Chapter 8: Regaining Stability and Balance

1. Chapter 8: Regaining Stability and Balance Jenna Doherty-Restrepo, MS, ATC, LAT Rehabilitation Techniques in Athletic Training

2. Balance • Factors that impact balance • Muscular weakness • Proprioceptive deficits • ROM deficits • Balance is critical in dictating movement strategies within the closed kinetic chain • Vital component in rehabilitation • Proprioception and Kinesthesia

3. Postural Control System • Components • Sensory detection of body motions (Feed-forward) • Execution of musculoskeletal responses (Feedback) • Balance is a static and dynamic process • Disrupted balance occurs due to two factors • Position of CoG relative to base of support is not accurately sensed • Automatic movements required to maintain the CoG are not timely or effective

5. Body position in relation to gravity is sensed by • Visual • Vestibular • Somatosensory inputs • Balance movements involve a number of joints • Ankle • Knee • Hip • Coordinated movement along kinetic chain

6. Control of Balance • Postural control relies on feedback • CNS involvement • Sensory organization • Determines timing, direction and amplitude of correction based on input • System relies on one sense at a time for orientation • Muscle coordination • Collection of processes that determine temporal sequencing and distribution of contractile activity • Balance deficiencies • Inappropriate interaction among 3 sensory inputs • Patient that is dependent on one system may be presented with inter-sensory conflict

7. Sensory Input • Somatosensory • Provides information concerning relative position of body parts to support surface and each other • Vision • Measures orientation of eyes and head in relation to surrounding objects • Role in maintenance of balance • Vestibular • Provides information dealing with gravitational, linear, and angular accelerations of the head with respect to inertial space • Minor role when visual and somatosensory systems are operating correctly

8. Proprioception/Kinesthesia • Specialized variation of the sensory modality of touch, encompassing joint sense and position • Process • Input is received from mechanoreceptors • Stretch reflex triggers activation of muscles about a joint due to perturbation • Results in muscle response to compensate for imbalance and postural sway • Muscle spindles sense stretch in agonist, relay information afferently to spinal cord • Information is sent back to fire muscle to maintain postural control

9. Closed Kinetic Chain • Balance • Process of maintaining body’s CoG within base of support • CoG rests slightly above the pelvis • Kinetic chain • Each moving segment transmits forces to every other segment • Maintaining equilibrium involves the closed kinetic chain • Foot = distal segment (fixed beneath base of support)

10. Balance Disruption • Body must be able to determine what strategy to utilize in order to control CoG • Joint mechanoreceptors initiate automatic postural response • Selection of Movement Strategy • Joints involved allow for a wide variety of postures that can be assumed in order to maintain CoG • Forces exerted by pairs of opposing muscles at a joint to resist rotation (joint stiffness) • Resting position and joint stiffness are altered independently due to changes in muscle activation

11. Ankle Strategy • Shifts CoG by maintaining feet and rotating body as a rigid mass about the ankle joints • Gastrocnemius or tibialis anterior are responsible for torque production about ankle • Anterior/posterior sway is counteracted by gastrocnemius and tibialis anterior, respectively • Effective for slow CoG movements when base of support is firm and within LOS • Also effective when CoG is offset from center

12. Hip Strategy • Relied upon more heavily when somatosensory loss occurs and forward/backward perturbations are imposed • Aids in control of motion through initiation of large and rapid motions at the hip • Effective when CoG is near LOS perimeter and when LOS boundaries are contracted by narrower base of support • Stepping Strategy • Utilized when CoG is displaced beyond LOS • Step or stumble is utilized to prevent a fall

13. Balance and Injury • Damaged tissue results in reduced joint ROM causing a decrease in the LOS • Greater risk for fall • Research indicates that sensory proprioceptive function is affected when athletes are injured

14. Assessment of Balance • Subjective Assessment • Traditionally assessed via the Romberg Test • Feet together, arms at side, eyes closed • Loss of proprioception is indicated by a fall to one side • Balance Error Scoring System (BESS) • Utilizes three stances • Double, single, tandem on both firm and foam surfaces • Athletes are instructed to remain motionless with hands on hips for 20 seconds • Unnecessary movements and correction of body position are counted as ‘errors’ (max score = 10) • Results are best utilized if compared to baseline data

16. Assessment of Balance • Semi-dynamic and Dynamic Balance tests • Functional reach tests • Timed agility tests • Carioca • Hop test • Timed T-band kicks • Timed balance beam walks (eyes open and closed)

17. Injury and Balance • Stretched/damaged ligaments fail to provide adequate neural feedback, contributing to decreased proprioception and balance • May result in excessive joint loading • Could interfere with transmission of afferent impulses • Alters afferent neural code conveyed to CNS • Decreased reflex excitation • Caused via a decrease in proprioceptive CNS input

18. Ankle Injuries • Joint receptors damaged during injury to lateral ligaments • Results in Articular Deafferentation • Diminished signaling via afferent pathways • Reason behind balance training in rehabilitation • Orthotic and bracing intervention • Enhance joint mechanoreceptors to detect perturbations and provide structural support for detecting and controlling sway • Chronic ankle instability • Recovery of proprioceptive capabilities • Instability vs. Deafferentation

19. Knee Injuries • Ligamentous injury alters joint position detection • ACL deficient subjects with functional instability exhibit this deficit (persist to some degree after reconstruction) • May also impact ability to balance on ACL deficient leg • Mixed results have been presented with static testing • Isometric strength could compensate for somatosensory deficits • Definition of functionally unstable may vary • Role of joint mechanoreceptors with respect to end range and the far reaches of the LOS • More dynamic testing may incorporate additional mechanoreceptor input • Results may be more definitive

20. Head Injuries • Balance has been utilized at a criterion variable • Additional testing is necessary in addition to balance and sensory modalities • Postural stability deficits • Deficits may last up to three days post-injury • Result of sensory interaction problem - visual system not used effectively • Objective balance scores can be utilized to determine recovery curves for making return to play decisions

21. Balance Training • Vital for successful return to competition from lower leg injury • Possibility of compensatory weight shifts and gait changes result in balance deficits • Functional rehabilitation should occur in the closed kinetic chain – nature of sport • Adequate and safe function in the open chain is critical = first step in rehabilitation

22. Rules of Balance Training • Exercise must be safe and challenging • Stress multiple planes of motion • Incorporate a multisensory approach • Begin with static, bilateral, and stable surfaces and progress to dynamic, unilateral, and unstable surfaces • Progress towards sports specific exercises • Utilize open areas • Assistive devices should be within arms reach • Sets and repetitions • 2-3 sets, 15 sec.  30 sec. repetitions • 10 sets, 15 sec.  30 sec. repitions

23. Classification of Balance Exercises • Static • CoG maintained over fixed base of support on stable surface • Semi-dynamic • CoG maintained over fixed base of support while on a moving surface • CoG transferred over fixed base of support in selected ranges and/or directions within the LOS while on a stable surface • Dynamic • CoG maintained within LOS over a moving base of support while on a stable surface (involve stepping strategy) • Functional • Same as dynamic with inclusion of sports specific task

24. Phase I • Non-ballistic types of drills • Static balance training • Bilateral to unilateral • Utilize multiple surfaces to safely challenge athlete • With and without arms/counterbalance • Eyes open and closed • Alterations in various sensory information • ATC can add perturbations • Incorporation of multiaxial devices

25. Bilateral Stance Exercises

26. Phase II • Transition from static to dynamic • Running, jumping, and cutting • Activities that require the athlete to repetitively lose and gain balance in order to perform activity • Incorporate only when sufficient healing has occurred • Semi-dynamic exercises should be introduced in the transition • Involve displacement or perturbation of CoG • Bilateral, unilateral stances or weight transfers • Sit-stand exercises, focus on posture

27. Unilateral Semi-dynamic exercises • Emphasize controlled hip flexion, smooth controlled motion • Single leg squats, step ups (sagittal or transverse plane) • Step-Up-And-Over activities • Introduction to Theraband kicks • Balance Beam

28. Phase III • Dynamic and functional types of exercise • Start with bilateral jumping drills (straight plane) • Advance to diagonal jumping patterns • Increase length and sequences of patterns • Progress to • Unilateral drills, vertical drills • Addition of implements • Tubing, foam roll, etc… • Final step = functional activity • Subconscious dynamic control/balance

29. Phase III Exercises