Optimising recovery post-game or post-training could provide a competitive advantage to an athlete, especially if more than one bout of exercise is performed in a day. Active recovery is one common method that is thought to enhance the recovery process. Another recovery method that is gaining popularity is water immersion. The objective of this thesis was to analyse whether these two recovery methods provided greater recovery from explosive exercise than passive recovery. A physiological rationale that may explain the possibility of enhanced recovery with water immersion was initially investigated. The literature surrounding active recovery, water immersion and passive recovery on strength, cycling, running and jumping was then examined. Following these reviews an experimental study was conducted investigating the effects of water immersion, active recovery and passive recovery conducted after repeated bouts of explosive exercise. The rationale for active recovery post-exercise is that during intense exercise, fluid from the blood is forced into the working muscles due to the increase in mean arterial pressure, which increases muscle volume and decreases blood plasma fraction. Active recovery reduces this exercise induced edema and, with an associated increase in blood flow throughout the body, may increase the metabolism of waste substrates produced during exercise. Researchers have observed this increased substrate metabolism with reductions in post-exercise blood lactate accumulation following active recovery. Water immersion would appear to cause a similar physiological response to active recovery without the need to expend extra energy. When a large portion of the body is immersed, hydrostatic pressure acts on the body's fluids within the immersed region. Fluids from the extravascular space move into the vascular system reducing exercise-induced increases in muscular volume and reducing soft tissue inflammation. Additionally, blood volume increases and is redistributed towards the central cavity, which in turn increases cardiac preload, stroke volume, cardiac output, and blood flow throughout the body. Cardiac output increases in relation to the depth of immersion and have been observed to increase by as much as 102% during head-out immersions. These cardiovascular responses occur without any increase in energy expenditure. If extra-intravascular fluid movement is enhanced, then the movement and metabolism of waste substrates could increase. Observations of increased post-exercise blood lactate clearance with water immersion would support this theory. Most methodologies studying the performance benefits of active recovery and water immersion suffer many limitations. These limitations often consist of the experimental time schedule not replicating what is likely to occur in a practical situation, no isolation of water temperature and hydrostatic pressure effects, and lack of a sport-like exercise consisting of repeated expressions of explosive power. Light-intensity active recovery and water immersion do not appear to be detrimental to performance, but neither does there appear to be enough evidence to claim they are beneficial. Effects of active recovery and water immersion would seem to be trivial to small, with any benefits more likely following multiple bouts of high-intensity exercise and recovery or following muscle damaging exercise. There may be a link between blood plasma fraction and performance, however, evidence is inconclusive. Given these issues and limitations the aim of this research was to investigate whether combinations of active recovery, water immersion and passive recovery could maintain peak power and work during subsequent bouts of explosive exercise. We also investigated whether there was any difference in subjects' blood plasma faction and perceived fatigue between the recovery modes. A cross-over experiment was conducted on seven subjects over four weeks. On the same day of each week subjects performed three sessions of maximal jumping, each two hours apart, followed by a different recovery method. Each jump session consisted of three sets of 20 maximal jumps repeated every three seconds, with a minute's rest in-between. Immediately following the jumping subjects performed 10 minutes of either (A) active recovery on a cycle ergometer followed by seated rest, (I) immersion to the gluteal fold in 19°C water followed by seated rest, (AI) active recovery followed by immersion, or (P) seated passive rest. Jumping was conducted on an instrumented supine squat machine that allowed the measurement of total peak power and total work. Pre-jump, post jump and post-recovery blood was taken and the percentage of blood plasma fraction calculated. Perceived leg fatigue was also measured at these times. Observed differences in total peak power and total work between the recovery modes were non-significant. No differences were observed in the change of blood plasma fraction between the recovery modes or perceived fatigue. One reason for any lack of difference between the recovery modes may have been the brevity of the recovery time. Research that has observed significant benefits of active recovery and water immersion compared to passive recovery have used recovery times greater of 15 minutes or more. Additionally, changes in blood plasma fraction between active recovery, water immersion and passive recovery have not been apparent until at least 10 minutes post-recovery in previous research. Alternatively, rather than brevity, it may be that active recovery or water immersion simply does not provide any benefit to performance recovery. Overall there is a meagre amount of research into active recovery, water immersion and passive recovery. Further research that incorporates a variety of exercise and recovery protocols is required.

"February 2004" / Bibliography: leaves 168-188. / xvii, 194 leaves : ill. ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, School of Molecular and Biomedical Science, Discipline of Physiology and Dept. of Obstetrics and Gynaecology, 2004?

Graduation date: 1992

Introduction: Recent reports in exercise related bone research have shown increased bone mineral content (BMC) at the femoral neck for prepubescent children participating in exercise programs consisting of repeated drop landings from a height of 61 cm. Increases in BMC from this type of exercise are believed to be the result of both high rate and magnitude of loading at the proximal femur. However, the dynamic characteristics associated with these landings in children have not been studied. Purpose: To describe the dynamic characteristics of children during landing and to quantify the forces associated with an activity associated with increases in bone mass. Methods: 13 prepubescent children (males=8, females=5, age 9.3 �� 0.7 years) who had previously completed drop landings over a 7 month period as part of an exercise intervention to increase bone mass participated in this research. Each subject performed 100 drop landings onto a force plate from a height of 61 cm. Ground reaction forces and two-dimensional kinematic data were recorded. Hip joint reaction forces were calculated using inverse dynamics based on a four segment rigid body model. Vertical ground reaction force and displacement data were fit to two single degree of freedom models, the Voigt and standard linear solid (SLS). The goodness of fit was quantified using the standard deviation of the error (SDE) between the experimental and the predicted data. Results: Peak vertical ground reaction forces were 8.5 �� 2.2 (mean �� SD) body weights (BW) while hip joint reactions were 6.0 �� 1.8 BW. Loading rates for ground reaction forces during initial impact were in excess of 470 BW/s. Across 100 jump trials, ground reaction forces changed significantly for 5 subjects (4 increase, 1 decrease, p<0.05) but were unchanged as a group. The SLS and Voigt models replicated the displacement traces well (SDE=0.003 m and 0.001 m respectively). However, in fitting force data, the SLS outperformed the Voigt model (SDE=580 N and 493 N respectively), but slightly under-predicted peak forces by 13%. Conclusion: Comparing force characteristics from drop landing to force characteristics known to be osteogenic, we can see how drop landings contribute to the osteogenic stimulus. The models used to represent children during drop landing closely fit displacement data, but did not replicate the time history of the impact force peaks thought to be important to osteogenesis. Quantification of exercises known to increase bone mass provides a basis on which to develop and implement additional exercise interventions for the purpose of increasing bone mass. / Graduation date: 2000

Graduation date: 2000

Graduation date: 1999

Given the high risk of relapse during the first year of exercise involvement, it is important to determine the processes of self-motivation which enable novice exercisers to become long-term maintainers. This study was designed to extend previous Stages of Change (Prochaska & DiClemente, 1983) research by comparing the Possible Selves (Markus & Nurius, 1986) of individuals at different points within the Maintenance stage of exercise. Participants consisted of female university employees, spouses, and dependents age 35-59 years who volunteered for the study. Participants completed the Stage of Exercise Scale (SOES; Cardinal, 1995) and a self-administered form of the Possible Selves Inventory (Cross & Markus, 1991) which was adapted to address the exercise domain. Women classified by the SOES as being in the Maintenance stage of exercise V=92) were assigned to one of three groups based on the duration of their exercise maintenance (6 months-5 years, 6-10 years, and 11-20 years). The three maintenance groups were compared with regard to the number and category of open-ended and exercise-related possible selves and the self-efficacy and outcome expectancy associated with three focused selves (most important, exercise-related, and exercise-specific). The results indicated that the three maintenance groups did not differ significantly in their possible selves. These findings provide support for the current conceptualization of the Stages of Change Model (Prochaska & Di Clemente, 1983) and suggest that differences between novice and expert maintainers may be behavioral, rather than cognitive, in nature. Several implications for intervention design and suggestions for future research are discussed. / Graduation date: 1998

Graduation date: 1994

This investigation examined the influence of two levels of dietary sodium (Na+) intake on intramuscular and extracellular potassium (K+) content. Nine unacclimatized college males exercised. (90 minutes of treadmill walking, 5.6km/hr, 6X grade) in an environmental chamber maintained at 40.1( + .05)°C and 23.5( + . 4) %RH, during two 8-day dietary-acclimation regimens. The first regimen employed a high Na+ diet (399mEq/day), the second a low Na+ diet (98mEq/day); both diets contained 80mEq K+/day. Total body K+ stores increased during the high Na+ diet (+138mEq, 4.1%) and the-low Na+ diet (+114mEq, 3.4%). By day 8 (D8) of both treatments, subjects exhibited a significantly lower (p<.O5) mean heart rate and rectal temperature. Oxygen consumption and sweat rate were unaltered but sweat responsiveness (ml/hr/°c) progressively increased during the acclimation trials. Plasma volume increased +16.3% (D4) and +10.7% (D8) under the high Na+ diet and only +3.0% (D4) and +7.0% (D8) under the low Na+ diet. The low sodium diet was associated with a significantly higher (p<.05) mean heart rate (D3-D5), higher rectal temperature (D3-D6), lower sweat responsiveness (D2) and a delayed plasma volume expansion (D4)--resulting in less effective heat removal. The total content of K+, Na+, and C1- in plasma changed isoosmotically with plasma volume. The diets were associated with equivalent urine K+ excretion, and. during exercise in the heat both diets resulted in significantly decreased urine K+ losses. Muscle K+ and sweat K+ concentrations were not altered by dietary intervention or acclimation trials. Total muscle water-was significantly increased, in accord with Na+ and Cl- increases, on D8 of the low Na+ diet only. It was concluded that dietary intake of Na+, in combination with 8 days. of exercise in the heat and heavy sweating, does not significantly diminish the intramuscular K+ or total body K+ content.

Graduation date: 1994