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The effect of plyometric training on distance running performance
European Journal of Applied Physiology
Volume 89, Number 1

Robert W. Spurrs, Aron J. Murphy, Mark L. Watsford
1Human Movement Department, School of Leisure, Sport and Tourism, University of Technology, Sydney, PO Box 222, Lindfield NSW 2070, Australia

Previous research has reported that plyometric training improves running economy (RE) and ultimately distance-running performance, although the exact mechanism by which this occurs remains unclear. This study examined whether changes in running performance resulting from plyometric training were related to alterations in lower leg musculotendinous stiffness (MTS). Seventeen male runners were pre- and post-tested for lower leg MTS, maximum isometric force, rate of force development, 5-bound distance test (5BT), counter movement jump (CMJ) height , RE, &Vitdot;O2max, lactate threshold (Thla), and 3-km time. Subjects were randomly split into an experimental (E) group which completed 6 weeks of plyometric training in conjunction with their normal running training, and a control (C) group which trained as normal. Following the training period, the E group significantly improved 3-km performance (2.7%) and RE at each of the tested velocities, while no changes in &Vitdot;O2max or Thla were recorded. CMJ height, 5BT, and MTS also increased significantly. No significant changes were observed in any measures for the C group. The results clearly demonstrated that a 6-week plyometric programme led to improvements in 3-km running performance. It is postulated that the increase in MTS resulted in improved RE. We speculate that the improved RE led to changes in 3-km running performance, as there were no corresponding alterations in &Vitdot;O2max or Thla.

Keywords : Plyometrics, Running economy, Musculotendinous stiffness, Distance running

The validity and reliability of a test of lower body musculotendinous stiffness
Andrew D. Walshe1 , G. J. Wilson1 and A. J. Murphy1

(1) Centre for Exercise Science and Sports Management, Southern Cross University, PO Box 157, 2480 Lismore, N.S.W., Australia

The aim of this study was to investigate the validity and reliability of an in vivo test of lower body musculotendinous stiffness. Male subjects (n = 23) with at least 12 months of weight training experience performed a series of quasi-static muscular actions in a supine leg press position during which a brief perturbation was applied. The resulting damped oscillations enabled each subject's maximal musculotendinous stiffness for the lower body musculature to be estimated. To assess the individual's capacity to benefit from active stretch, subjects also performed both a static jump and a countermovement jump. Statistical analysis revealed no significant different between day 1 and day 2 stiffness values (P < 0.01), an interday reliability ofr = 0.94 and a coefficient of variance of 8%. It was further demonstrated that maximal stiffness was significantly correlated to both isometric and concentric rate of force development (r = 0.50 andr = 0.54, respectively), and inversely related to the percentage difference between vertical jumps with and without prior stretch (r = − 0.54). Such results tend to suggest that the test is valid and are discussed with reference to the restitution of elastic strain energy, muscle potentiation and the interaction effects of elastic recoil on dynamic function. It was concluded that the assessment of stiffness of the lower body using the oscillation technique is a valid and reliable in vivo measure of musculotendinous stiffness.

Key words Series elastic component - Compliance - Rate of force development - Muscle elasticity