pool-based rehab_ a complete guide _ sports injury bulletin

4/9/2014 Pool-based rehab: a complete guide | Sports Injury Bulletin

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Pool-based rehab: a complete guide

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"Pools are excellent environments in which to train water provides buoyancy and

resistance properties that allow the individual to undertake exercise with minimum

impact on the body."

Angela Calder (performance consultant for Australian Institute of Sport)

If the pool is such a great training environment, why does it not feature far more prominently in ourathletic clients rehabilitation and recovery sessions? Although the extent to which pool training is usedwill vary from country to country , the unavoidable reality is that most sports support professionals failto use water workouts as a rehab tool for one simple reason: ignorance.

That was certainly true in my case 10 y ears ago, when I started working at the Sports Injury andRehabilitation Centre in Lilleshall, central England. Up until then Id only ever gone to the pool to swim,play on inflatables and do some top bombing from the div ing boards. At Lilleshall I had my firstexposure to pool-based training as part of the rehabilitation programme for footballers receiv ingtreatment at the centre. Even then, it didnt occur to me that y ou could also use the pool as a trainingtool when y ou werent injured. It wasnt until I started working with the England netball team that I wasexposed to the use of the pool in this way .

With the help of the team coach and Marques Church, a clever strength and conditioning coach fromNew Zealand, who shared all his knowledge with me, I soon started to include a wide range of pool-based training in my athletes programmes. Ten y ears on, I have learned a great deal about how waterworkouts can improve body alignment, aerobic and anaerobic fitness, flexibility , strength and overallbalance and coordination, and I still use the pool with my athletes for training, recovery andrehabilitation. Below I set out some of the applications and drills I have found invaluable over they ears.

To be able to use the pool effectively , y ou must first understand a little about the properties of water,the effect of water immersion on phy siology and how both of these things affect our movement andfunction.

Key properties of water

Buoy ancy : The term used to describe a fluid force that alway s acts vertically upwards. It was, of course,the Greek mathematician Archimedes who first worked out the magnitude of a buoy ant force in hisfamous principle: the buoy ant force acting on a body is equal to the weight of the fluid displaced by thebody (1 ,2,3). Buoy ancy is helpful in training because it enables the water to support the body , which isparticularly useful during rehabilitation from injury . Y ou can also increase an athletes buoy ancy withthe aid of floatation dev ices such as belts and vests.

Hy drostatic pressure: In a fluid, this increases with depth, and is applied over the surface of anyobject immersed in the fluid(1 ,2). This turns out to be another valuable property in rehabilitation: theincreased pressure on the body can be used to reduce swelling and allow the athlete to exercise aninjured limb without the risk of aggravating swelling.

Fluid dy nam ics (flow): When an object such as a human hand moves slowly through water, there islittle apparent disturbance around the hand. As the speed of movement increases, waves and eddies arecreated(1 ,2). Two different ty pes of flow exist: l laminar, characterised by smooth lay ers of fluidmolecules flowing parallel to one another l turbulent, characterised by a mixing of the lay ers of fluidmolecules.

In pool training, we can alter the fluid dy namics to change the intensity of the training session. If theathlete maintains a streamlined shape, they will produce minimal disruption to flow. But when theyadopt an unstreamlined shape or use an unstreamlined object such as a float, they will disturb flow andincrease drag, which ups the intensity of the movement.

Depth: T here is an inverse relationship between water depth and the am ount of bodyweight supported by the m usculoskeletal sy stem . When y ou stand on the bottom of thepool im m ersed up to y our neck, y our body is bearing about 8% of its weight. Drop thewater level to around m id chest and the body bears 28% to 35% of its weight, increasing to



47 % to 54% at waist height (see T able 1, below)(4). So by changing the level of the body inthe water y ou can increase or decrease loading on the m usculoskeletal sy stem , which isvery useful for rehab and injury prevention. Bear in m ind, though, that the values inT able 1 reflect static weight bearing: if y our athlete is bouncing up and down, lifting arm sabove their head etc, the loading values will increase proportionate to the am ount of thebody out of the water.

How the body behaves in water A body in water produces a different phy siological response tohow it behaves on dry land, so it is essential that the therapist or coach understands the key differences.Cardiovascular sy stem Respiratory function decreases, because of increased pressure on the thoraciccav ity . We lose up to 9% of our v ital capacity (total volume of air forcefully expired after maximalinspiration)(5). The rate at which we breathe increases, but sub-maximal and maximal heart rates tendto be 8% to 10% lower (10-20bpm) than on dry land(6). Maximal oxy gen uptake values (VO2max) candecrease by around 17 % (5,7 ,8) although this does not affect y our ability to use water-based trainingto improve y our athletes VO2max (see below). Note, however, the importance of the correct watertemperature: warm water can increase cardiovascular demand over and above the demands ofexercise. One study (9) found that cardiac output increased significantly at 40C compared to 25C or34C. The study also noted that at 36C the centralisation of peripheral blood flow was overcome by thethermal stimulus to increase heart rate. The message here is that y ou do not want to put an athlete intoa pool for an intense training session if the temperature is greater than 28C because of the increased riskof thermal stress. The changes to cardiovascular response require the coach to do some maths andrecalibrate the appropriate values for their athletes to achieve when they work in water. I learned fromexperience that it is not a good idea to try to get an athletes heart rate up to levels comparable withthose y ou would expect them to achieve during an aerobic workout on dry land. Its not that they arejust being lazy ! There are equations that can supposedly predict maximum heart rates for water-baseddrills, but I prefer to get the athlete to use a heart rate monitor and gauge their HR response against theusual tests (observation, RPE etc) or against values recorded in a water-based maximal training sessionthat y ou have prev iously conducted. Either method should allow the coach to set training zonesequivalent to those used on dry land. Although I have found no research on anaerobic work in the pool,I do use it for anaerobic conditioning sessions. I apply the same training principles as on dry land(adapted as appropriate for water work), namely :

- high-intensity efforts with recovery efforts in between ; - 20 to 30min session

duration

I favour the flexed running position (see below) because it allows the athlete to switch into a highercadence and thereby kick into the high-intensity work phase in the least amount of time.

Muscular sy stem The muscle actions that we so carefully deconstruct and use as the basis of ourstrength and conditioning programmes with athletes on dry land change dramatically in water, as this isa v irtually grav ity -free environment. The key conceptual difference is that the normal prime-moverdeceleration action (eccentric contraction or lengthening against resistance) does not alway s apply inthe water. Depending on the movement and the training equipment being used, some muscle actionsbelow the water surface are concentric only . This in turn means that the antagonist muscle takes on theprime mover role for the eccentric or return phase of an action, but moving concentrically . Using abicep curl as an example, on land with weights (dumbbells), grav ity acts on the weight and the bicepswork eccentrically (lowering phase) and concentrically (lifting phase) during the curl. If y ou performthe same exercise in the water just wearing webbed gloves, force is generated against the direction ofy our motion, so the biceps contract concentrically in one direction (up or flexing) and the tricepscontract concentrically in the other (down or extending). If y ou now perform the same exercisewithout the webbed gloves but using dumbbells made from foam to prov ide buoy ancy , y ou have towork against the effects of buoy ancy and the triceps will be working eccentrically and concentricallyduring the bicep curl. This all gets very complicated, particularly if y ou are undertaking strength workin shallow water (where there is some grav itational effect on the body ). There is very scant researchwork on this area to help us, either. The best we can say here is that, as the example of the bicep curlshows, therapists should not assume that a specific muscle strengthening exercise on dry land can bereproduced in the water in order to achieve the same rehab goal.

Nervous sy stem Research shows we have a higher pain threshold when immersed in water, andpatients with lower-limb arthritis show significant improvements in proprioception and balance withwater-based training(10). It is reasonable to suggest that athletes recovering from joint injuries such asACL rupture might enjoy similar improvements in proprioception in the water.

Is swim m ing a good workout? Swimming is undoubtedly a great way of training the cardiovascularand musculoskeletal sy stems, but I will alway s prefer aqua training over a swim session for my clients,for two main reasons. First, most land-based athletes are not trained swimmers. If y ou are a strongswimmer with great technique, then swimming may be a good cross-training modality , but I have foundthat I can train my athletes quickly and effectively in the aqua running techniques described below to alevel that produces a really valuable training effect. I know that it would take far longer to get them to agood enough standard of swimming to obtain similar results, and time is a precious commodity insports rehab and conditioning. Second, most of my clients are involved in running-based activ ities, soswimming offers less transferable benefits than drills that replicate the movement patterns of their land-based activ ities.

How to plan effective workouts - Cardiovascular training

Deep water running is a good alternative to pounding the streets day after day (5,6). In a joint study ,researchers from England and Tasmania compared the effectiveness of deep water running and roadrunning in improving maximum oxy gen uptake in a group of 20 untrained y oung women. Both trainingprogrammes produced similar and substantial improvements in VO2max, and the researchers



concluded that deep water running, in common with other aerobic activ ities, offers significantcardiovascular benefits when performed at an appropriate frequency (three to five day s a week),intensity (60% to 7 5% of maximum heart rate) and duration (20 to 60 minutes)(11).

Aqua jogging/running The two terms tend to be used interchangeably . Although I believe the twoadapted techniques outlined below give more bangs for y our buck, standard aqua jogging is a goodtraining technique, so here are the basic rules on form: l Maintain almost upright body position, withjust a slight forward lean from the pelv is (5 to 10 degrees) l Keep trunk tight l Bring the knees toapproximately 90 degrees and simply push the foot straight down behind y ou (avoid a bicy clingmovement) l Pull the arms forward and back with no lateral movement, keeping the hands relaxed andrelaxed thumbs pointing up (see Figure 1 , over).

I frequently hear coaches and athletes argue that standard aqua jogging is too easy to prov ide anadequate workout. It is true that this kind of running in deep water doesnt really create a lot ofdisruption to the flow. So I adapt it, using techniques shown to me by Marques Church, to increase thelevel of challenge for the athletes I work with, and they happily accept that these sessions are as toughas any thing they undertake on dry land. It is well worthwhile try ing these out y ourself to get a sense ofthe effort required. Y ou can progress or alter the intensity of these drills by employ ing any of thefollowing techniques: l using fins on feet l using a 2:1 ratio of feet to hands (two leg drives to each armdrive) or v ice versa l attaching floats to arms or legs (watch for excessive build up of lactate) l usingbungees attached to the side of the pool to add variety or as a tool for interval work (go to full extensionand hold/go to full extension then drift and repeat/go to extension, drift back to edge of pool and go outagain).

Drill 1: Flexed position running A whole-body exercise similar to running. Unlike standard aquajogging, when performing this drill the body will be almost horizontal. This technique is particularlyuseful for games play ers (hockey , rugby etc) who adopt a flexed position. Y ou will get increasedactivation around the gluteals, hip flexors and hamstrings.

T echnique l Work in deep water where y our feet cannot touch the ground l Once in the water, lowery our hips so y ou maintain a forward lean from the pelv is of about 45 degrees l Keep trunk tight l Reachstraight forwards to full extension with one arm, then pull y our arm back with palm leading. Bend y ourarm as y ou pull back, until approx 90 degrees at elbow, then continue pulling through to y our hip lBring opposite knee forward towards y our chest (keep toes pulled up so foot is flexed) while pushing theother leg straight back until fully extended. Keep toes/foot flexed until the bottom of the leg drive,when the foot may plantar-flex l Maintain hip, knee and ankle alignment (avoid using a breast-strokeleg movement, especially when fatigue starts to set in).

Drill 2: Upright running This form of aqua running (see Figure 2, right) is predominantly used forrecovery specific to upright running musculature, cadence development and maximal resistance work.It also helps improve flexibility and range of movement, which has particular benefits for slow runnerswho shuffle along with a short stride length. Weve also found that our horizontal jumpers returningfrom injury like this technique because the large range of movement helps to stop them from tighteningup during their rehabilitation.

T echniquel Maintain almost upright body position, with just a slight forward lean from the pelv is (5 to10 degrees) l Keep trunk tight l Reach straight forward to full extension with one arm. Pull arm backwith palm leading (scoop action), until the elbow bends to approx 90 degrees. Continue to pull throughto y our hip l Bring opposite knee forward towards y our chest (keep foot flexed), extend the legforwards. Once fully extended in front of the body , pull leg straight back through the water, aiming tokeep the leg as straight as possible. Push toes out (plantar-flex) at the bottom of the leg drive l Maintainhip, knee and ankle alignment.

Drill 3: Cross-country ski running In this drill the legs remain straight throughout and the majormovement comes from the pelv is, rather than the knee, which creates much greater glutealcontraction. This is a great drill for warming up and prov ides increased gluteal function and pelv iccontrol. Good for lower limb recovery .

T echnique l Maintain almost upright body position, with just a slight forward lean from the pelv is (5to 10 degrees l Keep trunk tight l Adopt an opposition position, extending y our right arm and left legforward at the same time l Keeping both arms and legs straight, begin to scissor walk l Y ou should aimto swing y our arms and legs an equal distance in front and behind the line of y our body l Keep handsrelaxed with relaxed thumbs pointing up. If y ou want to increase the intensity y ou can turn y our handsto form a paddle, flex each foot as it drives forwards, and point it pushing back.

For anaerobic cardiovascular training, see Table 2 (below), which gives an illustrative session that I runwith participants using a flexed running position. Strength and power training Pool-based ply ometricscan be excellent for strength and power development. While Ive had some interesting conversations(arguments) with coaches who dont believe y ou can develop power in the pool, my own experiencesuggests otherwise and there is even some research to back me up. In 2001 researchers found that itwas possible to make improvements in vertical jump performance by using a pool-based ply ometricsprogramme and that there were no significant differences between land and water-based trainingmethods(10). More recently , in 2005, US researchers showed that pool-based ply ometrics can producesignificant increases in vertical jump scores and prov ide similar benefits to land-based ply ometrics(12). This is great news for any one looking for a low-risk power-based training tool. Ive also used thisvery successfully with athletes returning from injury . Research has shown that on dry land themusculoskeletal sy stem is subjected to minimum impact forces of three to five times body weight whenlanding during ply ometric drills such as depth jumps. For this reason, most high-intensity land-basedply ometric drills are out of bounds for athletes returning to fitness. But ply ometric training in waterallows them to slot back into the training programme early . A 7 0kg male performing a ply o drill in apool will reduce the impact forces from a range of 210kg to 350kg to a range of 35kg to 57 kg. Not bad if



y our knees are a bit on the dodgy side! The Ohio-based team found that many healthcare professionalsnow use the pool for injury rehab, and several publications expound the v irtues of pool-basedply ometrics(10). Y ou can change the intensity level simply by changing the level of the water. Thewater prov ides support as the athletes body moves downwards, and resistance as the athlete explodesupwards. The water will also add resistance to lateral movements, with the potential benefit ofimproved strength (a massive bonus for athletes attempting to get back to full fitness after an enforcedinjury lay off). As water-based strength and power training is still very underdeveloped, there seem tobe no hard and fast rules. The Ohio University team suggests y ou adopt the same training principles ason dry land (volume, intensity , frequency ). Table 3 is an illustration of sessions I have used withathletes, including netball play ers with chronic knee injuries preparing for international competition.The play ers were able to maintain strength and power without the need for land-based ply ometrictraining sessions.

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