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Hydra Running for Recovery and Fitness

Hydra Running for Recovery and Fitness

By Gene Coleman, Ed. D., RSCC*E

Hydra running has been used by athletes in several sports to enhance recovery and maintain or improve fitness while avoiding the lower-extremity pounding that comes with land-based running.  Several track athletes have set personal best and/or World Records after deep water training and many MLB, NFL and NBA players have been able to return to competition earlier than expected after hydra training.

Hydra Running. There are two basic methods of hydra running, deep and shallow.  Deep running occurs in water over your head.  A flotation device is used to keep your head and shoulders above water as you run.  Shallow running occurs in waist-deep water at the shallow end of a swimming pool.  Both forms of training reduce the impact force associated with dry land running.

In shallow water running, the magnitude of the impact force is related to the depth of the water. The deeper the water, the greater the buoyancy and the less the impact force. At waist level, for example, the buoyancy force counter-acts approximately 50% of your body weight. The buoyancy force is equal to 75% and 90% of body weight at chest and neck level, respectively.1 In deep water, the feet do not touch the ground, the body is weightless and there is no impact between the feet and the bottom of the pool.

Deep-water exercise is relatively easy to do.  All you need is a pool at least 6-foot deep and a flotation device like ski vest or Aqua Jogger belt.  The water provides resistance on all sides of the body and the vest keeps your head above water so you can breathe. Because the body is surrounded by water, opposing muscles are forced to work equally and the movement of the arms and legs against resistance adds both cardiovascular and musculoskeletal stress to the body. Running in water also decreases joint stress and increases range of motion.2

For a more intense workout, try a scuba mask and snorkel.  The mask will keep water out of your eyes and the snorkel will allow you breathe under water.  Breathing under water increases the pressure on your thoracic cavity (makes it harder to raise and lower your ribs) and produces higher metabolic responses. Regardless of the equipment used, the movement patterns are identical.3 First, you assume a vertical position in deep water and then run without touching the bottom.

Use the same mechanics as when accelerating:

  • Bring your knee straight up with your heel under your buttocks and foot dorsi flexed.

  • Extend the opposite hip and leg

  • Move your arms from the shoulders.

  • Bring your lead hand inward toward the mid-line of your body up to cheek height.

  • Extend your opposite hand back past your pockets.

  • Run tall with your hips under your shoulders.

  • Don’t let your buttocks drift backwards.

  • Breathe naturally.

The variety of deep-water workouts is endless.  Any workout that you can do on a track, field or diamond can be simulated in the pool, which makes deep water running an effective substitute and/or alternative to running on land. Aerobic gains achieved with deep-water workouts are comparable to those with other forms of aerobic training. Because heart rate responses to work in water are lower than those on dry land, use a training heart rate that is 5-10% below that used on land.

Deep-water workouts can also be used to improve anaerobic fitness.  Do the workout equivalent to your land workout plus 25%.  If, for example, your land workout calls for a 20-minute workout, run 25-30 minutes in the pool.

Deep Water Workouts for Aerobic Capacity.

  1. Continuous Run.

  • Warm-up with a 5-minute jog.

  • Speed up until your heart rate is within 5-10% of that achieved on dry land.

  • Start with 10-15 minutes of activity and increase the duration by no more than 10% per week.

  • Build to 25-30 minutes of continuous exercise.

  1. Fartlek.

  • Fartlek is playing around with speeds. It’s unstructured which means you alternate moderate to hard efforts with easy efforts throughout the run.

  • For example, start with a 10-step jog (right leg – left leg is one step), followed by a 10-step sprint and finish with a 10-step jog.

  • Note: It’s easier to count arm movements than leg movements when counting steps.

  • Vary your sprint steps and jog steps for 20-30 minutes. For example, you might…

    • Jog 5 steps

    • Sprint 5 steps

    • Jog 5 steps

    • Sprint 10 steps

    • Jog 5 steps

    • Sprint 5 steps

    • Jog 5 steps

    • Sprint 15 steps

    • Jog 5 steps

    • Sprint 5 steps

    • Jog 5 steps

    • You can make up your program as you go.

Deep Water Workout for Speed.

Interval runs.

Assume that you can sprint ten yards in 10 seconds (10-second 100-yard sprint) in order to associate time and distance.  An all-out 5-second sprint, for example, is equivalent to a 50-yard dash.  A 10-second sprint is a 100-yard dash.  Use an interval-training format, alternating all-out sprints with slow recovery jogs.  Start with a 1:3 work to rest ratio.  That is, recover three times as long as you sprint.  Sprint three times per week on alternate days.  Switch to a 1:2 work-to-rest ratio after three weeks (Table 1).


Table 1. Deep-Water Speed Workout





5×5-sec sprint/15-sec jog

5×5-sec sprint/10-sec jog


5×10-sec sprint/30-sec jog

5×10-sec sprint/20-sec jog


5×15-sec sprint/45-sec jog

5×15-sec sprint/30-sec jog


5×20-sec sprint/60-sec jog

5×5-sec sprint/10-sec jog


5×15-sec sprint/45-sec jog

5×15-sec sprint/30-sec jog


5×10-sec sprint/30-sec jog

5×20-sec sprint/40-sec jog


5×5-sec sprint/15-sec jog

5×5-sec sprint/10-sec jog


  1. “Effect of gender, cadence, and water immersion on ground reaction forces during stationary running,” J Orthop Sports Phys Ther 2012;42(5):437–443, Epub 8 March 2012. doi:10.2519/jospt.2012.3572.

  2. Puelo, J. and P. Milroy. Running Anatomy. Human Kinetics, Champaign, IL, 2010.


Gene Coleman, Ed. D., RSCC-E, FACSM, was the Head S&C Coach for the Houston Astros (1978-2012) and strength and conditioning consultant for the Texas Rangers (2013-2020).  He is Professor Emeritus in the Exercise and Health Sciences Program at the University of Houston – Clear Lake and Website Education Manager

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