Shorter Ground Contact Time and Better Running Economy: Evidence From Female Kenyan Runners.

Mooses, M, Haile, DW, Ojiambo, R, Sang, M, Mooses, K, Lane, AR, and Hackney, AC. Shorter ground contact time and better running economy: evidence from female Kenyan runners. J Strength Cond Res XX(X): 000-000, 2018-Previously, it has been concluded that the improvement in running economy (RE) might be considered as a key to the continued improvement in performance when no further increase in V[Combining Dot Above]O2max is observed. To date, RE has been extensively studied among male East African distance runners. By contrast, there is a paucity of data on the RE of female East African runners. A total of 10 female Kenyan runners performed 3 × 1,600-m steady-state run trials on a flat outdoor clay track (400-m lap) at the intensities that corresponded to their everyday training intensities for easy, moderate, and fast running. Running economy together with gait characteristics was determined. Participants showed moderate to very good RE at the first (202 ± 26 ml·kg·km) and second (188 ± 12 ml·kg·km) run trials, respectively. Correlation analysis revealed significant relationship between ground contact time (GCT) and RE at the second run (r = 0.782; p = 0.022), which represented the intensity of anaerobic threshold. This study is the first to report the RE and gait characteristics of East African female athletes measured under everyday training settings. We provided the evidence that GCT is associated with the superior RE of the female Kenyan runners.

[1]  F. Pozzi,et al.  Validity and Reliability of a Commercial Fitness Watch for Measuring Running Dynamics. , 2016, The Journal of orthopaedic and sports physical therapy.

[2]  Isabel S. Moore,et al.  Is There an Economical Running Technique? A Review of Modifiable Biomechanical Factors Affecting Running Economy , 2016, Sports Medicine.

[3]  Alena M. Grabowski,et al.  Effects of independently altering body weight and body mass on the metabolic cost of running , 2007, Journal of Experimental Biology.

[4]  Martin Mooses,et al.  Dissociation between running economy and running performance in elite Kenyan distance runners , 2015, Journal of sports sciences.

[5]  K. R. Williams,et al.  Relationship between distance running mechanics, running economy, and performance. , 1987, Journal of applied physiology.

[6]  Pierre-Marie Lepretre,et al.  Training and bioenergetic characteristics in elite male and female Kenyan runners. , 2003, Medicine and science in sports and exercise.

[7]  S. Marshall,et al.  Progressive statistics for studies in sports medicine and exercise science. , 2009, Medicine and science in sports and exercise.

[8]  A. Hackney,et al.  Anthropometrics and Body Composition in East African Runners: Potential Impact on Performance. , 2017, International journal of sports physiology and performance.

[9]  J. Mäestu,et al.  Better economy in field running than on the treadmill: evidence from high-level distance runners , 2014, Biology of sport.

[10]  G. Heise,et al.  "Leg spring" characteristics and the aerobic demand of running. , 1998, Medicine and science in sports and exercise.

[11]  T. Anderson Biomechanics and Running Economy , 1996, Sports medicine.

[12]  Jennifer L Caputo,et al.  Influence of gait manipulation on running economy in female distance runners. , 2008, Journal of sports science & medicine.

[13]  J Daniels,et al.  Running economy of elite male and elite female runners. , 1992, Medicine and science in sports and exercise.

[14]  Jacob Cohen The t Test for Means , 1977 .

[15]  Pui W Kong,et al.  Anthropometric, gait and strength characteristics of kenyan distance runners. , 2008, Journal of sports science & medicine.

[16]  G. Sleivert,et al.  Physical and Physiological Factors Associated with Success in the Triathlon , 1996, Sports medicine.

[17]  C. Nicol,et al.  Muscle–tendon interaction and EMG profiles of world class endurance runners during hopping , 2012, European Journal of Applied Physiology.

[18]  Nicholas Tam,et al.  Stride Angle as a Novel Indicator of Running Economy in Well-Trained Runners , 2014, Journal of strength and conditioning research.

[19]  K. R. Williams Biomechanics of Running , 1985, Exercise and sport sciences reviews.

[20]  T D Noakes,et al.  Are gait characteristics and ground reaction forces related to energy cost of running in elite Kenyan runners? , 2016, Journal of sports sciences.

[21]  J. Mäestu,et al.  Running economy and body composition between competitive and recreational level distance runners. , 2013, Acta physiologica Hungarica.

[22]  Andrew M. Jones,et al.  The Physiology of the World Record Holder for the Women's Marathon , 2006 .

[23]  Alejandro Lucia,et al.  Gait-cycle characteristics and running economy in elite Eritrean and European runners. , 2015, International journal of sports physiology and performance.

[24]  A. de Haan,et al.  Stride frequency in relation to oxygen consumption in experienced and novice runners , 2014, European journal of sport science.

[25]  Olivier Girard,et al.  Changes in leg spring behaviour, plantar loading and foot mobility magnitude induced by an exhaustive treadmill run in adolescent middle-distance runners. , 2015, Journal of science and medicine in sport.

[26]  K. R. Williams,et al.  The effect of stride length variation on oxygen uptake during distance running. , 1982, Medicine and science in sports and exercise.

[27]  J. Slawinski,et al.  Physical and training characteristics of top-class marathon runners. , 2001, Medicine and science in sports and exercise.

[28]  N. Caplan,et al.  Leg stiffness decreases during a run to exhaustion at the speed at O2max , 2014, European journal of sport science.

[29]  Veronique L Billat,et al.  Difference in mechanical and energy cost between highly, well, and nontrained runners. , 2004, Medicine and science in sports and exercise.

[30]  B. MacIntosh,et al.  Economy of running: beyond the measurement of oxygen uptake. , 2009, Journal of applied physiology.

[31]  T. Oda,et al.  Specific muscle–tendon architecture in elite Kenyan distance runners , 2014, Scandinavian journal of medicine & science in sports.

[32]  D. Lieberman,et al.  Effects of footwear and strike type on running economy. , 2012, Medicine and science in sports and exercise.

[33]  T. Keränen,et al.  Factors related to top running speed and economy. , 2007, International journal of sports medicine.