Recurrent Ankle Sprain Prevention: Implications for Strength Training Interventions

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Recurrent Ankle Sprain Prevention Implications
for Strength Training Interventions

• 60th NATA Annual Meeting Clinical Symposia
• Thomas W. Kaminski, PhD, ATC, FACSM
• Professor
• Director of Athletic Training Education
• University of Delaware

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Knowledge

• One can never have too much knowledge.
  Knowledge leads to understanding, understanding
  leads to appreciation, appreciation leads to
  respect, and respect leads to appropriate
  application. The greater your understanding of
  the whys and how's, the less dangerous will
  be your application of the knowledge you posses
  
• Peggy A. Houglum

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Overview

• Importance of muscular strength and endurance
• Muscular stability
• Assessment of strength
• Current intervention trends
• A bit of research from our lab
• Is it working? --- what the research tells us ---
  show me the evidence!
• Future directions

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Can this be prevented?
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Basic Components of Therapeutic Exercise

• Flexibility and range-of-motion
• Strength and muscular endurance
• Re-establishment of proprioception and
  neuromuscular control

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Strength and Muscular Endurance Why are they
important?

• With any injury some strength is lost
• Dependent on
• Area injured
• Extent of injury
• Amount of time disabled
• Muscular Strength
• Maximum force that a muscle or group of muscles
  can exert
• Muscular Endurance
• Muscle's ability to sustain a submaximal force in
  either a static or repetitive activity over a
  period of time.
• Of all the parameters, strength is probably the
  most obvious and frequently sought following
  injury.
• Optimal muscle function is necessary for dynamic
  stabilization in the ankle

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Return to Play Guidelines

• No pain, swelling or atrophy
• Full ROM
• Normal flexibility
• Appropriate strength
• Adequate muscular endurance
• Perform sport skills and coordination tasks at an
  appropriate level

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Dynamic Muscular Stability in the Ankle

• Muscle strength and endurance are two dimensions
  within a continuum of muscle resistance.
• Muscles that control movements in the ankle
  region must work around the changing axes of
  motion associated with the biomechanics of the
  region.
• Co-contraction is important, especially eccentric
  control
• Loss of this efficiency may result in an
  inability to dissipate forces in a coordinated
  manner

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Components of Lateral Muscular Stability
Evertors

• Some argue that strength of the peronei is a
  central component in the treatment of ankle
  instability.
• Musculature
• Peroneus longus
• Peroneus brevis
• Function to evert and PF the foot.
• Provide lateral stability and help to maintain
  foot stability (PL).
• Tropp H. Pronator weakness in functional
  instability of the ankle joint. Int J Sports Med
  19867291-294.

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Components of Anterior Muscular Stability
Dorsiflexors

• Musculature
• Tibialis anterior
• Extensor hallucis longus
• Extensor digitorum longus
• Peroneus tertius
• Some recent interest in this muscle and ankle
  injuries (Witvrouw E. at al. The significance of
  the peroneus tertius muscle in ankle injuries. Am
  J Sports Med, 200634(7)1159-1163.)
• Absent in 5 - 17 of Caucasian population
• ? DF strength has been implicated as a risk
  factor for ankle sprain. (Willems et al.
  Intrinsic risk factors for inversion ankle
  sprains in male subjects. Am J Sports Med,
  200533(3)415-423.)

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Components of Posterior Musculature Stability
Plantar Flexors

• Least packed position
• Musculature
• Triceps surae
• Plantaris
• Tibialis posterior
• Flexor digitorum longus
• Flexor hallucis longus
• PB and PL
• Deficits in PF strength associated with ankle
  injury risk. (Baumhauer JF, et al. A prospective
  study of ankle injury risk factors. Am J Sports
  Med, 199523564-570.)

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Components of Medial Muscular Stability
Invertors

• Musculature
• Tibialis anterior
• Tibialis posterior
• Provide medial stabilization for the foot and
  ankle.
• TP acts as a sling to support the arch, along
  with help from the PL.
• Reports of invertor weakness in those with ankle
  instability
• Ryan L. Mechanical stability, muscle strength,
  and proprioception in the functionally unstable
  ankle. Aus J of Physio 19944041-47.
• Sekir U. et al. Effect of isokinetic training on
  strength, functionality and proprioception in
  athletes with functional ankle instability. Knee
  Surg Sports Traumatol Athrosc. 2006

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Assessing Dynamic Ankle Stability Isometric
Strength

• Simple and inexpensive
• Use of hand-held dynamometers
• Not very functional for dynamic strength
  assessments

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Assessing Dynamic Ankle Stability Isotonic
Strength

• Isotonic activities re dynamic and involve both
  ECC and CON muscle actions
• 1 RM is commonly used a measure of strength in
  larger muscle groups, however rarely used in the
  ankle.
• Some examples of isotonic exercises are shown
  here.

PrimUs System
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Assessing Dynamic Ankle Stability Isokinetic
Strength

• Isokinetic Dynamometry
• objective
• quantifiable
• quasi-CKC assessment
• reliable
• Capable of measuring both ECC and CON muscle
  actions

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Kin Com 125 APIsokinetic Dynamometer

• Concept introduced in 1967 by Hislop Perrine
  (Hislop, HJ, Perrine, JJ (1967). Phys Ther. 47,
  114-117.)
• Contemporary dynamometers enable the researcher
  to gather both CON and ECC data
• Allows for the examination of reciprocal muscle
  group ratios (knee, shoulder, ankle)

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So what do we do for this young lady?
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Rehabilitation Goals

• Combining OKC and CKC rehab techniques to regain
  normal motion, strength, and sensorimotor
  function.
• Balduini and Tetzlaff (Clin Sports Med 1982)
  suggest that although there is no consensus
  regarding ankle sprain rehab ---- the goal should
  be to decrease the incidence of AI!

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Current Strength Interventions from a Clinicians
Perspective

• 4-way HIP t-band kicks (a nice stress on the
  ankle musculature)
• Dynamic exercises (cuff weights, surgical tubing,
  resistive bands)
• Explosive/reactive manual resistance exercises
• Emphasis on EV/DF beginning with the foot PF,
  knee flexed, and hip IR

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Current Strength Interventions from a Clinicians
Perspective

• Toe raises, heel walks, toe walks
• Standing sideways on a slant board
• Use of unstable surfaces too
• With toe raises push a quarter into the floor to
  isolate the foot intrinsics
• Emphasis on many repetitions!
• Isokinetic training
• Dynamic strengthening plyometrics
• Single leg hopping exercises --- laterally for
  distance

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Freeman, MAR. Instability of the foot after
injuries to the lateral ligament of the ankle.
JBJS 1965 47B (4) 669-677.

• Freeman in this seminal paper stated
• no patient was found at the time of discharge
  to display any mechanical instabilities and/or
  calf muscle weakness. Therefore, in no case
  could late functional instability be attributed
  to these pathological processes.
• 40 years later is this still the pervasive
  viewpoint?

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A Public Health Issue?

• Cost of initial treatment and follow-up
  rehabilitation
• Strong link with an increased risk for
  osteoarthritis and articular degeneration

October 2004
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Muscle Weakness as a Cause of Ankle Instability

• Common Terminology
• peroneal muscle weakness
• pronator weakness
• evertor weakness
• calf dysfunction

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Strength and Ankle Instability

• Strength Deficits
• Decreases in inversion/eversion or plantar
  flexion/dorsiflexion strength?
• Functional strength ratios (involving both
  CONCENTRIC and ECCENTRIC muscle actions)?
• EI
• PFDF
• Time to peak torque (power)?
• Are the deficits due to
• Muscle damage or atrophy?
• Impaired NM recruitment ? functional
  insufficiency in the dynamic defense mechanism?

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Strength Assessment Research
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Early Research Reports

• Staples (1972, 1975) - peroneal weakness was
  found in a majority of those symptomatic ankles
  with ankle instability
• Primary criticism of these early research reports
  was the subjective nature in which strength was
  assessed utilizing MMTs

• Bonnin (1950) - the development of muscular
  control by the peronei should be encouraged
• Bosein et al. (1955) - peroneal muscle weakness
  was most significant factor contributing to
  recurrent ankle sprains

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A Comprehensive Isokinetic Strength Analysis in
those with Self-Reported Ankle Instability
T.W. Kaminski, FACSM, G.P. Gustavsen, Human
Performance Laboratory, Department of Health,
Nutrition Exercise Sciences, University of
Delaware, Newark, DEMedicine and Science in
Sports and Exercise, 38 (5), S-265, 2006.
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Conclusions

• ECC inversion muscle actions are important in
  controlling lateral displacement of the lower leg
  in a closed kinetic chain.
• Without this controlling mechanism in place,
  rolling over of the ankle is possible and
  sprains involving the lateral ligamentous
  restraints are imminent.
• Deficits in inversion ECC strength were apparent
  in the male subjects involved in this study,
  suggesting the need for intervention in those
  with ongoing ankle instability. Additional
  deficits, regardless of gender appear to involve
  both CON DF and ECC EV motions.
• Historically, ankle-strengthening exercises have
  targeted the lateral compartment musculature
  this study suggests that those routines should
  also include interventions directed at the
  anterior compartment musculature as well.

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More Recent Isokinetic Data

• 3 group analysis
• CONT, SPRAINER, AI
• Isokinetic measurements for PF, DF, Inv, and Ever
  (PT and ratios)
• Strength profile was less than AI and control
  groups but not statistically significant!

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Buckley, B.D., Kaminski, T.W., Powers, M.E.,
Ortiz, C., Hubbard, T.J. Using reciprocal
muscle group ratios to examine isokinetic
strength in the ankle A new concept. Journal of
Athletic Training (Supplement) 36 (2), S-93,
2001.
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Kaminski, T.W., Cousino, E.S. Examining
functional strength ratios between those with
ankle instability and a control group with
uninjured ankles. Journal of Orthopedic Sports
Physical Therapy, 35(5), A18, 2005.
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Purpose

• The purpose of this investigation was to
  determine if differences in average torque/body
  mass functional strength ratios existed between
  those with unilateral and self-reported AI and a
  group of subjects who have never suffered from
  ankle injury.

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Subjects

• 175 subjects
• 90 females and 85 males
• age 21.63.2 yr.
• height 171.98.8 cm
• mass 73.114.7 kg
• All AI subjects met the inclusion criteria and
  had no mechanical instabilities
• Control group subjects matched on age, ht, mass,
  activity

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Data Analysis

• AT/BM ratios were used in the data analysis
• Reciprocal muscle group ratios included
• CON Eversion to ECC Inversion (ECON IECC)
• traditional ratio, invertors acting ECC to slow
  lateral displacement of the tibia
• ECC Eversion to CON Inversion (EECC ICON)
• peroneals react ECC to slow the rate of inversion

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Results

• AT/BW Ratios
• ECON IECC
• ranged from .08 to 2.53 Nm/kg
• EECC ICON
• ranged from .16 to 6.80 Nm/kg
• ANOVA demonstrated no significant differences
  between the two groups or ankles
• Velocity main effect
• ECON IECC Ratios
• 30/sec gt 120/sec
• Range from .66 - .93
• EECC ICON Ratios
• 120/sec gt 30 sec
• Range from 1.41 1.88

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CON E ECC I Functional Strength Ratios
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ECC E CON I Functional Strength Ratios
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A Closer Look at the Ratios
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E (CON) I (ECC) Ratios

• Trend is for ratios to be lt 1.0 why?
• ECC strength values in the denominator will in
  most cases be greater than the CON values found
  in the numerator
• ? 40 greater force production ECC
• less CON force generated at the higher velocity
  (120/sec) lowers the ratios at the higher speeds
• Lack of normative values for comparisons

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E (ECC) I (CON) Ratios

• Trend is for ratios to be gt 1.0 why?
• ECC strength values in the numerator will in most
  cases be greater than the CON values found in the
  denominator
• ? 40 greater force production ECC
• Interesting to note that at the higher velocity
  (120/sec) that the ratios are elevated
• ECC force production in the ankle typically rises
  from the slower velocities to peak around 120/sec

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Discussion

• No differences in strength between groups and/or
  ankles
• Compensatory mechanism?
• Glick et al. (1976 - Am J Sp Med)
• Strong peroneus muscles appear to be important in
  supporting the ankle mortise for prevention of
  injury
• Tropp et al. (1985 - Am J Sp Med)
• Inversion lever created in STJ - varus thrust if
  muscles dont counter
• Bernier et al. (1998 - JOSPT)
• peroneals stabilize the ankle with each step

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Implications

• Normative values are needed to allow for
  meaningful comparisons
• Will prove useful for clinician
• rehab goals
• return to play guidelines
• Perrin (1993) suggests the use of CON to ECC
  ratios traditional
• Hertel (2000 - Sports Med) suggests ECC eversion
  to CON inversion
• Functional ratio Aagaard et al. (1998 - Am J Sp
  Med)

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Comparing Ratios

• How do our ratios compare to other studies?
• Baumhauer et al. (1995 - Am J Sp Med)
• CON EI ratios _at_ 30/sec 1.0
• Wilkerson et al. (1997 - JOSPT)
• optimal CON EI ratios _at_ 30/sec .70 - .90
• optimal CON EI ratios _at_ 120/sec .65 - .85
• Hartsell Spaulding (1999 - Br J Sports Med)
• used ECC/CON ratios for each individual motion
• Inversion (1.21 - 1.72) and Eversion (1.45 -
  2.20)
• Perhaps when testing in a non-functional mode
  (ie. isokinetics) the two groups look similar?

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Kaminski, T.W., Higgins, M.J.. Examining
end-range eccentric force in a group of subjects
with self-reported functional ankle instability.
Medicine and Science in Sports and Exercise, 36
(5), S-287, 2004.
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Purpose

• To determine if differences in end-range ECC
  inversion and eversion isokinetic force
  production exist between a group of subjects with
  FAI and a control group with no history of
  previous ankle injury.

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Data Analysis

• Average eccentric torque value served as the
  dependent measure
• Mixed model ANOVA was used to determine if
  differences existed between the two groups for
  both eversion and inversion motions

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Results

• No differences in ECC force production over the
  last 10 of motion between the two groups for
  either ankle motion
• Inversion (ankle x speed x group) F (1,28)
  .115, P .737
• Eversion (ankle x speed x group) F (1,28) .959,
  P .336

Eccentric Force (meanSD)
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Inversion ECC Force
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Eversion ECC Force
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Discussion

• Use of end-range isokinetic force production has
  been previously studied in throwing athletes ---
  ECC deceleration force of the rotator cuff
  muscles.
• Initial study examining end-range force
  production in the ankle musculature
• Intuitively one would expect that a lack of
  strength near the end-range in either inversion
  or eversion would make an individual more prone
  to sprain? Or lead to long-term instabilities?

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Discussion

• Trend toward lower ECC end-range force
  production in both ankles of the FAI group
• Especially at the low velocity (30/sec)
• Would a larger subject pool yield different
  results?
• From this data deficits in ECC strength do not
  exist between the 2 groups studied

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Kaminski, T.W., Douex, A.T., Kolar, K.E.
Examining power output following an acute bout of
intensive exercise in subjects with ankle
instability. Journal of Athletic Training
(Supplement) 40 (2), S-26, 2005.
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Procedures Isokinetic Testing

• Ankle inversion and eversion strength was tested
  at two velocities (30/sec and 120/sec) using a
  Kin Com 125 AP isokinetic dynamometer.
• Eversion range to 20 and inversion range to 25
• Both ECC and CON muscle actions were assessed
• 3-5 sub-maximal warm-up repetitions were followed
  by 3 maximal test repetitions using the overlay
  feature on the Kin Com

Modified FFP served to induce the fatigue
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Results Eversion Time to Peak Torque
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Results Inversion Time to Peak Torque

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Conclusions

• ECC inversion muscle force is necessary in
  controlling CKC lateral displacement of the lower
  leg.
• Differences in ECC inversion TPT were evident
  post-fatigue
• Quicker time to PT than pre-fatigue?
• Does this result in an over-correction in force
  production in individuals with AI?
• Did the fatigue state trigger a NM event
  resulting in this change in PT timing?

Normal stance
Invertors acting ECC to control lateral
displacement of the tibia
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Conclusions

• Peripheral mechanisms for fatigue have suggested
  that neural, mechanical, and energetic events
  could interfere with tension development and
  potentially cause injury.
• Functional Fatigue Protocol served as a useful
  model for producing fatigue in our subjects
• The implications of such an event (early timing
  of PT) during the sprain mechanism are subject to
  further speculation and study.

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Training Studies and FAI

• Studied the influence of 6 wks. of strength
  proprioception training on isokinetic strength
  ratios (CON E ECC I)
• ECC and CON AT and PT tested pre post
• There were no significant differences in average
  torque and peak torque E/I ratios of the
  functionally unstable ankle for any of the groups
  after training compared with before.
• Six weeks of strength and proprioception training
  (either alone or combined) had no effect on
  isokinetic measures of strength in subjects with
  self reported unilateral functional instability.

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Examining Some Additional Aspects of Strength
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Kaminski, T.W., Perrin, D.H., Arnold, B.L.,
Gansneder, B.M., Gieck, J.H., Saliba, E.N.
Concentric and eccentric force-velocity
relationships between uninjured and functionally
unstable ankles. Journal of Athletic Training
(Supplement) 31 (2), S-54, 1996.
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Ankle Eversion CON F-VR
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Ankle Eversion ECC F-VR
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Functional Strength Concept

• Isolated eccentric, concentric or isometric
  actions are not natural or functional to sport.
• Measuring the stretch-shortening cycle (SSC) in
  isolated muscle groups could give a better
  indication of how each muscle group will perform
  during functional activities
• Helgesen Gajdosik (1993)
• Sport specific motions (running, cutting,
  jumping) meet the criteria of the SSC where an
  eccentric action is immediately followed by a
  counter concentric contraction in a working
  muscle.

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The Stretch-Shortening Cycle

• A concentric action immediately preceded by an
  eccentric action is more powerful (possibly 100)
  than a concentric action alone. (Svantesson et
  al. 1991)
• SSC Phases
• ECC
• amortization phase
• CON
• Release of stored energy within the elastic
  properties of the muscle (Cavagna, 1965)
• Muscle spindle stretch-reflex

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Is there a link between the SSC and FAI?

• Is the stretch-reflex delayed in individuals with
  FAI? (Konradsen et al., Brunt et al., Lofvenburg
  et al.)
• May be related to a deficiency in muscle spindle
  afferent which affects the stretch-reflex.
• Perhaps, the quicker the athlete is able to
  switch from yielding eccentric work to overcoming
  concentric work, the more powerful their response
  to the inversion and/or plantar flexion motions
  will be.
• Majority of lateral ankle sprains occur via this
  mechanism.

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Summary of Studies Examining Isokinetic Strength

• Isolated eversion strength deficits do not appear
  to be evident in those with AI
• EVCONINVCON ratios higher in the AI group,
  however not statistically different
• Conclusions
• Adaptive mechanism
• peroneal activity during gait cycle
• athletic activities help maintain strength
• Deficits at other points in the kinetic chain?
• Weakness not a factor in AI?
• Is the synergy between PL and TP disrupted?

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Consistency in Reporting Isokinetic Strength
Values

• Needed to establish a database of normative
  values for comparison
• EI ratios
• ECCCON ratios
• PT vs AT
• normalized for body mass

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How can clinicians/researchers reach a common
ground?

• Report strength values relative to body weight
  (mass) to account for gender size differences
• Wilkerson (1997) has advocated using average
  power
• rate at which tension is developed is as
  important as the magnitude
• Refine the AI criteria to more accurately
  describe the condition and work with a
  homogeneous group of subjects

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Finally - Systematic Reviews to Tell Us What is
Really Going On?
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Holmes Delahunt, Sports Med, 2009

• Consensus in the literature is that evertor
  strength deficits are not a common finding is
  subjects with AI
• Despite this consensus peroneal strengthening
  continues to form a central component of ankle
  injury rehab!

• Some have suggested it might be lack of peroneal
  muscle endurance or ineffective timing
• Invertor weakness selective inhibition
  (arthrogenic muscle inhibition)

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Holmes Delahunt, Sports Med, 2009
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Arnold et al. Meta-Analysis, JAT in press 2009

• Evertor strength differences are present between
  stable and unstable ankles
• When put into appropriate units of measure
  (Newtons) these differences are meaningful
• Best to test at one velocity (slower)
• Believe that strength assessments and strength
  training are indeed IMPORTANT parts of RTP
  criteria and rehabilitation!

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Clinical Implications

• Muscle damage probably has not occurred, rather
  inefficient NM control is probably responsible
  for any deficits that we might encounter
• Advocate muscle strengthening involving all 4
  sectors of dynamic ankle stability
• Pay particular attention to the eccentric
  component of muscle actions
• E/I ratios may be important in the identification
  of ankle injury risk
• Strength measures SHOULD remain as part of the
  criteria for return to play

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Where Do We Go From Here?

• Others ways of assessing strength components of
  function
• Rate of force development
• Force-Velocity Relationships (F-VRs)
• Proprioceptive measures
• Force sense
• (Arnold et al Contralateral force sense deficits
  are related to the presence of functional ankle
  instability. J Orthop Res. 2006 Jul24(7)1412-9.

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Oh NO, not again!
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Todays lecture can be viewed at the following
URL addresshttp//www.udel.edu/HNES/AT/Site/lec
tures.html
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Thank You