By Jodie Humphrey
Jodie Humphrey, ATC, PT, CSCS, is a California-based freelance writer. She has worked as an athletic trainer at Dartmouth College, the University of Massachusetts, and Northeastern University.
Training & Conditioning, 12.4, May/June 2002, http://www.momentummedia.com/articles/tc/tc1204/trauma.htm
The body’s response to injury involves a coordination of tissues, organs, and systems in a complex choreography that could draw the envy of a Broadway director.
Initially, local disruption of homeostasis sets the stage. Then, the muscles, nerves, and sensory organs of the skin increase their communication with the brain. In response, the brain refocuses cellular activity to the injured site. The muscle fibers are then instructed to shorten the actin-myosin filaments to splint, or “guard” the involved joint, damaged muscle, or inert tissue. This muscle guarding causes protein synthesis to escalate in order to meet the increased metabolic demand. The level of ionic calcium is significantly increased to meet myosin’s ATPase activity. More energy and basic nutrients are required for protein synthesis, cellular regeneration, and clean-up of excess fluid. As the final scene of this injury production, pain is experienced to signal tissue destruction.
These interrelated biological processes are what athletic trainers and physicians strive to conquer with modalities, medication, immobilization or mobilization, athlete education, and other rehabilitative interventions. Yet many of those who work with injured athletes focus their treatments on only one type of tissue, such as a ligament for an ankle sprain. Given the number of tissues that are potentially involved in an injury—and the body’s coordinated response—it makes sense to assess and treat an injury based on all of the involved tissues.
This article discusses how to approach an injury from a multi-tissue, multi-system perspective. Since it is impossible to discuss all potential injuries to an athlete, this article reviews two common sports injuries—ankle sprain and hamstring strain—and discusses the tissues involved and treatment options.
In an ankle sprain, the primary type of involved tissue is the ligament and the mode of injury is a stretch, compression, or twisting of tissues in and around the ankle. In a typical ankle sprain, the elastin in the ligaments is compressed, stretched, or sheared beyond its capacity (elastin is an extensible protein that gives the ligament its integrity by being able to react quickly to high velocity and unpredictable movements in agility activities).
Since many types of tissue surround the ankle joint, there are a number of secondary tissues that should be considered in any diagnosis and treatment. These secondary tissues include: joint capsule, bone articular surfaces, articular cartilage, joint proprioceptors, muscles, tendons, retrocalcaneal bursae, retinacula, deep peroneal nerve, and capillaries stemming from the peroneal artery. For example, if a ligament tears in an ankle, there can be some corresponding vascular damage, joint capsule sprain, articular surface impact, joint receptor damage, and muscle strain as the involved tissues attempt to decelerate the gapping joint.
To determine the severity of surrounding tissue involvement, the degree of tissue damage can be evaluated as soon as the acute symptoms resolve. Some effective assessment tools for identifying tissue involvement in an ankle sprain include:
1. Laxity relative to the non-involved side (for ligament and joint capsule integrity).
2. Figure-eight measure for edema (location of capsular bulge can signify injury location of inner tissues such as the retinaculum joint capsule).
3. Pain-free joint range of motion.
4. Tenderness to palpation.
5. Athlete’s percent of function compared with the uninvolved limb.
6. Strength and endurance.
7. Pain scale at rest, with activity, and after activity.
In addition, some popular tools for assessing functional mobility include gait pattern; Romberg test for static balance; squat percentage; step management; lateral movement; multi-directional agility; hop test for power and control; timed hop in place for accuracy and quality of hop, jump, and agility.
Once the degree of tissue involvement and functional mobility is assessed, the next step is choosing the proper modality and manual therapy for treating the ankle injury. When making this choice it is important to consider whether the injury is acute, subacute or chronic. If the ankle injury is acute, utilize rest, ice, compression, and elevation. Grade 1-2 joint mobilization can be helpful for swelling. Also, brace or tape the injured ankle as necessary.
For subacute ankle sprains, use cross-friction mobilization, biofeedback for muscle activation of dynamic stabilizers, and ice baths as needed for inflammation.
Chronic ankle sprains should be treated with electrical stimulation for swelling (muscle pump), electrical stimulation for muscle re-education, and scar mobilization massage techniques. Furthermore, in any phase of this injury, mobilization to surrounding muscle bellies can reduce tension caused from improper gait patterns.
Therapeutic exercise for treating ankle sprains should include dynamic stabilization, proprioceptive neuromuscular facilitation (PNF) using functional movement patterns, plus muscular power and endurance exercises. Power and endurance exercises are in a weight-bearing mode and should only be initiated when full weight bearing is tolerable for the injured athlete. In addition, it is important to consider the remodeling phase to achieve tissue maturity, which takes place during the three to 12 months following injury or surgery. Ideally, therapeutic exercise should be continued throughout this remodeling phase.
For dynamic stabilization exercises, consider the mechanism of injury and suspected injured joint receptors. Be sure the athlete is not excessively compensating for the injured ankle by relying on the hip and knee to maintain balance. To train the injured athlete to move without overcompensating, utilize exercises such as the clock-tape touch, lateral stepping, figure-eight walking, and unilateral balance activities.
When using PNF exercises to treat ankle sprains, diagonal movement patterns that concentrically and eccentrically work on the timing of neuromuscular activity provide stimulation and correction of inappropriate muscular activity. For example, manual resistance concentrically and eccentrically to the combined motion of dorsiflexion, eversion, and forefoot pronation is an effective PNF exercise. Another effective approach is using alternating isometrics to challenge the ankle stabilizers in multiple directions with varying force.
The injured joint may need external stabilization from tape or a brace. Also, damage to sensory organs such as the Pacinian corpuscles is dependent on the speed and magnitude of the injury, and therefore may dictate the proprioceptive and kinesthetic training you employ.
Muscular power and sport-specific endurance exercises should be introduced to the rehabilitative effort once the athlete has subjectively reported greater than 70 percent recovery. That recovery can be measured simply by asking the athlete what percent of activity has been restored since the injury. In addition, functional tests that compare the function of the involved versus the uninvolved limb can provide insight into the athlete’s recovery.
Once the athlete has recovered to 70 percent of pre-injury function, use exercises such as hopping, jump ups, jogging, and lateral bounds to improve neuromuscular endurance and power. While performing these exercises, the athlete must show no symptoms. If the athlete experiences pain or other symptoms of the injury during these exercises, modify the intensity, repetitions and frequency until tolerance to these exercises is improved.
In a hamstring strain, the primary type of involved tissue is muscle. Secondary tissues that could be involved include the surrounding fascia, the sciatic nerve, hip musculature and tendons, plus sensory organs. The mode of injury in hamstring strains varies from a quick stretch to prolonged force production or repetitive overuse, twisting, or sudden and intense acceleration or deceleration.
At the time of injury, the hamstring muscle myofibrils are stretched beyond functional range and force production exceeds actin-myosin capability. In addition, when the hamstring muscle fibers tear, there is corresponding vascular damage to capillaries from the femoral artery, fascia damage, sensorimotor disruption in tissues such as tendon and muscle, and neuromuscular timing dysfunction that is necessary to restore the natural dynamics needed in sports.
Recovery from hamstring strain depends on the amount of injured muscle fibers, the extent of motor end-plate damage, and any axon damage. Any damage to nerve tissue becomes a hindrance to rehabilitation because nerves regenerate very slowly, some say millimeters per day, depending on where the nerve was injured. Typically, it takes three to 12 months for nerves and other soft tissue to complete the remodeling phase. Moreover, without adequate rehabilitation of nerve activity (to decelerate and accelerate the desired agility and speed movements), the muscle is prone to re-injury.
As in other injuries, the degree of tissue damage needs to be assessed. Some useful tests for assessing tissue involvement in a hamstring strain include:
1. Checking tenderness to palpation and defect, and active range of motion against gravity.
2. Measuring tissue temperature to identify metabolically active portions of the injured muscle and tendons.
3. Measuring girth for swelling.
4. Manual muscle testing for concentric force, eccentric force, and repetitive trial endurance.
5. Assessing passive, pain-free flexibility.
6. Hands-on, multi-directional soft-tissue mobility testing to assess the fascia, muscles, and tendons.
Tests for functional mobility assessment include: observing the gait pattern, especially for limited swing of the involved leg; squat percentage; step management; lateral movement; multi-directional agility; hop test for power and control; timed hop in place for accuracy and quality of hop, jump, and agility; and jog-speed tolerance.
Manual therapy and modality choices, as with ligamentous damage, depends on whether the injury is acute, subacute, or chronic. For acute hamstring strain, treatment should utilize ice, interferential electrical stimulation, and edema massage. In cases of subacute hamstring strain, try using cross-friction mobilization, biofeedback for muscle activation of dynamic stabilizers, and ice as needed for inflammation.
Chronic hamstring strain can be treated with electrical stimulation therapy for pain and muscle re-education, plus deep-tissue mobilization to restore the affected tissues to their pre-injury levels. Be careful with deep palpation near the sciatic notch where the sciatic nerve exits to the superficial level.
Therapeutic exercises for treating hamstring strain should include strength training, muscular power and endurance training, dynamic stabilization and co-activation, and PNF for neuromuscular rehabilitation.
Strength training during rehabilitation is designed to restore local muscle endurance and hypertrophy. Initially, isometrics have been found to be effective therapeutic exercises when the rehabilitating athlete performs multiple sets of maximal to near-maximal muscle contractions done for three to 10 seconds daily at 20-degree increments of knee flexion. Eccentric isotonic exercise is necessary to maximize the muscle’s restoration of force production, since eccentric work has the greatest force capacity in muscle. Concentric loading needs to be progressed with caution in order to avoid injuring the healing scar that is forming at the torn muscle ends.
In order to achieve local muscle endurance, athletes need to train in the nine- to 12-repetition range. Have them perform three to five sets with light to moderate weights, and make sure that they take brief rest periods with a 1:1 work-to-rest ratio between sets. In order to achieve hypertrophy, repetitions should be three to five with maximal weight, with a work-to-rest ratio of 1:3.
Muscular power and endurance exercises such as hops, jump ups, jogging, and lateral bounds should be employed once the athlete has subjectively reported greater than 70 percent recovery of the involved tissue to pre-injury function. The athlete must be able to perform these activities without symptoms during and, more importantly, hours after the treatment sessions. If stiffness or pain sets in hours after the treatment, that is a sign that the treatment is too intense and that it needs to be modified.
Dynamic stabilization and co-activation exercises are used to restore the balance of muscle agonist/antagonist and facilitator muscles by challenging the lower extremity’s dynamic stability and agility. Hop tests have been shown to be clinically sensitive and reliable to assess functional control. These tests include the single hop, triple hop, four hop, timed hop, and cross-over hop. Exercise for dynamic stability and agonist/antagonist coactivation needs to be performed on various platforms and surfaces to increase proprioceptive and kinesthetic demands. If needed, the athletic challenge can be increased by adding an external load placed on the non weight-bearing limb.
When employing PNF exercises for neuromuscular system rehabilitation, remember that manual contact allows greater feedback for substitutions in muscle activation that cannot be assessed in closed-kinetic-chain activities. Diagonal movement patterns that concentrically and eccentrically work on timing of neuromuscular activity provides stimulation and correction of inappropriate muscular activity. For example, alternating isometrics of the quadriceps and hamstrings at various levels of knee range is one effective employment of PNF exercises for hamstring strains.
The concept of assessing and treating injuries by taking all of the involved tissues into consideration addresses the reality that no tissue injury occurs in isolation. In any given injury, all of the involved tissues will have an impact on the athlete’s rehabilitation and on the chances for full recovery.
By involving all of those involved tissues in your treatment plans, you will not only boost the efficiency of your rehabilitation efforts, you will also enhance the athlete’s chances for full recovery.
Articles that have appeared in previous issues of Training & Conditioning are archived at www.AthleticSearch.com.