Chapter 13 Prevention Sports Injuries

Muscular Endurance

Ability of muscle tissue to exert repetitive tension over an extended period Fatigue is related to endurance Relationship between strength and endurance Lifting low weights/faster velocity/more repetitions Rate of muscle fatigue is related to the endurance level of the muscle (i.e., the more rapidly the muscle fatigues, the less endurance it has). —As muscle endurance is developed, density in the capillary beds increases, providing a greater blood supply, and thus a greater oxygen supply, to the working muscle —Increases in muscle endurance may influence strength gains; however, strength development has not been shown to increase muscle endurance

Muscular Power

Ability of muscle to produce force in a given time Started when at least 80% of strength Weight training at higher contractile velocities Use of plyometric exercises Explosive exercise that maximizes the stretch reflex Caution: injury potential

Joint Mobilization: Contradictions

Acute inflammation Advanced osteoarthritis Congenital bone deformities Fractures Hypermobility Infections Malignancy Neurological signs Osteoporosis Premature stress on surgical sites Rheumatoid arthritis Vascular disease

Isokinetic Advantages/Disadvantages

Advantages 100% loading throughout ROM Pain disengages mechanism Disadvantages As muscle fatigues, resistance decreases Most machines only permit concentric contraction Cost of the machine, computer, and software package ranges from "$25,000 to $60,000

Dynamic Strength: Advantages/Disadvantages

Advantages Permits exercise of multiple joints simultaneously Allows both eccentric & concentric contractions Permits weight-bearing, CKC exercises Disadvantage When a load is applied, the muscle can only move that load through the ROM with as much force as the muscle provides at its weakest point

Phase 3: Muscular Strength

Although static strength (isometric strengthening) is used during phases 1 and 2 in a pain-free arc of motion, dynamic strengthening is preferred in phase 3 of the program. Dynamic strength Concentric—shortening of muscle fibers decreases the angle of the associated joint Eccentric—muscle resists its own lengthening so that the joint angle increases Concentric and eccentric—also referred to as positive and negative work Eccentric contractions—generate greater force than isometric contractions Isometric contractions—generate greater force than concentric contractions Less tension is required in an eccentric contraction Major disadvantage: delayed-onset muscle soreness (DOMS)

Steps

Assess the patient Interpret the assessment Establish goals

Regaining proprioception

Balance involves positioning the body's center of gravity over a base of support through the integration of information received from the various proprioceptors within the body. Even when the body appears motionless, a constant postural sway is caused by a series of muscle contractions that correct and maintain dynamic equilibrium in an upright position. When balance is disrupted, as in falling forward or stumbling, the response is primarily automatic and reflexive. Injury or illness can interrupt the neuromuscular feedback mechanisms. Restoration of proprioceptive feedback is necessary to promote dynamic joint and functional stability to prevent reinjury.

Progression to Phase 4

Bilateral ROM and flexibility restored Muscular strength, endurance, and power equal or near equal to those of the unaffected limb Cardiovascular endurance and general body strength at or better than the preinjury level Sport-specific functional patterns completed using mild-to-moderate resistance Individual psychologically ready to return to protected activity

Phase 2: Factors that limit joint motion

Bony block Joint adhesions Muscle tightness Tight skin or inelastic dense scar tissue Swelling Pain Fat or other soft tissues that block normal motion

Joint Mobilization: Benefits

Breaking up adhesions and relieving capsular restrictions Distracting impacted tissues Increasing lubrication for normal articular cartilage Reducing pain and muscle tension Restoring full ROM

Phase 1: Controlling Inflammation

Control inflammation Limit hemorrhage, edema, effusion, muscle spasm, pain Reduce length of immobilization (less than 2-3wks) Treat acute symptoms PRICE (protect, restrict activity, ice, compression, elevation) Modality options Cryotherapy, intermittent compression, EMS Electrical therapy TENS (limit pain)

Progression to Phase 2

Control of inflammation with minimal edema, swelling, muscle spasm, and pain ROM, joint flexibility, muscular strength, endurance, and power maintained in general body Cardiovascular fitness maintained at preinjury level

Protection Postinjury

Depends on Injury severity, structures damaged Philosophy of supervising health care provider Restricted activity "Relative rest"- decreasing activity to a level below that required in sport but tolerated by the recently injured tissue or joint Detraining Can occur after only 1 to 2 weeks of inactivity

Phase 3: Focus

Developing muscular strength Endurance Power

Closed kinetic chain (CKC)

Distal segment of the extremity cannot move independently Weight bearing

Open kinetic chain (OKC)

Distal segment of the extremity is free to move without causing motion at another joint Non-weight-bearing

Early phases

Early phases —High-repetition, low-weight exercise may be more productive —Can stimulate blood flow and limit tissue damage

AROM

Enhances circulation Initiation of strength exercises before full AROM Should be relatively painless Full, pain-free, active range of motion is not needed before strength exercises are initiated.

Joint Mechanoreceptors

Four types of nerve endings: Ruffini corpuscles—sensitive to intra-articular pressure and stretching of the joint capsule Golgi receptors—intraligamentous and become active when the ligaments are stressed at the end ranges of joint movement Pacinian corpuscles—sensitive to high-frequency vibration and pressure Free nerve endings—sensitive to mechanical stress and the deformation and loading of soft tissues that constitute the joint —Muscle mechanoreceptors—muscle spindle and GTO

Stretching: Static

GTO override impulses from the muscle spindles Safer, more effective muscle stretch —Movement is slow and deliberate —Stretched to the point where a mild burn is felt; hold for 15 seconds and repeat several times

Interpret the assessment

Identify factors outside normal limits Primary deficits Secondary problems Part of assessment component of SOAP —Decreased range of motion —Muscle weakness or stiffness —Joint contractures, sensory changes —Inability to walk without a limp —Increased pain with activity Identify physical assets to determine the individual's current functional status. Examples: normal gait; bilateral, equal range of motion

Effects of Immobilization: Bone

Immobilization: bone loss as early as 2 weeks after immobilization; as immobilization time ↑, bone resorption ↑ → ↑ brittleness Remobilization: recovery can be several times greater than the period of immobilization; isotonic and isometric exercises during immobilization can some bone loss

Effects of Immobilization: Articular Cartilage

Immobilization: constant contact with opposing bone ends → pressure necrosis & cartilage cell death; noncontact → growth of connective tissue into the joint Remobilization: tissue changes reversible, immobilization <30 days; may not be if >30 days

Effects of Immobilization: Muscle

Immobilization: initially— strength; fatigability, rapid loss; position of immobilization Remobilization: regeneration begins after 3 to 5 days; maximum isometric contraction—4 months Muscle regeneration begins after 6 weeks, fast-twitch and slow-twitch fibers can completely recover; contractile activity rapidly increases protein synthesis; maximum isometric tension may not return to normal until 4 months Electrotherapy (i.e., EMS): aids in reeducating muscles, ↓ pain and spasm; ↓effusion through the pumping action of the contracting muscle; EMS and isometric exercise have not been shown to prevent disuse

Effects of Immobilization: Ligament

Immobilization: weaker, more compliant structure; ↓ tensile strength Remobilization: bone-ligament junction recovers more slowly than midportion of the ligament; recovery depends on the duration of immobilization

Progression to Phase 3

Inflammation and pain under control ROM within 80% of normal Bilateral joint flexibility restored and proprioception regained Cardiovascular endurance and general body strength maintained at preinjury level

Stretching: Proprioceptive Neuromuscular Facilitation

Involves stimulation of the proprioceptors flexibility in one muscle group (i.e., agonist), and simultaneously strength in another group (i.e., antagonist) Techniques Active inhibition Reciprocal inhibition Advantages Early use Single plane or diagonal patterns

Isokinetic Exercise

Isokinetic training also known as accommodating resistance —Allows an individual to provide muscular overload and angular movement to rotate a lever arm at a controlled velocity or fixed speed —Theoretically, isokinetic training should activate the maximum number of motor units, which consistently overloads muscles and achieves maximum tension-developing or force-output capacity at every point in the range of motion, even at the relatively "weaker" joint angles —Examples of equipment: Cybex, Biodex, and Kin Com; coupled with a computer and appropriate software, torque-motion curves, total work, average power, and torque-to-body weight measurements can be instantaneously calculated to provide immediate, objective measurement to the individual and the examiner

Advantages of OKC

Isolate specific muscle group for intense strength and endurance Develop strength in very weak muscles that may not function properly in a CKC system

Dynamic Strength

Isotonic exercise, also known as progressive resistive exercise (PRE) —A maximal muscle contraction generates a force to move a constant load throughout the range of motion at a variable speed —Both concentric and eccentric contractions

Disadvantages of OKC

Limited to one joint in a single plane (uniplanar) Greater potential for joint shear Limited functional application Limited eccentric and proprioceptive retraining

Flexibility: Mechanoreceptors

Muscle spindle Lie parallel with contractile muscle fibers Send sensory info to CNS Muscle length Velocity of length change Excite/facilitate muscle contraction

Joint Mobilization

Oscillating forces applied in open-packed position to "free up" stiff joints

How to Return To Pain-free functional activity

Pain modulation ROM & flexibility Strength Cardiovascular fitness

PROM: Types

Physiological motion: Angular (goniometer) Accessory motion (arthrokinematics)- can't be measured precisely Ex. Involuntary spinning, rolling, or gliding of one articular surface relative to another

Advantages of CKC

Provide greater joint compressive forces Multiple joints are exercised Velocity and torque are more controlled Shear forces are reduced Joint congruity is enhanced Proprioceptors are reeducated Postural and dynamic stabilization mechanics are facilitated Exercises in spiral or diagonal movement patterns

Phase 2: Focus

Restoring ROM and flexibility Maintaining general body strength and cardiovascular endurance

Goal of Therapeutic Exercise

Return injured participant to pain-free functional activity

Kinetic chain

Series of interrelated joints Motion at one joint will produce motion at the other joints in a predictable manner

RROM (resisted range of motion)

Static or dynamic Static Measured with an isometric muscle contraction Used during phases 1 and 2 in pain-free arc of motion Isometric training

Assess the patient

Subjective, or S, portion of the SOAP note —Primary complaint, mechanism of injury, characteristics of the symptoms, functional impairments, previous injuries to the area, and family history Objective, or O, portion —Observation and inspection, palpation, physical examination tests —Establishes a baseline of measurable information -current level of function and dysfunction

Flexibility

Total ROM at a joint that occurs pain free in each of the planes of motion The hip joint may have full passive range of motion, but when doing active hip flexion from a seated position, as in touching one's toes, resistance from tight hamstrings may limit full hip flexion. Combination of normal joint mechanics, mobility of soft tissues, and muscle extensibility

AAROM (Active assisted range of motion)

Working the limb through available pain-free motion with assistance will more quickly restore normal active ROM than working within limited voluntary motion

Stretching: Active

includes flexibility exercises performed by the patient without outside assistance from another individual Muscle spindle is stretched, but GTO do not fire; muscle resists relaxation Momentum can lead to overstretching, tearing

Kinetics

involves the forces, whether internal (e.g., muscle contractions or connective tissue restraints) or external (e.g., gravity, inertia, or segmental masses), that affect motion. When force is applied, distal segment may function independently or in unison with other joints.

Effect of Immobilization

prolongs repair and regeneration of damaged tissues Remobilization- early controlled mobilization speeds healing process

Speed

rate at which exercise is performed —Initially, exercises should be performed in a slow, deliberate manner at a rate of about 60° per second, with emphasis placed on concentric and eccentric contractions. —Exercise throughout the full ROM, pausing at the end of the exercise —Large muscle groups should be exercised first, followed by the smaller groups. —The exercise speed should be varied. —As strength, endurance, and power increase, functional movements should increase in speed

Phase 4: Focus

return to sport activity —Correct any biomechanical inefficiencies in motion —Restore coordination and muscle strength, endurance, and power in sport-specific skills Individual can return to their sport activity as soon as muscle strength, endurance, and power are restored

Kinesthesia

sensation of joint movement

Proprioception

sensation of joint position —A specialized variation of the sensory modality of touch that encompasses the sensation of joint movement (kinesthesia) and joint position —Sensory receptors located in the skin, muscles, tendons, ligaments, and joints provide input into the central nervous system (CNS) relative to tissue deformation —Visual and vestibular centers also contribute afferent information to the CNS regarding body position and balance —Cutaneous, muscle, and joint mechanoreceptors mediate the ability to sense body position

Establish Goals: Short

—Address the specific component skills needed to reach the long-term goals. —ATC and patient should discuss and develop the goals; individual must feel a part of the process because this may educate and motivate the individual to work harder to attain the stated goals. —Many sport-specific factors may affect goal development —Demands of the sport; position played —Time remaining in the season —Regular season versus postseason or tournament play —Game rules and regulations regarding prosthetic braces or safety equipment —Location, nature, and severity of injury —Mental state of the individual —Short-term goals are developed in a graduated sequence —Example: a high-priority short-term goal is the control of pain, inflammation, and spasm Specific subgoals —Include an estimated time table needed to attain that goal —Subgoals are time dependent but not fixed —Consider individual differences in preinjury fitness and functional status, severity of injury, motivation to complete the goals, and subsequent improvement Develop and supervise the treatment plan The therapeutic exercise program is divided into four phases. Termination of one phase and initiation of the next may overlap. Each phase has a specific role: Phase 1: the inflammatory response, pain, swelling, and ecchymosis are controlled Phase 2: regains any deficits in range of motion and begins to restore proprioception Phase 3: regains muscle strength, endurance, and power Phase 4: prepares the individual to return to activity Each phase should be supervised and documented; progress notes should be completed on a weekly or biweekly basis.

Cardio endurance

—Also known as aerobic capacity —Depends on the efficiency of the pulmonary and cardiovascular systems —If the individual returns to activity without a high cardiovascular endurance level, fatigue sets in quickly and places the individual at risk for reinjury

Endurance

—Begin with two to three sets of 10 repetitions, progressing to five sets of 10 repetitions, as tolerated —When able to perform 50 repetitions, 1 lb may be added, and exercise reduced to three sets of 10 repetitions —Exercises should be performed slowly, concentrating on proper technique

Flexibility: Golgi tendon organs

—Connected in a series of fibers located in tendons and joint ligaments —Respond to both contraction and stretch of the musculotendinous junction —If the stretch continues for an extended time (i.e., over 6 to 8 seconds), the Golgi tendons are stimulated—causes a reflex inhibition in the antagonist muscles —Mechanism protects the musculotendinous unit from excessive tensile forces

Muscular endurance: Plyometric Training

—Employs the inherent stretch-recoil characteristics of skeletal muscle —Initial, rapid eccentric (loading) prestretching of a muscle activates the stretch reflex. —This stretch produces a strong stimulus at the spinal cord level that causes an explosive reflex concentric contraction. —The greater the stretch from the muscle's resting length immediately before the concentric contraction, the greater the load the muscle can lift or overcome —Potential for injury if the individual does not have full ROM, flexibility, and near-normal strength —Performed every 3 days to allow the muscles to recover from fatigue Examples: Lower extremity—standing jump, multiple jumps, box jumps or drop jumping from a height, single- or double-leg hops, bounding, leaps, and skips Upper extremity—a medicine ball, surgical tubing, plyoback, and boxes

Establish Goals: Long

—Establish expected level of performance at the conclusion of the exercise program —Focus on functional deficits in performing activities of daily living (ADLs) —Examples of goals: bilateral, equal range of motion, flexibility, muscular strength, endurance, and power; relaxation training; and restoration of coordination and cardiovascular endurance

Frequency

—Exercise performed twice daily yields greater improvement than exercise done once. —The exercise program should be conducted three to four times per week in most cases. —Critical not to work the same muscle groups on successive days to allow recovery from fatigue and muscle soreness; if daily bouts are planned, strength and power exercises may be alternated with cardiovascular conditioning, or exercises for the lower extremity may alternate with exercises for the upper extremity

Specificity

—Exercise program must address the specific needs of the patient. —Example: exercises that mimic the throwing action will benefit a baseball pitcher but are not applicable to a football lineman; if exercises simulate actual skills in the individual's sport, the patient is more likely to be motivated and compliant with the exercise program —Type of exercise (i.e., isometric, isotonic, isokinetic) is also important; individuals who rely on eccentric loading must also include eccentric training in their rehabilitation program; velocity has also been shown to be specific to that required for the sport skill, with greatest strength gains consistently occurring at training speeds

Reassess progress of program

—Flexible enough to accommodate the progress of the individual —If short-term goal is achieved sooner than expected, a new short-term goal should be written. —Periodic measurement of girth, range of motion, muscle strength, endurance, power, and cardiovascular fitness will determine whether progress occurs. —If progress is not seen, the individual should be reevaluated; determine reasons for delay (e.g., physical problems, noncompliance, or psychological influences)

Dynamic Equipment

—Free weights Inexpensive Can be used in diagonal patterns for sport-specific skills Adding or removing weights from the bars can be troublesome A spotter may be required for safety purposes to avoid dropping heavy weights —Thera-Band, or surgical tubing Inexpensive Easy to set up Can be used in diagonal patterns for sport-specific skills Can be adjusted to the patient's strength level by using bands of different tension —Weight machines Weights can be changed quickly and easily Can perform circuit training Typically large and expensive Work only in a single plane of motion May not match the biomechanical makeup or body size of the individual

Muscular strength

—Improved with a minimum 3 days per week of training that includes 12 to 15 repetitions per bout of 8 to 10 exercises for the major muscle groups —If complaints of pain, swelling, or residual muscle soreness, the program may need to be decreased or varied in intensity —Orderly progression should move from range of motion exercises to isometric, isotonic, isokinetic, and functional activities progressing from low intensity to high intensity with ever-increasing demands on the patient as the healing process allows

Progression

—In an effort to maintain motivation and compliance, an objective improvement should occur each day, whether this is an increase in repetitions or intensity.

Coordination

—Involves a complex muscular interaction using the appropriate speed, distance, direction, rhythm, and muscle tension to execute the task —Two categories Gross motor movements —Involve large muscle groups —Activities such as standing, walking, skipping, and running Fine motor movements —Involve small muscle groups —Precise actions, particularly with fingers, such as picking up a coin off a table, clutching an opponent's jersey, or picking up a ground ball with a glove Coordination and proprioception are directly linked. When an injury occurs and the limb is immobilized, sensory input from proprioceptors and motor commands are disrupted, resulting in an alteration of coordination.

Flexibility: Muscle Spindles

—Lie parallel to muscle fibers —Stretch with the muscle —Innervated by both afferent and efferent fibers —Can detect not only muscle length, but more importantly, the rate of change in muscle length —When stimulated, the spindle sensory fibers discharge and, through reflex action in the spinal cord, initiate impulses to cause the muscle to contract reflexively, inhibiting the stretch

Isometric training

—Measures a muscle's maximum potential to produce static force —Muscle is at a constant tension whereas muscle length and joint angle remain the same Advantages: useful (1) when motion is contraindicated by pathology or bracing; (2) when motion is limited because of muscle weakness at a particular angle (sticking point); or (3) when a painful arc is present Disadvantages: least effective training method—strength gains are limited to a range of 10° on either side of the joint angle; potential for Valsalva effect—adverse, rapid increase in blood pressure occurs when the breath is held against a closed glottis Technique: maximal force is generated against an object for 10 seconds, repeated 10 times per set

Active Inhibition

—Muscle group reflexively relaxes before the stretching maneuver —Common methods include contract-relax, hold-relax, and slow reversal-hold-relax —Examiner stabilizes the limb to be exercised; alternating contractions and passive stretching of a group of muscles are then performed; contractions may be held for 3, 6, or 10 seconds

DOMS (delayed onset muscle soreness)

—Muscular pain or discomfort 1 to 5 days after unusual muscular exertion —Associated with joint swelling and weakness, which may last after the cessation of pain —To prevent the onset of DOMS, eccentric exercises should progress gradually —Dynamic muscle strength is gained through isotonic or isokinetic exercise

Proprioceptive exercises

—Must be specific to the type of activity that the individual will encounter in sport participation —Progression of activities to develop dynamic, reactive neuromuscular control is achieved through a progression that moves from slow-speed to high-speed, low-force to high-force, and controlled to uncontrolled activities.

DAPRE (daily adjusted progressive resistance exercise)

—Objective method of increasing resistance as the individual's strength increases or decreases —A fixed percentage of the maximum weight for a single repetition is lifted during first and second sets; maximum repetitions of the resistance maximum (RM) are lifted in third set; adaptations to the amount of weight lifted are then increased or decreased accordingly in fourth set and the first set of next session —Based on the concept that if the working weight is ideal, the individual can perform six repetitions when told to perform as many as possible; if the individual can perform more than six repetitions, the weight is too light; conversely, if the individual cannot lift six repetitions, the weight is too heavy —May not be appropriate for chronic injuries or early postoperative rehabilitation; high weights can potentially cause a breakdown of the supporting soft-tissue structures and exacerbate the condition

Ways to improve coordination

—Performing closed kinetic chain activities in phase 2 of the exercise program —Constant repetition of motor activities —Using sensory cues (i.e., tactile, visual, or proprioceptive) —Increasing speed of activity over time, can continue to develop coordination in phases 3 and 4 —Example: wobble board, teeter board, Pro Fitter, or BAPS board is often used to improve sensory cues and balance in the lower extremity; PNF patterns and the Pro Fitter also may be used to improve sensory cues in the upper and lower extremities

Overload principle

—Physiological improvements occur only when an individual physically demands more of the muscles than is normally required —Based on the specific adaptations to imposed demands (SAID) principle SAID principle —The body responds to a given demand with a specific and predictable adaptation —Achieved by manipulating intensity, duration, frequency, specificity, speed, and progression Intensity—reflects both the caloric cost of the work and the specific energy systems activated

Duration

—The estimated time it will take to return the individual to full (100%) activity, or more commonly to the length of a single exercise session —Time can shorten if pain, swelling, or muscle soreness occur —In general, at least 20 minutes of continuous activity with the heart elevated to at least 70% of maximal heart rate; particularly important when increasing cardiovascular endurance

Sport specific skill conditioning

—Therapeutic exercise should progress to the load and speed expected for the individual's sport —Example: a baseball player performs skills at different speeds and intensities than a football lineman —Exercises must be coupled with functional training, or specificity of training related to the physical demands of the sport work the affected extremity through functional diagonal and sport-specific patterns —Example: in phase 3, a baseball pitcher may have been moving the injured arm through the throwing pattern with mild-to-moderate resistance; in phase 4, the individual should increase resistance and speed of motion; working with a ball attached to surgical tubing, the individual can develop a kinesthetic awareness in a functional pattern; when controlled motion is done pain-free, actual throwing can begin; initially, short throws with low intensity can be used, progressing to longer throws and low intensity; as the player feels more comfortable and is pain free with the action, the number of throws and their intensity are increased —Other sport-specific skills that can be performed at this level include sprint work, agility runs, figure eights, side stepping, shuttle runs, and interval training (alternating periods of intense work and active recovery).

Reciprocal Inhibition

—Uses active agonist contractions to relax a tight antagonist muscle —The individual contracts the muscle opposite the tight muscle, against resistance; causes a reciprocal inhibition of the tight muscle, leading to muscle lengthening