By Joe Giandonato, MBA, MS, CSCS
Among the numerous exercise modalities studied, practiced, and employed within the fitness industry, aquatic exercise / pool exercises and the cadre of benefits it boasts, is often overlooked by fitness professionals.
According to a 2013 report furnished by the Sports and Fitness Industry Association entitled “Sports, Fitness, and Leisure Activities Topline Participation”, 9,177 people out of 42,365 respondents or 22%, indicated participation within aquatic exercise at least one time in the past year. Per the IHRSA 2018 Health Club Consumer Report, a biennially conducted survey, showed an increased participation rate of 5% in aquatic exercise.
The utility of aquatic exercise and its far reaching health and performance boosting benefits, especially during the COVID-19 pandemic that continues to rage on in conjunction with the onset of flu season in geographic locales throughout the United States and the rest of the world, should be given closer consideration for acceptance within a comprehensive fitness program.
Aquatic exercise has traditionally been promoted for adoption among aging populations, those with cardiovascular disease, and injured persons.
The inclusion of aquatic exercise demonstrated significant improvements in balance and postural mobility while simultaneously reducing risks of falls — a self-limiting phenomenon that inhibits motor learning — among overweight older adults (4). Aquatic exercise was also found to diminish lower back pain among obese women pursuant to 60-minute sessions performed twice weekly over a 12-week period (1). When conjoined with traditional resistance training modalities, regular engagement in aquatic exercise was found to simultaneously improve joint stabilization, core muscles, muscular strength, and range of motion among those suffering from knee pain (2).
Paralleling improvements in cardiovascular health were realized following a similar protocol in which twice weekly aquatic exercise sessions were paired with traditional resistance training or aerobic exercise for a period of 16-weeks, which evoked decreases in both resting systolic blood pressure (-6.53 mmHg to -10.73 mmHg) and diastolic blood pressure (-4.61 mmHg to -6.23 mmHg) (7). Moreover, 20% of the study’s participants shed their hypertensive classification.
In comparison to more common forms of exercise on land such as resistance training and cardiovascular exercise, whether performed via machines or on ground, aquatic exercise promotes venous return, in turn decreasing risk of circa exercise cardiac event, owing to the hydrostatic forces which impact cardiovascular hemodynamics, or blood flow, centrally and temporally.
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The buoyant nature of water also affords the ability to move safely and perhaps more quickly as bodyweight, gravity, and combined ground reaction forces or landing impacts, that are linked with walking, jogging, and running are mollified.
Among sedentary individuals with no reported health or medical issues, the regular execution of three aquatic exercise sessions over five weeks consisting of an assortment of calisthenic and ballistic exercise performed in high intensity interval training or HIIT fashion hallmarked by timed bouts of exertion and punctuated with proportionate rest periods, resulted in distinctive improvements in cardiorespiratory fitness and exercise economy (6). Additionally, moderate body composition improvements, via reductions in body fat, were aggregated post-training.
Similar to its land-based exercise modality and programming counterparts, aquatic exercise has shown improvements in neurocognition via the secretion of brain derived neurotrophic factor or BDNF (4), a gene that plays integral roles in encoding learning activities and stewarding memory.
Aquatic exercise has also demonstrated utility in helping manage chronic respiratory diseases and is recommended for those with chronic obstructive pulmonary disease (COPD) since appreciable exercise intensity can be achieved absent of stabilization demands that prove challenging for those who are overweight or obese and/or have musculoskeletal injuries that restrict mobility and balance. Extrapolating from its beneficial impact on lung function, preliminarily speaking, aquatic exercise could serve a valuable complimentary role to respiratory therapy treatments for patients with residual lung damage from COVID-19.
Moreover, aquatic exercise could be a safer alternative than traditional forms of exercise transpiring in fitness and recreation facility settings as any virus shed in pool water will likely be deactivated by regular chlorination. To date, there is no evidence linking COVID transmission through pool water, however, the virus can be spread through respiratory droplets and physical contact, where bodily fluids containing the live virus can enter ACE-2 receptors within the mucous membranes and sweat glands respectively.
Within the water, exercise intensity can be easily progressed or regressed, much like external loads associated with training with barbells and dumbbells. One must simply change the depth of water in which they are standing to manipulate the water’s buoyancy factor. Water at neck depth will reduce the body’s weight by 90%; at chest depth, 75%; at waist depth, 50% and lastly at knee depth 10-15%.
And while the application of the law of gravity will be rendered nearly moot in a buoyant environment, one can elicit a training effect by ascribing to other foundational laws of physics: the laws of inertia, acceleration, and action.
The law of inertia states that an object will remain at rest unless acted upon by an outside force.
For example, a person wading in the ocean near the water’s edge as waves crash ashore. The waves surging towards the coastline and the related pull back or “undertow” thrust and pull one’s body in multiple directions. If you do not actively try to resist the pull back or brace yourself against or hurdle oncoming waves, you’ll sink and get pulled out to sea.
Inertia can be created by a person in the water by performing several different movements. Now, that person must absorb the forces, or “mini currents”, that were created by those said movements, without harsher gravitational forces acting upon the body and its musculoskeletal system.
Acceleration refers to the extent of effort and rapidity to which its applied.
For example, a person wading through still water or water walking in shallow pool will not be applying force requisite to produce splashes as they run through the water or propel forward as they bound from the pool’s surface. Accelerating quickly whether in the water or on dry ground, requires a swift recruitment, synchronization, and discharge of motor neurons that innervate swaths of muscle fibers to produce fast or explosive movement. Movements which are more explosive are more metabolically demanding and confer greater calorie burning effects [calories in a shorter period] via post-exercise oxygen consumption or EPOC.
Finally, the law of action states that for every action there is an equal and opposite reaction.
An example of this would be running in the water or swimming in one direction and quickly reversing course, going against the flow of the water.
In any case, one or a combination of these laws, like the depth at which exercises are performed, can be manipulated to produce a desired training effect. Additionally, weights, cotton towels, which can hold up to 27 times their weight in water, sponges, and empty PVC pipes can be used as resistance tools to make exercises more challenging. Alternatively, exercises can be performed supported against the wall or handrails or assisted via floatation devices, such as “pool noodles” and rafts. Below are exercises and water depths arranged from easiest to most difficult that could be selected to compliment a traditional resistance training program or for those rehabilitating from injury or illness, a sufficient stimulus from which strength and lean body mass can be built.
Novice / Easy (performed at shoulder to neck depth)
- Lap Walking
- High Knee Hug
- Cradle Walk
- March with Arm Swing and Opposite Leg Knee Drive
- Lateral Walk
Intermediate / Medium (performed at chest to shoulder depth)
- Walk with Press / Punch [along surface of water]
- Alternating Straight Legged March
- Pogo Jumps (two legged)
- Pogo Jumps (one legged)
- Side to Side Hops (two legged)
- Side to Side Hops (one legged)
- Linear Bounding (take off from one leg and land with opposite leg)
- Lateral Squat Walk
- Lateral Leg Swing
- Shoulder Abduction [along or slightly beneath surface of water]
- Shoulder Adduction [along or slightly beneath surface of water]
- Underwater Shadow Boxing [with head and top of shoulders remaining above water]
- High Knees
- Butt Kicks
- Knee lifts
Advanced / Difficult (performed at waist depth)
- Stationary Lunge
- Reverse Lunge
- Walking Lunge
- Stationary Lateral Lunge
- Resisted Squat [with PVC Pipe, water weights, or water-soaked cotton bath or beach towel)
- Resisted Squat to Press [with PVC Pipe, water weights, or water-soaked cotton bath or beach towel)
Advanced / Difficult (performed at knee to mid-thigh depth)
- Water Resisted Sprinting and Change of Direction Activities
Singular bouts of exertion involving water resistance exercise evoked heightened perceptions of effort peri-exercise and an increase in delayed onset muscle soreness or DOMS in comparison to sprinting on-ground (3). It is theorized that sprinting and running in shallow water (i.e. with the lower body submerged in close proximity to the water’s edge can strengthen the musculature of the lower body, particularly the hip flexors, which will result in increasing acceleration and sprint velocity.
In any case, fitness professionals should weigh the feasibility and potential risks and benefits of specific aquatic exercises and more broadly, aquatic fitness modalities.
Until next time…
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- Abadi, F.H., Sankaravel, M., Zainuddin, F.F., Elumalai, G., & Razli, A.I. (2019). The effect of aquatic exercise program on low-back disability in obese women. Journal of Exercise Rehabilitation, 15 (6), 855-860.
- Assar, S., Gandomi, F., Mozafari, M., & Sohaili, F. (2020). The effect of total resistance exercise versus aquatic training on self-reported knee instability, pain, and stiffness in women with knee osteoarthritis: a randomized control trial. BMC Sports Science, Medicine, and Rehabilitation, 12 (27).
- Cook, S.B., Scarneo, S.E., & McAvoy, R.M. (2013). Physiological effects of an acute bout of shallow water sprinting. International Journal of Aquatic Research and Education, 7 (2), 105-115.
- Irandoust, K., Taheri, M., Mirmoezzi, M., H’mida, C., Chtourou, H., Trabelsi, K., Ammar, A., Nikolaidis, P.T., Rosemann, T., & Knechtle, B. (2019). The effect of aquatic exercise on postural mobility of healthy older adults with endomorphic somatotype. International Journal of Environmental Research and Public Health, 16 (22), 4387.
- Kang, D., Bressel, E., & Kim, D. (2020). Effects of aquatic exercise on insulin-like growth factor-1, brain derived neurotrophic factor, vascular endothelial growth factor, and cognitive function in elderly women. Experimental Gerontology, 132.
- McDaniel, B.B., Naquin, M.R., Sirikul, B., & Kraemer, R.R. (2020). Five weeks of aquatic-calisthenic high intensity interval training improves cardiorespiratory fitness and body composition in sedentary young adults. Journal of Sports Science and Medicine, 19 (1), 187-194.
- Reichert, T., Costa, R.R., Barroso, B.M., de Mello Bones da Rocha, V., Oliveria, H.B., Bracht, C.G., de Azevedo, A.G., Kruel, L.F.M. (2020). Long-term effects of three water-based training programs on resting blood pressure in older women. Journal of Aging and Physical Activity, 1-9.