (Shoemaker et al., ; Stachenfeld et al., ; Takeno et al., ; Okazaki et al., , ; Gass et al., ; Helgerud et al., ) to 10% increments (Bonne et al., ), which nonetheless remains well below the absolute values observed in some athletes (Lundby & Robach, ). The small sample size, distinct training characteristics, study population, and methodology of previous studies may have compounded the determined effect of ExT on RBCV (Bass et al., ; Fortney & Senay, ; Convertino et al., ; Ray et al., ; Green et al., ; Stevens et al., ; Carroll et al., ; Shoemaker et al., ; McCarthy et al., ; Pickering et al., ; Stachenfeld et al., ; Mtinangi & Hainsworth, ; Takeno et al., ; Okazaki et al., , ; Gass et al., ; Helgerud et al., ).…”

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confidence: 99%

Red cell volume response to exercise training: Association with aging

Montero

Lundby

2016

Scandinavian Med Sci Sports

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Red blood cell volume (RBCV) is a main determinant of cardiorespiratory fitness in healthy individuals. However, it remains controversial to what extent exercise training (ExT) enhances RBCV. Therefore, we sought to systematically review and determine the effect of ExT on RBCV in healthy individuals across all ages. We conducted a systematic search of MEDLINE, Scopus, and Web of Science, since their inceptions until February 2016 for articles assessing the effect of ExT interventions (not including hypoxic training) on blood volumes in healthy individuals. A meta-analysis was performed to determine the mean difference (MD) in RBCV between post- and pre-ExT measurements. Thirty studies were included after systematic review, comprising a total of 299 healthy individuals (mean age = 19-71 years, 271 males). Exercise training programs primarily consisted in lower limb endurance training interventions (mean duration = 15.2 weeks). After data pooling, RBCV was not increased following ExT (MD = 49 mL, 95% CI = -11, 108; P = 0.11). In subgroup analyses, RBCV was increased after ExT in young and middle-aged individuals (mean age <60 year) (n = 106, MD = 81 mL, 95% CI = 0, 162; P < 0.05) but not in older study participants (mean age ≥60 year) (n = 110, MD = 13 mL, 95% CI = -76, 102; P = 0.77). Heterogeneity was not detected among studies in young and middle-aged (I = 0%) and older individuals (I = 0%). In conclusion, RBCV is moderately, yet consistently, enhanced by ExT in young and middle-aged but not in older healthy individuals. Therefore, RBCV adaptations to ExT appear to be age dependent.

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“…Consequently, concerning training effects (Platonov, 1999; Noakes, 2000; Abbiss and Laursen, 2005), concepts integrating the prescription of both intensity and duration within one model are needed with respect to the main aims in endurance training which are to increase maximal oxygen uptake, the maximal sustainable speed, or power (threshold speed), and to increase economy and time to exhaustion (Lundby and Robach, 2015). …”

Section: Introductionmentioning

confidence: 99%

Intensity- and Duration-Based Options to Regulate Endurance Training

Hofmann

Tschakert

2017

Front. Physiol.

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The regulation of endurance training is usually based on the prescription of exercise intensity. Exercise duration, another important variable of training load, is rarely prescribed by individual measures and mostly set from experience. As the specific exercise duration for any intensity plays a substantial role regarding the different kind of cellular stressors, degree, and kind of fatigue as well as training effects, concepts integrating the prescription of both intensity and duration within one model are needed. An according recent approach was the critical power concept which seems to have a physiological basis; however, the mathematical approach of this concept does not allow applying the three zones/two threshold model of metabolism and its different physiological consequences. Here we show the combination of exercise intensity and duration prescription on an individual basis applying the power/speed to distance/time relationship. The concept is based on both the differentiation of intensities by two lactate or gas exchange variables derived turn points, and on the relationship between power (or velocity) and duration (or distance). The turn points define three zones of intensities with distinct acute metabolic, hormonal, and cardio-respiratory responses for endurance exercise. A maximal duration exists for any single power or velocity such as described in the power-duration relationship. Using percentages of the maximal duration allows regulating fatigue, recovery time, and adaptation for any single endurance training session. Four domains of duration with respect to induced fatigue can be derived from maximal duration obtained by the power-duration curve. For any micro-cycle, target intensities and durations may be chosen on an individual basis. The model described here is the first conceptual framework of integrating physiologically defined intensities and fatigue related durations to optimize high-performance exercise training.

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Performance Enhancement: What Are the Physiological Limits?

Cited by 76 publications

References 106 publications

Sex differences and training adaptations in relation to the lactate threshold and endurance exercise performance

Sex differences and training adaptations in relation to the lactate threshold and endurance exercise performance

Red cell volume response to exercise training: Association with aging

Intensity- and Duration-Based Options to Regulate Endurance Training

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