RUNNING ECONOMYTHE FORGOTTEN FACTOR IN ELITE PERFORMANCE

Carl Foster and Alejandro Lucia

Outline• Background Information• Previous Research• Author’s Aims• The Basic Ingredients• Inclusion/Exclusion Criteria • Methods• Limitations of the Study• Take Home Messages• Applications • References

Terminology

• VO2MAX: The maximum amount of oxygen used per minute during prolonged high intensity exercise

• Efficient: achieving maximum productivity with minimum wasted effort or expense

• Economical: Synonym for efficient

• Steady State: A state obtained in moderate muscular exercise when the removal of lactic acid by oxidation keeps pace with its production.

Background• Running performance depends on a complex interplay of

factors• 1. A high cardiac output and a high rate of oxygen delivery to

working muscles • 2.The ability to sustain a high percentage of VO2MAX for long

periods of time• 3. The ability to move efficiently

• VO2MAX and fractional utilization of VO2MAX are widely studied determinants of running performance

• Unless VO2MAX is >70 mL/min/kg it is almost impossible to achieve world class running performances

Background• Established World Class Runners

• Expected average of 75-80 mL/min/kg

• Percentage VO2MAX that can be sustained for slightly >2 hours is approximately 80-90% for the ≈ 28 minutes (Marathon) and 90-95% (10 km)

Primary Questions

• 1. What is the range in running economy across the range of serious runners?

• 2. Are the differences in running economy based on anatomical differences?

• 3. Can running economy be improved?

Differences in Running Economy • Measured by running at progressively

increasing stages of 4-10 min duration.

• Running intensity is kept below the ventilatory threshold.

• Reference treadmill runs in the lab were done either on a flat treadmill, or a treadmill with a 1% gradient

• In an ideal world, such runs would be performed outdoors to fully account for wind resistance, the characteristics of the running surface & the minor undulations present on even level outdoor terrain.

Expression of Running Economy

Can be made in several ways:

• To interpolate (or extrapolate) the VO2 to a common running velocity (commonly 268 m.min-1 or 4.47 m.s-1)

• Differences in VO2MAX can be accentuated if the aerobic requirement of running is expressed as VO2/kg-0.75

• An alternative method of expressing running economy is in terms of the VO2 required to run 1km.

Expression of Running Economy

Anatomical Basis of Differences in Running Economy• Distance runners are generally small

people

• African runners who dominate distance running are often even smaller by such standards

• Observed to have very thin lower legs, which is a possible contributor to their excellent running economy

• Suggested that running economy is related to body dimensions generally and is not a uniquely ‘African’ element

• Extraordinary running economy may be a characteristic of small people generally and specifically small people with thin lower legs

Can Running Economy be Improved?

• Very few studies of strategies that might improve running economy have been done

• Interventions involving strength and/or plyometric training, altitude exposure and training in the heat have been reviewed with regards to improve running economy

• Altitude exposure has shown mixed results. Suggested simple exposure will improve running economy.

Can Running Economy be Improved?

• Reported by Billat et al that running economy improved secondary to adding relatively HI training in addition to baseline running

• However, further studies have shown that running economy improved subsequent to the addition of HI interval training to baseline mileage

Final Stretch• Running economy is clearly important

to running performance

• Considerable range of running economy, even amongst well trained runners

• Tendency for East African Runners to be more economical

• Evidence suggests that running economy improves with the addition of HI interval training to baseline mileage

• Suggested that future improvement in running performance will depend on improved economy

References• 1. Joyner MJ. Modeling optimal marathon

perfonnance on the basis of physiological factors. J Appl Physiol 1991; 71: 683-7

• 2. Pollock ML. Submaximal and maximal working capacity of elite distance runners: cardiorespiratory aspects. Ann N Y AcadSci 1976; 301: 310-22

• 3. Costill DL, Thomason H, Roberts E. Fractional utilization of the aerobic capacity during distance running. Med Sci Sports

• 1973; 5: 248-524. Conley DL, Krahenbuhl GS, Burkett LN. Training for aerobic

• capacity and running economy. Phys Sportsmed 1981; 9: 107-15

• • 5. Lucia A, Esteve-Lanao J, Olivan J, et al.

Physiological charac- teristics of the best Eritrean runners: exceptional running econ- omy. Appl Physiol Nutr Metab 2006; 31: 530-40

• 6. Saunders PU, Pyne DB, Telford RD, et al. Factors affecting running economy in trained distance

runners. Sports Med 2004; 34: 465-85

• 7. Saltin B, Larsen H, Terrados N, et al. Aerobic exercise capacity at sea level and at altitude in Kenyan boys, junior and senior runners compared to Scandinavian runners. Scand J Med Sci Sports 1995; 5: 209-21

• 8. Lucia A, Hoyos J, Perez M, et al. Inverse relationship between V02max and economy/efficiency in world-class cyclists. Med Sci Sports Exerc 2002; 34: 2079-84

• 9. Royer TD, Martin PE. Manipulations of leg mass and moment of inertia: effects on energy cost of walking. Med Sci Sports Exerc 2005; 37: 649-56

• 10. Billat VL, Flechet B, Petit B, et al. Interval training at V02max: effects on aerobic performance and overtraining markers. Med Sci Sports Exerc 1999; 31: 156-63