Tendons Structure, pain and function. Structure. Lecture Presentation Professor Jill Cook Exercise rehabilitation for lower limb tendinopathy 1

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1 Exercise rehabilitation for lower limb tendinopathy 1 Tendons Structure, pain and function Jill Cook La Trobe Sport and Exercise Research Centre Monsters Melbourne Tendon Research Structure Normal or excessive load +/- individual factors Unloaded tendon Optimised Unloaded load Normal tendon Excessive Appropriate load + individual modified factors load Reactive tendinopathy Optimised Load Adaptation Strengthen Tendon dysrepair Degenerative tendinopathy Reactive-on-degenerative tendinopathy

2 Exercise rehabilitation for lower limb tendinopathy 2 Normal tendon Reactive tendinopathy Tendon dysrepair Degenerative tendinopathy Cells activated and increased proteoglycans increased + Matrix disruption by increased PGs, Opportunity for vascular ingrowth + Cell death can occur, islands of matrix degeneration, neovascularisation What are common clinical presentations? Reactive after unloading Unloading decreases tendon mechanical properties and tendon capacity to tolerate load Present after a period of time off Injury, off season Return to loading at previous levels Tendons respond to load Most commonly occurs in already pathological tendons Re injury Development of PT Normal or excessive load +/ individual factors Unloaded tendon Normal Degenerative tendon tendon Reactive on degenerative Reactive tendinopathy tendinopathy Structure, pain, function interaction Unloaded tendon with low capacity Degenerative non painful (older person, postinjury), susceptible to Pathology and pain with loss tendon with poor function, of function can rupture overload and pathology and pain When does structure matter? Normal Pathological (n = 36) (n = 30) AP diameter (mm) 6.5 ± ± 1.5 mcsa of DIS (mm 2 ) 1.4 ± ± 8.3 Poor function Pain Pathology mcsa of AFS (mm 2 ) 80.8 ± ± 26.5 Imaging normal painful tendon, rare, differential diagnosis Degenerative non painful tendon with good function, can rupture So typical degenerative structure may not matter at all Not load bearing Tendons have plenty of normal tissue Docking and Cook 2015

3 Exercise rehabilitation for lower limb tendinopathy 3 Transcranial Magnetic Stimulation Pain Lateral corticospinal tract Magstim Motor evoked potential in normal people 200 V 25 ms 9 th October, Tendon pain Motor drive in tendinopathy completely different Hyper excitable motor cortex Excess inhibition Figure 1 Recruitment curve for normal and tendinopathy tendons So what does this mean for our athletes with tendinopathy? That they have all their motor cortex on They moderate output using excess inhibition Likely to be less effective, less precise, harder work

4 Exercise rehabilitation for lower limb tendinopathy 4 So where do isometrics fit? We know that load is good But this was a severely pathological, painful and unloaded tendon We know that isometric load is unlikely to irritate the tendon cells Took timing from bone loading Tried isometric exercise with heavy loads Other things helped Managing frequency of load Short acting CSI What does isometrics do to pain and the brain? Reduces pain More than isotonics Longer than isotonics Reduces cortical inhibition Returns inhibition to normal Mean 19% stronger after isometrics Figure 2 Pain reduction on the single leg decline squat with isometric and isotonic exercise for patellar tendon What is high tendon load? Load Tensile load Any activity that requires the tendon to store and release energy Anything else is easy for a tendon High weights, eccentric movement

5 Exercise rehabilitation for lower limb tendinopathy 5 What about compressive loads? At the fulcrum Gluteus medius/minimus Achilles insertion Supraspinatus Adductor longus Hamstring (upper) Tibialis posterior At malleolus Peroneals Quadriceps Femoral condyle in deep knee flexion Combination loads induce tendinopathy Rat model three groups Tensile overload, compression only, compression and tensile overload Injury worst in the tensile and compression rats Next tensile overload Compression minimal effect by itself Soslowsky et al 2002 What happens if we load the tendon? No to load No Transient No lasting effect,? normal and happens all the time Load Adaptive Induces mechanical/ structural change Pathological Overwhelms tendon homeostasis / Reactive pathology Patellar tendon 5 day multi game tournament No Van Ark et al 2014 Type 1 diabetics and matched controls 10km fun run No and no difference Wong et al 2014

6 Exercise rehabilitation for lower limb tendinopathy 6 Transient to load Adaptive to load? Achilles tendons across Australian football preseason Progressive loading environment Over 3 months Structure improved Grigg et al 2009 Normal tendon Optimised Load Adaptation Strengthen Docking et al 2012 Pathological to load? 3 players in the preseason Achilles became symptomatic 2 recovered with change in load Reactive Diffuse changes? Dysrepair in player 3 Focal changes Unload reload Injury/illness TSB >200% Highest acute average all year Load 7 per. Mov. Avg. (Load) 28 per. Mov. Avg. (Load) 0 Injury risk Injury Most common scenario. Importance of maintaining load in off season Present modelling predicts increase in weekly load safe at around 107%/wk

7 Exercise rehabilitation for lower limb tendinopathy 7 So.. Tendons respond to load Mainly through mechanical sensitivity of resident (and recruited) cells Protein and cytokine production We don t know how much load will elicit the right Response vs adaptive vs pathological Likely varies between tendons and individuals (and bears) Management So what can we do? An athlete with poor function will always have pain An athlete with good function is protected from pain Therefore Improvement in function will nearly always improve pain How do we improve function We nearly always need good energy storage capacity Exception older people with low level function Those who play golf or walk for exercise Remember that the Achilles is still energy storing at these low levels of function Nearly always need to be rehabilitated back to this level

8 Exercise rehabilitation for lower limb tendinopathy 8 How do we improve function? Determine the start point Determine the end point Work from the start to the end In VERY small steps because tendons are sensitive to change Work from strength through power to energy storage Build in endurance and compression So, in summary Changing function will change pain Changing pain is what people come to you for Changing structure is not associated with change in pain Therefore change function in people with tendinopathy Dependent on the tendon, the activity and the person Play football Needs endurance Speed Repeated loading High energy storage Poor strength Muscle wasting Poor endurance Pain with energy storage loads Achilles tendon

9 Exercise rehabilitation for lower limb tendinopathy 9 Phase one: Isometrics Indications Implementation Considerations Reactive Reactive on degenerative Build up (> 45 seconds X 5) 4 5 X / day Think panadol 2 mins rest between is important Range appropriate to tendon Usually mid range Achilles different range for midsubstance V insertion, treat plantaris like insertion No tendon bounce / postural perturbations Single leg if possible Can start stage 2 other side, rest of kinetic chain How we use it in tendons Sustained contraction Away from compression Heavy loads Needs to be machine based is possible Don t be shy with load Avoid exercise that requires postural control Do 3 4 times a day if needed sec holds, 4 5 times Immediate and sustained pain relief Phase two: strength Indications Implementation Considerations Pain is stable on morning test Pain is settled from peak 4 X 6 8 Slow Heavy Single leg Isotonic exercises Isolated muscle exercises best No place for multi joint, bilateral exercises squats Examples weighted calf raises, leg extension Kinetic chain Address deficits Add functional exercises Once weights are good Add endurance Avoid compressive loads Avoid speed Encourage evening to avoid calf fatigue during day Phase three: energy storage Indications Implementation Considerations Pain is stable on morning test (may not be zero) Symmetry in mm bulk? This may takes a long time Good strength eg 25 raises single leg, 1.5 X BW on leg press, addressed deficits Every 2 3 days & assess Must keep strength going Consider as much a neural reprogramming as muscle/tendon function Faster NEVER with added load Body weight only Eccentric movement Stairs, split squats, skipping Add / change one thing at a time Break up absorption and propulsion phase early, add these together later in Phase 3..

10 Exercise rehabilitation for lower limb tendinopathy 10 Patellar tendon tensile load and loading rate in typical activities Phase four: energy storage and release Loading rate Bwsec 1 Indications Implementation Considerations Pain is stable on morning test (may not be zero) Good strength eg 25 raises single leg, 1.5 X BW on leg press, addressed deficits Dealing with power Every 2 3 days & assess Add / change one thing at a time May mix phase 3 and 4 exs Consider tendon capacity 20 0 leg press 3times BW land from jump land in a stop jump sequence Reeves 2003, Janssen 2013, Edwards 2012 Duration Frequency Change direction Speed Return to training and play Additional points Continue isometrics before exercise even when pain has settled Address the cortical inhibition Maintain isotonics for strength throughout the program Continue for many months after return to sport? Persistent cortical inhibition Unloading The end