The Physiology of Deep Water Running

1. The Physiology of Deep Water Running Dr. Moran EXS 558 November 16, 2005

2. Lecture Outline • Introduction • What is the purpose? USES • Research Interest  9,470 hits in Google Scholar for deep-water running • Cardiorespiratory Responses to Water Immersion • Blood Compartments • Cardiovascular • Lung Function • Physiological Response • Maximal exercise • Sub-maximal exercise • Longitudinal Studies “The Physiology of Deep Water Running” Journal of Sport Sciences Reilly et al. (2003)

3. Uses • Why deep-water running? • Injury prevention • Decreased compressive forces on spine (Dowzer et al., 1998) • Decreased lower back injuries within a running population • Reduced musculoskeletal loading as compared to over-ground running • Rudzki & Cunningham (1999): with the introduction of deep-water running a total reduction of injury of 46.6% in military recruits

4. Uses • Recovery • Recommended for accelerating the recovery rate in between soccer games (Cable, 2000) • This has not been scientifically proven • Reilly et al. (2001) • Examined the role that deep-water running had on preventing delayed-onset-muscle-soreness (DOMS) • Deep-water running (DWR) failed to prevent DOMS but appeared to speed the process of recovery for leg strength and perceived soreness • Leg strength was reduced 20% 48hr post-activity w/o DWR but 7% with DWR

5. Uses (con’t) • Health-Related Exercises • Recommended for people with orthopedic injuries • Cardiovascular Training • Overweight People • Takeshima et al. (2002) • Women aged 60-75 had improvements in: 1.) Knee extension strength 2.) Chest Press 3.) VO2 Max 4.) Vertical Jump 5.) Shoulder Press

6. Uses (con’t) • Ancillary Training • Endurance athletes attempting to increase training volume without the associated pounding on musculoskeletal system • Summary of Uses

7. Cardiorespiratory Response Water Immersion • Blood Compartments • Hydrostatic Vascular Gradient • Contributes to increased central blood volume because of adjusted intrathoracic pressure relative to surrounding water • Pressure imbalance • Between thoracic cavity and alveolar spaces • Creates a 700ml redistribution of blood volume to the central circulation with the heart accepting about 200ml of that (Arborelius et al. 1972) The effect of graded immersion on heart volume, central venous pressure, pulmonary blood distribution, and heart rate in man. Risch et al. (1977)

8. Cardiovascular Response • Cardiac Output • ↑ 30-35% when an individual at rest is immersed in water • Obviously creates an improved end-diastolic volume (EDV) • Peripheral Vascular Volume (PVV) • Hydrostatic pressure of tissues causes transcapillary fluid shift leading to a ↓ in PVV • Thus, an ↑ with thoracic blood volume  stretch of heart walls • Christie et al. (1990) • left-ventricular end-systolic (30% ↑ ) and end-daistolic pressure greater in water than on land

9. Cardiovascular Response (con’t) • Stroke volume higher for any exercise intensity while submerged as opposed to on ground • Possible reasons: • Displacement of peripheral blood volume to central core area • Does this affect O2 delivery? • Left ventricular EDV is close to maximum at rest eliminating the chance for it increase with more intense exercise • Cardiac filling time is reduced • Cause of increased stroke volume • Enhanced pre-load (Frank-Starling mechanism) • NOT b/c of enhanced ventricle emptying

10. Alterations of Lung Function • Reduce action of inspiratory muscles • Because of hydrostatic pressure compressing the diaphragm • Reduced lung capacity and vital capacity(def: the volume change of the lung between a full inspiration and a maximal expiration) • 3-9% (Hong et al., 1967) • The level of immersion will affect the amount of reduced pulmonary action • Functional residual capacity declines only slightly in immersion up to the hip, but 400ml when immersed to the xiphoid and another 400ml when immersed to the neck (Farhi et al., 1977)

11. Physiological Response to DWR • VO2 max • Consistently reduced when DWR is compared to running on a treadmill • Questionable methods • Short duration of DWR protocols • Rely on participants to increase exercise based on RPE • Failure to reach true maximum? • Dowzer et al. (1999) • Peak Oxygen Uptake • Shallow Water Running (SWR)  83.7% VO2 Max • DWR  75.3% VO2 Max • Peak Heart Rates • SWR  94.1% of max HR • DWR  87.2% of max HR

12. Muscle Recruitment Changes? • Michaud et al. (1995a) • a greater % of work in water performed by upper extremity • Upper arm action may be needed to aid in buoyancy • This could explain the reduced VO2 max found from DWR

13. Reduced HR During DWR • No clear consensus on what causes a reduced HR while DWR • Possible Mechanisms • Baroreflex-mediated decline in HR during rest in water temp below thermoneutrality • Enhanced venuous return and cardiac pre-load • Cardiac Output = HR x SV • Reduced sympathetic neural outflow from an altered baroreceptor activation

14. Respiratory Exchange Ratio • RER = (volume of CO2)/(volume of O2) • DeMaere and Ruby (1997) • DWR induced a higher RER ration indicating an increased reliance of carbohydrate oxidation and decreased lipid (fat) utilization

15. Summary of DWR Reilly et al. (2003)

16. Longitudinal Studies