The relationship between leg stiffness, range of motion and performance in active females A. Murphy*, C. Hickson, A. Coutts & S. Rees University of Technology, Sydney
Previous research suggests that leg stiffness influences jump and sprint performance in male athletes, although the mechanisms are not completely understood. Currently the relationship between these variables in female athletes is unknown. As such, the aim of this study was to examine the relationship between range of motion (ROM) and stiffness, and the association between these musculotendinous properties and performance. This study investigated the musculotendinous stiffness and performance of 22 active females (Age 20.8+1.gyrs; Mass 63.7+7.9kg; Height 164.8+5.6cm). Tests assessed included sprint speed over 30m, drop jump, countermovement jump, isometric strength of the plantar-flexors, maximum ankle ROM and leg musculotendinous stiffness using a hopping task. Pearson's correlations showed ankle ROM and unilateral leg stiffness were significantly related (r=0.51-0.73). ROM of each leg was not correlated with bilateral leg stiffness, demonstrating the need to assess stiffness of unilaterally. Additionally, no measures of ROM were significantly correlated with any of the performance variables. With regard to sprinting, unilateral leg stiffness demonstrated a significant negative correlation (r=-0.500.55; p<0.05), although low, this suggests that subjects with greater stiffness had a faster sprint velocity over 30m. Bilateral leg stiffness was not correlated with any performance measure, and unilateral stiffness measures showed no association to any jump performance. Our results showed that unilateral leg stiffness significantly influences sprint, but not jump, performance in active females. In addition, the results clearly demonstrate that unilateral stiffness measures are preferable as compared to bilateral measures which showed no relationship to performance or flexibility measure. The relationship between passive flexibility and leg stiffness is also discussed.
Physiological and performance benefits of halftime cooling D. Hornery*, S. Papalia, I. Mujika & A. Hahn University of Western Sydney / AIS,
Objectives: This study examined the effect of a 10 min, halftime cooling application on physiological and psychological parameters known to affect performance. Methods: Fourteen volunteers (10 male, 4 female) completed two randomised trials 48 hr to seven days apart. Each trial consisted of a 1 hr cycling protocol: 30 min at 75% VO2max followed by 10 rain cooling (application of a cooling jacket) or passive recovery (control), and a second 30 rain exercise bout consisting of 20 min at 75% VO2max, immediately followed by a 10 min maximal effort, where work was measured as energy expended (KJ). Results: Performance of the 10 min maximal intensity phase tended to improve (171.54 + 30.38 KJ vs 165.38 + 29.17 KJ, p = 0.087) and sweat loss decreased marginally (1479.43 + 532.04 ml vs 1512.07 + 496.08 ml, p = 0.22), following the cooling trial. Heart rate during the 5th rain of the maximal effort, (182.5 + 8.57 bpm vs 179.71 + 7.37 bpm, p = 0.024), blood lactate concentration at 6 min post exercise (9.3 + 3.1 mmol vs 7.9 + 3.2 mmol, p = 0.007), rating of perceived exertion at the 20th rain post halftime recovery (15.35 + 1.95 vs 16.43 + 2.34, p = 0.042), and subjective rating of feelings and emotions differed between the cooling and control conditions. Core and mean skin temperature and rating of thermal sensation also tended to be different between conditions, but differences were non significant. Conclusions: Halftime cooling resulted in greater aerobic performance and decreased the likelihood of reaching exhaustion through dehydration. This study revealed that individuals perceived themselves inherently more capable of performing submaximal intensity exercise following short duration cooling. However, the cooling intervention failed to induce any significant thermoregulatory effects. 108