Factors affecting running economy in trained distance runners

Department of Physiology, Australian Institute of Sport, Belconnen, ACT.
Sports Medicine (Impact Factor: 5.32). 02/2004; 34(7):465-85. DOI: 10.2165/00007256-200434070-00005
Source: PubMed

ABSTRACT Running economy (RE) is typically defined as the energy demand for a given velocity of submaximal running, and is determined by measuring the steady-state consumption of oxygen (VO2) and the respiratory exchange ratio. Taking body mass (BM) into consideration, runners with good RE use less energy and therefore less oxygen than runners with poor RE at the same velocity. There is a strong association between RE and distance running performance, with RE being a better predictor of performance than maximal oxygen uptake (VO2max) in elite runners who have a similar VO2max). RE is traditionally measured by running on a treadmill in standard laboratory conditions, and, although this is not the same as overground running, it gives a good indication of how economical a runner is and how RE changes over time. In order to determine whether changes in RE are real or not, careful standardisation of footwear, time of test and nutritional status are required to limit typical error of measurement. Under controlled conditions, RE is a stable test capable of detecting relatively small changes elicited by training or other interventions. When tracking RE between or within groups it is important to account for BM. As VO2 during submaximal exercise does not, in general, increase linearly with BM, reporting RE with respect to the 0.75 power of BM has been recommended. A number of physiological and biomechanical factors appear to influence RE in highly trained or elite runners. These include metabolic adaptations within the muscle such as increased mitochondria and oxidative enzymes, the ability of the muscles to store and release elastic energy by increasing the stiffness of the muscles, and more efficient mechanics leading to less energy wasted on braking forces and excessive vertical oscillation. Interventions to improve RE are constantly sought after by athletes, coaches and sport scientists. Two interventions that have received recent widespread attention are strength training and altitude training. Strength training allows the muscles to utilise more elastic energy and reduce the amount of energy wasted in braking forces. Altitude exposure enhances discrete metabolic aspects of skeletal muscle, which facilitate more efficient use of oxygen. The importance of RE to successful distance running is well established, and future research should focus on identifying methods to improve RE. Interventions that are easily incorporated into an athlete's training are desirable.

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Available from: David B Pyne, Aug 08, 2015
    • "However, in analysing the trade-off hypothesis, Ruiz et al. (2013) did not observe this mechanism for the ACTN3 R577X polymorphism in swimming athletes. As previously shown, CoL is a special parameter which could be influenced by neuromuscular characteristics, such as strength and power, and physiological characteristics, such as aerobic metabolism (Saunders et al., 2004). Therefore, it would be biologically logical that the RX genotype may maximise the CoL to influence both muscle function and aerobic metabolism. "
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    ABSTRACT: Covering long distances was an important trait to human evolution and continues to be highlighted for health and athletic status. This ability is benefitted by a low cost of locomotion (CoL), meaning that the individuals who are able to expend less energy would be able to cover longer distances. The CoL has been shown to be influenced by distinct and even 'opposite' factors, such as physiological and muscular characteristics, which are genetically inherited. In this way, DNA alterations could be important determinants of the characteristics associated with the CoL. A polymorphism in the ACTN3 gene (R577X) has been related to physical performance, associating the X allele with endurance and the R allele with strength/power abilities. To investigate the influence of ACTN3 genotypes on the CoL. One hundred and fifty healthy male individuals performed two constant speed tests (at 10 and 12 km/h) to determine the CoL. Interestingly, the results showed that heterozygous individuals (RX genotype) presented significantly lower CoL compared to RR and XX individuals. It is argued that RX genotype might generate an intermediate strength-to-endurance phenotype, leading to a better phenotypic profile for energy economy during running and, consequently, for long-term locomotion.
    Annals of Human Biology 07/2015; DOI:10.3109/03014460.2015.1050065 · 1.15 Impact Factor
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    • "Currently there is great interest in assessing the force production of middle and long-distance runners, because the benefits of resistance training for such athletes have been demonstrated (Aagaard and Andersen, 2010; Beattie et al., 2014; Ronnestad and Mujika, 2013; Saunders et al., 2004; Taipale et al., 2013). For example, it has been demonstrated that well-trained long-distance runners increased their running economy, as well as the time until exhaustion at the maximal aerobic velocity, after 8 weeks of a maximal strength training program using 4 sets of 4 RM conducted three times a week (Støren et al., 2008). "
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    ABSTRACT: The aim of this study was to analyze the time-course of force production of elite middle and long-distance runners throughout an entire season and at the end of the off-season, as well as its relationships with training load and hormonal responses. Training load was recorded daily throughout an entire season by measuring and evaluating the session distance (km), training zone and session-RPE in a group of 15 elite middle and long-distance runners (12 men, 3 women; age=26.3±5.1yrs, BMI=19.7±1.1). Also, basal salivary-free cortisol levels were measured weekly, and 50-metre sprints, mean propulsive velocity (MPV), mean propulsive power (MPP), repetition maximum (RM) and peak rate of force development (RFD) of half-squats were measured 4 times during the season, and once more after the off-season break. There were no significant variations in force production during the season or after the off-season break, except for the RFD (-30.2%, p=0.005) values, which changed significantly from the beginning to the end of the season. Significant correlations were found between session-RPE and MPV (r=-0.650, p=0.004), MPP (r=-0.602, p=0.009), RM (r=-0.650, p=0.004), and the 50-metre sprint (r=0.560, p=0.015). Meanwhile, salivary-free cortisol correlated significantly with the 50-metre sprint (r=0.737, p<0.001) and the RM (r=-0.514, p=0.025). Finally, the training zone correlated with the 50-metre sprint (r=-0.463, p=0.041). Session-RPE, training zone and salivary-free cortisol levels are related to force production in elite middle and long-distance runners. Monitoring these variables could be a useful tool in controlling the training programmes of elite athletes.
    Journal of sports science & medicine 03/2015; 14:9-15. · 0.90 Impact Factor
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    • "This would bring about greater medio-lateral forces and hence a higher FPI. As previously described (Saunders et al., 2004) and also shown in the present study, low W ext and low f were directly related to low CoT. A significant positive correlation between CoT and W ext was also found by Bourdin and colleagues (Bourdin et al., 1995), who showed that W ext could explain a large part of the variation of CoT among subjects at a given velocity. "
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    Journal of Experimental Biology 11/2013; DOI:10.1242/jeb.091645 · 3.00 Impact Factor
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