Pool running, often called aqua jogging or deep water running, involves simulating the running motion while fully submerged in the deep end of a pool, ensuring the feet do not touch the bottom. This method is an effective form of cardiovascular exercise that allows for the maintenance of fitness without the physical trauma associated with land-based running. The primary utility of this training is its capacity to reduce stress on joints while still providing a robust aerobic workout. Deep water running is a successful tool for injury recovery, cross-training, and increasing overall training volume.
The Core Advantage: Low Impact, High Resistance
Deep water running’s effectiveness stems from the physics of the aquatic environment: buoyancy and resistance. When immersed up to the neck, the upward force of buoyancy reduces a person’s body weight by approximately 90%, virtually eliminating the impact forces that occur with every stride on land. This non-weight-bearing state makes the exercise ideal for athletes recovering from stress fractures or lower-body joint injuries, as it removes compressive forces on the musculoskeletal system.
Water provides significantly more resistance than air due to its viscosity. Moving through water offers between 12 and 40 times the resistance of moving through air, depending on the speed and surface area of the movement. This constant drag resistance means that muscles are engaged dynamically throughout the entire range of motion, providing both concentric and eccentric loading. The increased resistance against movement turns a cardiovascular workout into a full-body conditioning session, promoting muscle tone and strength.
The third physical factor is hydrostatic pressure, exerted equally on all submerged surfaces. This external pressure can help reduce swelling and edema in the extremities, which is beneficial for post-injury recovery. Furthermore, the pressure on the chest and respiratory muscles slightly increases the work of breathing, which can strengthen these muscles over time.
Technique and Equipment for Effective Pool Running
A flotation belt or vest is necessary to maintain an upright position without constantly treading water. This equipment keeps the head above the water surface and is the preferred choice over a vest, as it typically allows for a more natural arm swing. Maintaining proper form is essential to maximize the resistance and training benefits of the water.
The correct posture involves keeping the body tall and vertical, with the head up and the shoulders relaxed, avoiding the common mistake of leaning too far forward. The leg motion should simulate land running, focusing on a quick, short stride and a high cadence. Think about driving the knee upward to about a 70-80 degree angle at the hip before pushing the foot straight down and slightly back against the water.
The recovery motion is equally important; the foot should be pulled quickly toward the glutes before the knee drives forward again. This cycling motion, performed with a fast turnover, ensures that the leg is constantly working against the water’s resistance instead of simply floating. Using a loose fist and swinging the arms in a natural, pendulum-like motion, similar to land running, helps maintain balance and contributes to the overall propulsion.
Comparison to Land Running: Training Differences
Deep water running provides a powerful aerobic workout, but a few physiological differences exist when compared directly to land running. Due to the cooling effect of water and the hydrostatic pressure pushing blood inward and upward, the heart is able to pump more blood per beat, increasing cardiac output. This enhanced efficiency causes the heart rate to be significantly lower, typically 10 to 15 beats per minute less than a land-based run at the same level of perceived effort.
Because of this heart rate difference, athletes should rely on the Rate of Perceived Exertion (RPE) scale rather than heart rate monitors to gauge the intensity of their water workout. While deep water running successfully maintains cardiorespiratory fitness, it does not perfectly replicate the muscle specificity of land running. Studies show that while activity in the hamstrings and quadriceps can be similar to land running when matched for heart rate, the muscle activity in the calf (gastrocnemius) is significantly lower, decreasing by 34% to 48%.
This reduction in calf muscle activity is related to the absence of the specific ground reaction forces and the elastic energy return involved in pushing off the ground. While deep water running is an excellent form of cross-training and maintains aerobic capacity, it will not build bone density like land running. The training is best used by injured athletes looking to maintain fitness, individuals seeking a low-impact cardio option, or runners adding low-stress mileage to their weekly training volume.