Eccentric Exercise & Neuromuscular Rehabilitation of the Athlete

Transcription

1 Eccentric Exercise & Neuromuscular Rehabilitation of the Athlete Overuse Injury at Epidemic Levels Facts about Strength Training Tendinopathy Muscle Weakness Eccentric Loading and tendon / muscle rehabilitation Neuromuscular Rehabilitation-Ballistic and Plyometrics Eccentric loading Robert Donatelli PT PhD Drbob@modernathleticscience.com Common Running Overuse Injuries Anterior Knee Pain Groin Strains Hamstring Tears Hip trochantric bursitis Achilles Tendinopathy Plantar Fasciitis Tibial Stress Syndrome Stress Fractures 1

2 Factors Leading to Overuse Predisposing * Excessive pronation, rotn deformities of LE, Muscle imbalances, Asymmetry Precipitating * training errors Excessive mileage Perpetuating *High intensity workouts do not allow tissue to recover Poor Shock Absorption Hip Muscle Deficits Poor Mechanics Poor Attenuation A. Ground Reaction force vector = varus moment B. Abd weakness varus knee C. Compensation = Valgus knee Force attenuation by soft tissue structures Hip extensors, abductors external rotators Quadriceps mechanism Eccentric Hamstring loading Achilles tendon Plantar fascia 2

3 Strength Training In Rehabilitation Evaluation of Muscle Imbalances Weakness of antagonist vs antagonistic Muscle Tightness Muscle and Soft tissue Myofascial pain-trigger points Early in the Rehabilitation Eccentric loading contraindicated No pain higher reps early Progression in demands on the tendon and muscle Facts About Strength Training Strength -Measure of human performance -Max force a muscle or muscle group can generate a specific velocity Strength training bilateral Hortobagyi et al, found increases as high as 104% during eccentric muscle action in the untrained limb. Neuromuscular changes (Early Temporary) Decreased co-contraction of antagonist Expansion in size of neuromuscular junction indicating greater Presynaptic Neurotransmitter and postsynaptic receptors Greater synchronicity in MU discharge effecting increase rate of peak force (muscle power) 3

4 Strength Training Facts Muscle Adaptations Muscle hypertrophy detected after 6-8 wk training. Prolonged Resistance Contractile adaptations Hypertrophy of the whole muscle 5-8% and the myofibers 25-35% Fiber Type Adaptations Greatest increase in # of IIA and growth, followed by IIX and least hypertrophy of Type I Strength Reps, Sets, Resistance 3 sets of 2-3 exercises specific to the muscles that need strengthening 3-6 reps most effective for increasing max dynamic strength 3 reps = 92.5% 1RM / 6 reps = 85% 1RM 6-12 reps target muscle hypertrophy/ best combination of load and volume 15 reps rarely increases max strength muscle endurance = 60% 1RM Strength is the Ability of the muscle to Produce Force Increase Muscle Strength: Increase speed Increase endurance Increase function -Measure of human performance -Max force a muscle or muscle group can generate at a specific velocity 4

5 Power is the functional application of both Speed and Strength Speed is a more innate quality that changes little with training Endurance The capacity to sustain repeated muscle actions Endurance is increased thru gains in strength and changes in local metabolic and circulatory function Type I Type II(A) 5

6 Functional Exercise R. Donatelli PhD PT A functional exercise is defined as an exercise specific to the muscle groups that are weak and the muscles that are important to the activity the patient wishes to return to Sufficient resistance, repetitions, and sets are used to stimulate the muscle to adapt by increasing strength. Correcting muscle imbalances and relieving the etiology of muscle dysfunction Intensity as a percentage of 1RM 100% = 1RM 95% 1RM = 2 RM 90% 1 RM = 4 RM 85% 1 RM = 6 RM 80% 1 RM = 8 RM 75% 1RM = 10RM 70 % 1Rm = 12 RM 65% 1RM = 14RM 60% 1 RM = 15-30RM 6

7 Fiber Type Transitions The patterns of neural stimulation dictates fiber type adaptations to anaerobic training I Ic IIc IIac IIa IIax IIx Myosin heavy chain expression IIa IIx Training of High-threshold motor units actives transition from IIx to IIa IIx change their myosin (ATPase) isoform content to more oxidative IIa fibers more fatigue resistant = HIRT Early Muscle Changes in Strength Training Staron RS et al Skeletal muscle adaptations during early phase of heavyresistance training in men and women Am Physiol Soc 94 8 weeks high intensity resistance training (HIRT) Squat-Leg Press-Leg extensions 2x/per week 2set warm-up/ IRM alter Wed 3 sets 6-8 reps Mon Friday Strength improvement at 4 wks 9wks IIb to IIa 2 wks females 4 wks Males After 20 wks of HIRT very few type IIX fibers remain 16.2% pre / 2.7% post After 6 wks of HIRT, CSA increase in all fiber types. Significant reduction in type IIX 24.9% 7

8 Tendon Energy Generating Spring Eccentric loading Each of these musculotendinous units absorbs power by stretching (eccentric action) just before it generates power by shortening The change in length results from the stretch and recoil of the tendons Muscles function as tensioner of the tendon Tendon is an excellent biomechanical spring. Achilles Tendon Spring Achilles Tendon: Stretches during the first 1/2 of stance phase and recoils later in a spring-like fashion. Stores energy as stretched and returns 90% of this energy at push-off. Peak forces in the Achilles tendon, 6 to 8 x body weight. 8

9 Pathophysiology of tendon function Tendons are stronger than muscles and withstand larger forces Tendons that go around corners subjected to greater strain and interference with their blood supply Max load capacity and resistance to tears peak in the third decade and decrease with age Tendinopathy Facts Tendon injuries account for 30-50% of injuries in sports Overuse of tendons result in 30% of all running injuries and 40% of elbow injuries in tennis Patellar tendinopathy occurs 32-45% of basketball and volleyball players 9

10 Tendon Loading Increases Collagen Synthesis & Degradation Tendinopathy in athletes, Reinking PT in Sports 2012 Collagen Synthesis peaks around 24 hr after exercise and remains elevated up to 72 hours (Magnusson, Langberg, & Kjaer, 2010). Degradation of collagen is also increased after exercise, greater level than the increase in synthesis. The first 36 h after exercise, the collagen metabolic system is in a negative balance with degradation greater than synthesis This may explain that repeated exercise without sufficient rest repeated collagen breakdown, overuse injury. Complete rest through immobilization of a joint has a negative effect on tendon strength Tendinopathic Iceberg Fredberg and Stengaard-Pedersen (2008) challenged the tendinitis myth described a tendinopathic iceberg with a long period of time of asymptomatic changes in tendon with the exposed tip of the iceberg being a painful tendon. Abate et al. (2009) proposed tendinopathy beginning with overuse leading to microdamage of the tendon, followed by inadequate tendon healing, including neovascularization, nerve in growth, tendon degeneration, and, ultimately, a painful tendon at the tip of the iceberg. Cook and Purdam (2009) pathological model of the tendinopathy continuum with three stages: reactive tendinopathy, tendon disrepair, and degenerative tendinopathy 10

11 Pathological Breakdown of the Tendon Tendinopathy Immediately after training catabolism (protein breakdown) followed by protein synthesis Chronic overtraining may contribute to an extended state of catabolism (autoimmune reaction) Ohberg et al 2001 Tendenosis non inflammatory condition of collagen breakdown and disorganization, abnormal growth of capillaries into the tendon, calcification. If further micro trauma occurs before tendon is healed, excessive strain may cause tendon cells to die poor healing Chronic Achilles tendonitis precursor to a rupture Tendinopathy Evaluation and Rx Symptoms develop gradually with increasing training volume and/or intensity Pain and stiffness worse first step out of bed and improve as they get moving Pain at the beginning of activity and reduced during the performance, Progress to pain thru-out 11

12 Positive changes tendon structure and mechanical properties with Eccentric Loading Shalabi - Alfredson protocol. 12 reps 12 Sets over 12 weeks Subjects tendons were measured via MRI post eccentric loading reduced pain -reduction in fluid content of the tendon -increased healthy collagen deposition. Langberg found that Type I collagen synthesis increased after eccentric training in a group of twelve soccer players with unilateral Achilles Tendenosis indication of tendon healing. (Initial collagen Type III) Achilles Tendinopathy Shalabi et al AJSM 2004 post eccentric training decreased tendon volume and intratendious signal = reduced pain and improved performance. Increased Type I collagen after eccentric training Decreased tendon thickness = normalization of tendon structure Öhberg et al (2004): 12 week eccentric training tendon thickness, normalized tendon structure 12

13 Eccentric Loading Protocol Achilles Tendon Alfredson et al AJSM sets 15 reps bent knee & straight knee calf raises 2 times per day, 7 days per week 12 weeks Athletes were told to work thru pain unless disabling Load increased 5kg increments once training with body weight was pain free. Eccentric Training Protocol Patella Tendon Curwin In Athlete Injuries & Rehab 1996 When performing 3sets of 10 reps progress reps Athlete should experience pain and fatigue Load is increased until symptoms appear Pain before reps would be accompanied by worsening of symptoms load or speed should be decreased If there is no pain after 30 reps the stimulus is inadequate increase speed & load 13

14 Anterior Knee Pain Evidence based Treatment Approach Kongsgaard, J Med Sci Sports 2009 Eccentric loading 3x s wk 4 sets 15reps 12RM RM 4-5 wk 8RM 6-8 wk 6RM 9-12 wk Pain during exercise was acceptable no increase in pain following cessation of strength training. Single leg press hack squat- leg press Eccentric decline squat (single leg on wedge) Eccentric decline squat superior results at 12 months compared with traditional eccentric protocol for patellar tendinopathy in volleyball players Young Br. J Sports Med 2005 Decline squat protocols were effective in the treatment of tendon pain and sporting function in athletes with patellar tendinopathy Over 12 month period the decline squat protocol gave more significant relief than Step squat. Decline Squat 14

15 Patellar Tendinopathy in Athletes jumpers knee Schiavone, AJSM 2000 Strengthening of the quad gentle eccentric exercises to allow gradual adaptation of the muscle-tendon unit to greater loads Patella tendinopathy degenerative changes at the bone tendon junction and Mid-substance Tendon Early intervention is critical first onset of symptoms Stage 2 disease excellent results Stage 3 disease less than 50% success Hamstring Strain The most common injury sustained by athletes, currently the most common in professional soccer 29% of the injuries in track and field Common in sports that require maximum sprinting, kicking, acceleration and change in direction. 15

16 Eccentric Component of Exercise 2-3x greater EMG Delayed Fatigue 75% less Oxygen Lower ATP/CP less perceived effort Less muscle activity to maintain the same amount of force Greater heat production Reduced BP Force production in skeletal muscle is highest during negative work, maximizing increases in Fiber CSA Tendon Strengthening Eccentric Muscle Damage Eccentron DOMS muscle damage Stem cell in musclesatellite cell Protective repetitive bout effect Sarcomeres in Series Greater tension in muscle than during shortening 16

17 Muscle Damage DOMS High Speed Eccentric Loading Stretching of active muscle at high speeds and at lengths beyond optimum does not involve uniform lengthening of sarcomeres, but more closely resembles popping of sarcomeres, one at a time, in order from weakest to strongest. This leads to damage. Muscle Damage with Eccentric Loading Reduced strength (50-65% lasting 1-2 wks) most valid and reliable measures of Muscle Damage The repeated bout effect results in protective adaptation to the muscle 17

18 Muscle Protective Adaptation of Muscle Eccentric Exercises Muscle grows more sarcomeres in series. This causes a greater optimum length. More sarcomeres for the same muscle length leads to shorter sarcomeres, avoids extension beyond optimum length, avoids non-uniformities and so damage. Sarcomere in Series Sarcomere in series achieved with eccentric training More resistant to MD by more sarcomeres function at short lengths avoiding over-extending the muscle 18

19 Early application of Negative Work via Eccentric Ergometry Following ACL Case study JOSPT May 2006 Gerber et al. Semi-tendinosus-gracilis autograft initially and then Patella-tendon after 2 nd tear. 3 weeks post-op patient started an eccentric exercise program for 31 wks Quad strength increased 28% while protecting the repair no anterior shear force 12 weeks after the repair Eccentric Exercises Preventing Muscle Loss & Injury Sarcopena loss of muscle with aging Muscle tendon Injuries Increased stiffness of tendon greater force to failure and improved ability to absorb energy at the musculo-tendinous junction Osteopena greater loads to bone with higher muscle forces/increased bone mass Reduced Falls in Elderly Increased muscle strength of the hip muscles 19

20 Eccentric Loading to Hamstring Strains Eccentric loading of the hamstrings is performed in the OKC Non wt bearing low velocity eccentric loading exercises Stiff leg dead lifts Nordic hamstring exercise Eccentric backward steps Eccentric forward pulls Eccentric Lunge drops - forward flexion with wt ball Eccentric loading more effective greater changes in neural activation and hypertrophy The Role & Implication of Eccentric training in athletic rehab tendinopathy hamstring strains & ACL reconstruction Lorenz D & Reiman M Internat J Sports PT March 2011 Eccentric forward pulls Forward flexion with wt ball Nordic hamstring exercise Eccentric backward steps Stiff leg dead lifts 20

21 Eccentric Loading to Hamstrings Ballistic Training - Explosive Weight Training - Eccentric Loading Method to develop explosiveness. The athlete accelerates and releases the weight into "free space." Common ballistic training exercises are; bench throws, jump squats, cleans, snatches, and push presses. Ballistic training forces the athlete's body to recruit and trigger fast twitch muscle fibers. Slow return Eccentric loading Ballistic training requires the central nervous system to coordinate and produce the greatest amount of force in the shortest time possible. Eccentric Loading to control the fall - weight excessive force to the muscle and tendon 21

22 Explosive Weight training The power phase of training that combines speed of movement with strength Ballistic The resistance can be lowered to 40-80% 1RM The movement is explosive feet are not required to leaving the platform The hands move away from bar in a bench press Optimal Load for Increasing Muscle Power During Explosive Resistance Training in Older Adults Nathan J. de Vos, Journal of Gerontology: MEDICAL SCIENCES Copyright 2005 by The Gerontological Society of America,2005, Vol. 60A, No. 5, 1RM, peak muscle power (W) was assessed at 10 relative intensities (20%, 40%, 50%, 55%,60%, 65%, 70%, 75%, 80%, and 85% 1RM) 3 experimental groups performed explosive resistance training at three intensities = 20%, 50%, or 80% of their 1RM. Trained 2 days/wk - 8 or 12 weeks using analogue Keiser pneumatic resistance-training machines high-intensity explosive resistance training presents the best strategy for simultaneous improvements in whole-body peak power, strength, and local muscular endurance in healthy older adults 22

23 Plyometric training Stretch Reflex or Myotactic Intrafusal fibers / muscle spindle responds to the rate at which the muscle is stretched Stronger muscle contraction to reduce the stretch Stretch shortening cycle rapid deceleration followed by an immediate rapid acceleration Neuromuscular Training Muscle Spindle Plyometrics Prerequisites Strength base Power Squat 60 % body wt. Normal hip strength One leg half squat balance & quad strength Stork balance test Eyes open / closed Good Quad strength MMT No patella femoral pain / poor alignment Good landing surface/shoes No acute injuries to the foot or ankle 23

24 Types of Plyometrics Natural Plyometrics hopping jumping Depth Jumping Only for specific athletes 220lbs no higher than 18 inches Low intensity Skipping drills, 8 inch cone hops Lateral bounding Shuttle 2000 MVP Vertamax Explosive jump landing mechanics Plyometric Training in Female Athletes Decreased impact forces and increased hamstring torque AJSM 1996 Hewett, Stroupe, Nance, Noyes Teaching neuromuscular control of the LE during landing and to increase vertical jump Results After training peak landing forces dec.22% and knee add & abd moments dec. 50% Hamstring power inc. 44% Peak torque ratio hams/quad inc. 13% 24

25 Plyometric Training hours recovery 2x per week seconds per exercise seconds rest Plyometrics 25

26 Plyometric Drills Sports Specific Summary Eccentric Exercises and Neuromuscular Training in Rehabilitation of the Athlete Keys Points Strengthening Tendons Protective Effect on Muscle Treatment for Tendinopathy Muscle Strengthening Ballistic Exercise Plyometrics = Neuromuscula Training and Eccentric Loading 26