Kyle carefully walked to the edge of the pool. Scars from his three annterior cruciate ligament (ACL) knee surgeries were visible on his legs. Within moments, the Nevada Wolfpack placekicker was running on an underwater treadmill using his arms to fight the jet-propelled turbulence. Kyle is able to run vigorously without the impact forces experienced on land. By adjusting the water depth, a gradual progression of resistance is applied for a safe and comfortable return to land-based activity. Specific drills in the water can be related to sports play and are practiced with less stress using the water's natural resistance. Kyle is monitored during his first weeks after ACL surgery in the pool by an athletic trainer, a physical therapist, and a physician. This health care team will monitor undue stress while challenging the muscles and balance at the surgical knee (15).
Knee injuries can occur with sports activities such as cutting, jumping, and quick changes of direction. Water training may provide an effective gateway for healing and return to play on land. As a member of the postrehabilitation team, health and fitness professionals may be positioned to offer a water-based program to athletes or weekend warriors with sports-specific knee injuries. In this column, Daryl Lawson, PT, D.Sc., and I will examine water's role in ACL knee injury recovery and offer some in-water training strategies.
H2O SOLUTIONS FOR RECOVERY
The properties of buoyancy and resistance provide a unique training environment that enhances comfort and promotes a balanced approach to improving range of motion (ROM) and cardiovascular, muscular, and functional conditioning. The following is a snapshot of studies that provide information for designing an ACL knee recovery program:
Walking in water immersed to the xiphoid process reduces weight bearing between 71% and 80% compared with dry land (12). Clients with a need to decrease weight bearing at the lower extremity, secondary to pain or weakness, could benefit from working out in the water.
Brindle et al. (5) suggested that after wound healing, an aquatic environment may be ideal during all phases of ACL rehabilitation postsurgery, especially given the concerns about providing an ideal weight-bearing load. By varying the depth of the water and using flotation and resistive devices, patients can safely progress through knee ROM and neuromuscular recovery activities. The training program also can incorporate a sports-specific functional movement pattern (e.g., hopping and jumping). Therefore, the reduced weight-bearing environment of water also can provide a safe environment for your client's long-term training when aggressive ROM, strengthening, and sports-specific activities on dry-land activity are not recommended.
Return to Play
By using water as a surrounding liquid resistance medium, overload to the muscles can be applied through normal patterns of play or by using functional activities of daily living that can lead to improvements in neuromuscular adaptations (9,21).
Roi et al. (22) reported that a 35-year-old world-class soccer player who sustained a complete tear of his ACL during the competitive season was able to return to play within 90 days of surgery. Starting 8 days after surgery, he completed two rehabilitation sessions per day, 5 days per week, plus one session on Saturday. Sessions included a combination of aquatic therapy and land-based flexibility, strength, and field work. The water- and land-based progressive rehabilitation program allowed the patient to play for 20 minutes during a game and a full game 77 days after surgery. No follow-up treatment was needed after 3 months. This case report indicates that personalized progression of water- and land-based training is consistent with an optimal and early return to play.
Function and ROM
Twenty patients with intra-articular ACL reconstructions were randomly assigned to a land or water exercise group. Thigh girth, joint effusion, and knee passive ROM were recorded at 2-week intervals for the first 8 weeks postoperatively. Results indicated greater gain in peak torque during land exercises, however, the water exercise group noted greater minimization of joint effusion and greater self-reports of functional improvements (23).
Napoletan et al. (17) looked at the difference of water treadmill versus conventional land treadmill and cycling training in people who underwent ACL reconstruction. Their study found greater muscle girth at the calf and thigh, greater quadriceps strength, and better ROM at the knee for those doing the water treadmill workout.
Clinical results show that athletes who participate in water rehabilitation and land-based postrehabilitation have better scores on postural sway, indicating better balance. They also experienced fewer episodes of reinjury after return to play (9).
SHALLOW-WATER CARDIO AND MUSCULAR RESPONSES
Masumoto et al. (12-16) measured electromyography (EMG) responses of participants walking on an underwater treadmill. The study found that when ambulating with water at the depth measured at the xiphoid process, the body is unloaded about 80% compared with when on land. Results from their studies provide valuable insights for program design.
When the exercise intensity was matched to cardiorespiratory and rate of perceived exertion (RPE) responses, muscle activity was approximately 70% lower during both forward and backward walking in water compared with land walking in young and older participants. Despite the lower muscular activation, cardiovascular intensity was similar between land and water exercises. It is thought that in water, the arms moving through the water' resistance may contribute to higher cardiovascular overload (12,16).
A few studies have looked at the differences of walking forward and backward in water. Compared with walking forward, walking backward against currents is reported to result in higher cardiorespiratory responses while reducing joint compressive forces on the lower extremity (14,15). Participants with knee conditions should include backward walking to optimize cardiovascular training.
Compared with land walkers, water walkers had lower peak muscle activity than on dry land, however, they had higher average muscle activity for the quadriceps (rectus femoris and vastus lateralis), hamstrings (biceps femoris), and gastrocnemius. Tibialis anterior muscle activity was similar in both lower extremities (12).
Walking backward in water, when compared with walking forward in water, resulted in higher EMG activation of the paraspinal muscles or erector spinae (61%), the quadriceps (83%), and tibialis anterior (47%). Investigators suspect that the higher activation of the paraspinal muscles is caused by using the arms to assist with locomotion, and greater use of the quadriceps is linked to the higher propulsion force required to move through water, especially when done against a current. Walking backward most likely contributed to the greater use of the tibialis anterior (14,15).
Muscular Responses During Gait Training
The EMG measurements of walking on land and in three depths of water were compared to determine differences in muscle pattern use and to identify the extent to which walking in water could effectively improve gait on land (20). Results showed that at the shallowest depth (up to 50% of body height), water walking engaged the same muscular patterns and duration of muscular activity compared with land. At deeper depths (up to 75% of body height; chest deep and deeper), muscle activation was very different compared with walking on land. Consequently, these deep-water activities did not mimic land movement and would be ineffective in providing neuromuscular reeducation for walking on land. The investigator concluded that reeducation for gait training should be performed only in water less than 50% of body height to optimize crossover to land (20).
DEEP-WATER MUSCULAR RESPONSES
Kanada et al. (7) examined muscle activation during land walking and deep-water running performed at three self-selected speeds (slow, moderate, and fast paces). They discovered that deep-water runners had lower muscle activation for the soleus and medial gastrocnemius and higher activation of the quadriceps (rectus femoris) and hamstrings when compared with land walkers when matched for speed. This occurred at all three paces. Investigators concluded that deep-water running could provide effective general conditioning for the quadriceps and hamstrings.
IMPLEMENTING A WATER EXERCISE PROGRAM FOR YOUR ACL CLIENT
Clients must obtain medical clearance before starting an exercise program. In addition, you may need to contact the orthopedic physical therapists to ensure that the exercises are appropriate during postrehabilitation conditioning. It is very reassuring for your client to have a continuum of care from the physical therapist to you to optimize his or her outcome (8).
The following are a number of items to address with clients before exercise participation. During the program, trainers should check for abnormal responses to exercise and return to these screening components to frequently check for readiness to continue the training.
ACL: Participation Screening Checklist and Guidelines
Before exercising in water, clients should be 12 to 16 weeks postsurgery (depending on wound healing and physicians' and physical therapists' recommendations).
- Full pain-free ROM compared with the other knee. Have client sit in a chair to perform knee extension with the good leg and then repeat with the affected limb. Check the ROM for both sides.
- A visual analogue scale (VAS), with 0 being no pain and 10 being intense pain, is a useful tool to evaluate pain (6). Ask your client to rate pain on the VAS from 0 to 10. If pain increases 2 to 3 points, it would be best to decrease intensity and duration of the exercise program until the pain rating decreases. If it does not decrease, then refer the client back to the physician or physical therapist for an evaluation.
- Swelling, edema, or effusion of the knee can occur after exercise. Overuse of a knee that has not been routinely engaged in exercise can and will display edema. The edema can be managed by ice and elevation, and the edema should decrease during the next few days (4). Occasionally, pain and soreness will accompany the edema, but they also should decrease during the next few days (continue to use the VAS to track pain). It is very important that the trainer be aware of the signs and symptoms of edema that are not normal; the client would need to seek medical attention immediately. Knee joint infection is a rare but potentially devastating complication of ACL reconstruction (2). Signs and symptoms would be swelling leading to pain and redness. There's usually no trauma before the onset of pain. Septic arthritis often occurs with a fever.
- Edema that will not resolve with rest, ice, and elevation may be an indication of some intra-articular or ligamentous problem (reinjured ACL, medial collateral ligament, lateral collateral ligament, posterior collateral ligament), and your client should seek follow-up diagnostic testing to rule out a problem that could become worse with postrehabilitation. With intra-articular or ligamentous problems, your clients may have immediate pain that worsens when they try to walk or bend their knees, experience a popping sound at the knee, are unable to bear weight on the injured knee, or have a feeling that the knee might buckle or give way (Madiagan Army Medical Center Practice Guidelines).
- Obtain medical clearance and check for cardiovascular risk factors using the guidelines suggested by the American College of Sports Medicine (1).
ACL: Training Objectives
- Stretch the tensor fascia latae, quadriceps, gastocnemius, hamstrings, gluteals, and soleus.
- Strengthen all muscle groups of the knee, hip, leg, trunk, and general upper extremities. Surface area (paddle) and buoyancy equipment (foam dumbbells) can be used to increase water's natural resistance for muscular overload. Equipment broadens the progression and extends the time an athlete can be challenged in the pool. Adjustable resistive devices attached to the leg seem to be safe and effective for knee extension exercise by clients after ACL surgery. Biscarini and Cerulli (3) found that underwater knee extension exercises performed with light resistance resulted in no ACL stress (with no shear joint forces) over the entire ROM.
- General cardio conditioning.
- For ACL clients, 6 to 10 weeks postsurgery is the weakest point in the reconstructed ACL ligament, and the most strain is measured from about 15 to 30 degrees ROM (19). Trainers need to understand what type of ACL repair someone had (patellar, hamstring, or cadaver) and find out from the physician or physical therapist when patients can begin aggressive exercises involving the knee, with a full ROM. It is important for personal trainers to have this information to optimize their client's outcome.
- Functional exercises are suggested to decrease knee stress (co-contraction of the quadriceps and hamstring decreases the anterior translation of the tibia; hamstring strengthening promotes knee stability).
- Knee brace can be worn in the pool for exercise (especially if cutting, jumping, pivoting, and stepping down are included).
- Avoid breast stroke, rotary-type kicks with quick snapping movement, quick stopping, ballistic knee movements such as jumping or rebounding in very shallow water, or high-speed push off the pool wall.
- Minimize quick changes in direction for 6 to 8 months and minimize complicated choreography.
- Include balance, coordination, and proprioception training that mimic sports plays.
- Gradually increase the size and/or speed of movement to adjust resistance overload. Add adjustable resistive equipment for progression when appropriate.
- Change water depth for comfort to adjust impact and lower-body load. Progress walking to shallow water depth (50% of body height or shallower) to optimize gait crossover training to land.
- Follow the stretching guidelines of the health care provider and work to end of ROM during warm-water static stretches only.
- Use gradual progressions for squats and step work, beginning with mini squats in water that off-loads the body comfortably and progressing to shallower water gradually.
- Include walking forward and backward against an adjustable rate of current flow, if possible, for general muscular and cardio conditioning.
SUGGESTED SHALLOW-WATER PROGRESSIONS
Sculling, preferably with webbed gloves at the surface, offers balance support and helps stabilize the body during exercise (19). Encourage clients to adjust intensity according to their own RPE and readiness for activity. Our sample program is performed in a Hydroworx pool that provides adjustable depth, turbulence flow speeds, and bottom treadmill speeds. Without a fitness pool, choose a depth to achieve an appropriate impact and travel across the pool at various speeds to create variable flow resistance against the body. Engage athletes with timed distance drills to challenge them and to track improvements.
Objectives: Strengthen lower body and challenge balance
Begin with static mini squats and gradually increase the duration and the depth of the squat until clients can perform single-leg, dynamic, repetitive, or more complex squat combinations. Progressively decrease water depth and/or squat on the step.
Exercise 1: Squat in shallow water using hands in water for balance.
Exercise 2: Squat with hands overhead to decrease buoyancy of body and challenge balance further.
Exercise 3: Single-leg squat on step. Move the leg around the body like the hands of a clock with each squat to challenge balance.
Exercise 4: Resisted squat and lat pulls. Squat using surface area resistive devices for training that integrates strengthening for the lower and upper body while challenging balance.
Walking to Running Progression
Objectives: Cardiovascular endurance, lower- and upper-body muscular endurance, balance
Begin the progression by slowly walking forward. Progress to a jog and more complex movements such as grapevine sideways and walk/jog while periodically stopping to balance on one leg (freeze frame). Add walking/jogging backward. Then add equipment for combination upper-body work or tethered walking/jogging/running for balance challenge.
Exercise 5: Walking or jogging forward. Progress to grapevine on treadmill (or traveling) using gloves for balance and assistance.
Exercise 6: Walk backward against turbulence (or traveling) and perform flies (scapular adduction) with gloves webbed open or with surface area resistive devices for upper-body work.
Exercise 7: Tethered running for dynamic balance. Tether is pulled side to side to challenge balance during running against turbulence or traveling in the pool.
Objectives: Cardiovascular endurance and lower-body strengthening. Some core work
Begin seated on a kickboard, floating your legs off the bottom, and flutter kick using straight legs, progress to knee extension/flexion, and add equipment for overload. Change the body alignment to prone and push and pull with arms and legs (crawl forward) to increase intensity and core challenge. Add turbulence and a tether to increase core challenge and a buoyancy belt for support.
Exercise 8: Suspended seated bilateral kicking (flutter straight legged, progressed to knee flexion and extension).
Exercise 9: Perform "rock climbers" by crawling with feet off the bottom. Add surface area overload when appropriate.
Exercise 10: Progress to running. Kyle is running intervals in a tank that provides adjustable flow turbulence, treadmill speed, and water depth to regulate impact as needed.
Stepping to Jumping Progression
Objectives: Cardiovascular endurance, lower-body strengthening, and balance
Begin with step lunge and recover to a stand, progress to step climb, then step jumps on and then over the top of the step, moving laterally. Add a tether (pulling on the body) for balance challenge.
Exercise 11: Step lunge and recover to standing.
Exercise 12: Jump on top and freeze frame on one leg to challenge balance.
Exercise 13: Ski jump laterally over the step, landing beside the step on the pool bottom.
Exercise 14: Perform tethered jumps that progress to run and jumps with lateral tether pulls for balance and agility challenges.
Objective: Flexibility for hamstring and quadriceps
Use a buoyancy device such as a kickboard or one that attaches to the leg or step support to enhance stretches. Increase ROM gradually and work in warm water for safe and comfortable flexibility exercises.
Exercise 15: Kickboard-assisted hamstring stretch. Progress from short lever (under thigh) to longer lever (under ankle).
Exercise 16: Perform single-leg squats to target the quadriceps using the step or buoyancy device on the leg to assist ROM.
Extra Shot: Marc Paul and Kyle work as a team with computer-assisted underwater views from the side and front that provide for biomechanical feedback and analysis.
ABNORMAL RESPONSE TO EXERCISE
- Moderate increase in pain and symptoms (refer to section on screening guidelines and reevaluate for readiness to continue exercise) (16).
- Moderate or greater pain during or after exercise
- Loss of ROM
- Loss of function. Increase in difficulty with land activities such as stair climbing, moving from a sitting to standing position, and squats.
- Increase in local temperature at the knee.
RESPONDING TO ABNORMAL RESPONSE
- Ice and rest (refer to screening for more details) (16).
- Adjust water depth (deeper) to decrease weight bearing or work in deep water only
- Perform lower-extremity exercises in straight planes
- Simplify exercises
- Reduce size and/or speed of movement
- Avoid end of range. Watch that water currents do not push the limb past the end of range of knee motion (hyperextension or hyperflexion of the knee)
- May have to eliminate eccentric knee extension activities such as squats, rebounding (jumping), and step work
WHEN TO REFER TO A PHYSICIAN, PHYSICAL THERAPIST, OR HEALTH CARE PROVIDER
- Persistent increase in pain and swelling (refer to screening section for more guidelines) (16)
- Loss of movement because of pain
- Development of a limp
EVALUATION FOR BRIDGING TO LAND-BASED TRAINING
Observing signs and symptoms of pain and swelling will provide information about the appropriateness of the intensity, frequency, and duration when an athlete moves from the water to the land. Each athlete may be different depending on the intervention performed on the knee. Therefore, it is important to have good communication skills and check for swelling as he or she is progressed to land.
EXPLORING NEW ENVIRONMENTS AND PARTNERSHIPS
Personal trainers are encouraged to work within their scope of best practice as part of the health care team. With knowledge and experience, trainers can offer individualized exercises to extend training after clients "graduate" from rehabilitation. Water exercise leadership skills offer options that enhance a trainer's expertise as a member of the rehabilitative team. By taking your clients from postrehab to normal activities of living, you'll help improve their capacity to move effectively and speed up their return to play.
The authors thank the University of Nevada, Reno, Wolf Pack Athletic Department, and former Head Athletic Trainer Marc Paul, M.S., ATC, for access to the rehabilitation pools; and to our athlete, Kyle Tafelski.
Photography by Ted Cook. Photographs courtesy of the University of Nevada, Reno, and WaterFit.
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