9.1 Basic Principles in Sports Rehabilitation

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Contents

9.1 Basic Principles in Sports Rehabilitation 221 9.1.1 Introduction 221

9.1.2 Cornerstones of Restoration of Proper Musculoskeletal Function 221 9.1.2.1 Lower Limb Alignment 221

9.1.2.2 Joint Kinematics 221

9.1.2.3 Illustrating the Importance of Joint Kinematics:

Weak Point of Current ACL Single-Bundle Surgeries 221 9.1.2.4 Joint Stability 223

9.1.2.5 Proprioception and Neuromuscular Control 223 9.1.2.6 Proper Length–Tension Relationship 224 9.1.2.7 Proper Force Couples 225

9.1.2.8 Management of Concomitant Pain 225

9.1.2.9 Key Concept: the Importance of Early Pain Management 225 9.2 Worked Examples: ACL Recent Advances and Rehabilitation After Acute

Shoulder Dislocation in Sports 226 9.2.1 Introduction 226

9.2.2 Principles of Shoulder Rehabilitation After Acute Shoulder Dislocation 228

9.2.2.1 Introduction 228

9.2.2.2 Control of Pain and Inflammation 228

9.2.2.3 Re-Establish Normal Activation Patterns of Kinetic Chain 228 9.2.2.4 ROM Restoration 228

9.2.2.5 Restoration of Scapulothoracic and Glenohumeral Stabilisers 228 9.2.3 Neuromuscular Co-Ordination Training 229

9.2.4 Sports-Specific Training 229 9.2.5 Cardiovascular Conditioning 230

9.3 Concept of Strength–Endurance Continuum in Training for Professional Athletes 230

9.3.1 Introduction 230

9.3.2 Metabolic Pathway of Endurance Athletes 230

9.3.3 Physiological Adaptations After Prolonged Endurance Training 230 9.3.4 Metabolic Pathway of Athletes Needing “Strength and Speed” 231 9.3.5 Physiological Adaptations to Prolonged Strength Training 231 9.3.6 Argument Against Concurrent Training 231

9.3.7 Argument for Concurrent Training 232

Principles of Sports Rehabilitation

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9.3.8 Use of “Circuit Resistance Training” 232 9.3.9 Some Examples in the Sports Arena 232 9.3.10 Concept of “Strength–Endurance” Continuum 233

9.3.11 Importance of Specificity in Training in Endurance Sports 234 9.3.12 General Conclusions 234

9.3.13 Practical Recommendation for Professional Athletes 234 General Bibliography 235

Selected Bibliography of Journal Articles 235

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9.1 Basic Principles in Sports Rehabilitation

9.1.1 Introduction

n We have already discussed the basic science of healing of soft tissues, and the various physical therapy techniques

n This short chapter serves to highlight the application of the principles discussed in sports rehabilitation

n A separate discussion has been included of the hot topic in sports medicine circles concerning the compatibility of simultaneous endurance and strength training for professional athletes

9.1.2 Cornerstones of Restoration of Proper Musculoskeletal Function

n Proper limb alignment and biomechanics

n Proper joint kinematics, stability and proprioception

n Proper neuromuscular control including sequence of firing (among individual muscles and between different functional groups)

n Proper length–tension relationships

n Proper force couples

n Proper pain management 9.1.2.1 Lower Limb Alignment

n Malalignment of the LL (e.g. bony deformity or malunion, or lever arm dysfunction) can adversely affect the biomechanics not only of the nearby joints, but of the whole kinetic chain and gait. Manage- ment of deformity and malunions was discussed in the companion volume to this book entitled Orthopedic Traumatology, A Resident’s Guide

9.1.2.2 Joint Kinematics

n A very good example is the realisation in recent years that many ACL reconstructed knees may have residual abnormal kinematics as well as rotational instability

9.1.2.3 Illustrating the Importance of Joint Kinematics:

Weak Point of Current ACL Single-Bundle Surgeries

n Normal knee kinematics not restored: most recent in vivo kinematics and high-speed stereo radiographic studies consistently show only antero-posterior stability is restored, but not rotational stability

a 9.1 Basic Principles in Sports Rehabilitation 221

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n This is due to the fact that in normal human knees, the ACL is di- vided into the anteromedial (AM) bundle, which prevents antero-posterior translation, and the posterolateral (PL) bundle, which prevents rotation

n Current single-bundle surgeries mainly reconstruct AM bundle with good results with regard to AP translation as measured by KT-1000, but since the PL bundle is not restored, subtle rotational instability and hence abnormal knee kinematics remain

n Another weakness of current single-bundle surgery is that with time, the bundles tend to stretch out

n There are two common reasons: one is that the athlete may be placing excess demands on his knee; the other reason (which is probably more common) is that proper knee kinematics was not restored 9.1.2.3.1 Consequence of Abnormal Kinematics

n Many patients still feel a sense of rotational instability

n There is a possibility that abnormal knee kinematics may predispose to OA knee (although some cases of post ACL reconstruction OA can be due to other causes like concomitant meniscus injury, cartilage injury, bone bruises, etc.)

9.1.2.3.2 Word of Caution

n The above discussion does not imply that the double-bundle tech- nique has no weak points either; they include:

– No long-term clinical studies, although preliminary postoperative knee kinematics studies are encouraging

– As hamstrings are used in this type of reconstruction, there can always be a chance of graft inadequacy, and may need to resort to allograft with its associated disadvantages

– Technically demanding

– Also, the recent trend is to do early arthroscopy to ensure where both AM and PL bundles are torn. If one is intact (say PL) and it is not stretched out, reconstruction of AM bundle only may be considered, in which case high accuracy of tunnel placement is even more essential

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9.1.2.4 Joint Stability

n Restoration of joint instability is important for the proper working of the kinetic chain as a whole. The relative contribution of soft tissue and bony elements, as well as the dynamic stabilisers involving the muscles, vary between joints – but proprioceptive retraining is always required

n Example: It took years to realise that subtle rotational instability exists in many seemingly stable ACL-reconstructed knees

9.1.2.5 Proprioception and Neuromuscular Control

n Training of proprioception and neuromuscular control was discussed in detail in Chap. 4

n In the setting of ACL injuries, it is generally believed that restoration of appropriate tension of capsuloligamentous structures subsequent to surgical correction (i.e. ACL reconstruction) may directly facilitate the re-innervation potential of damaged articular structure

n In the past, there has been much controversy regarding the use of knee braces in ACL-reconstructed knees, including claims by some that it may improve proprioception; we will take this opportunity to tackle this point

9.1.2.5.1 Role of Braces After ACL Reconstruction

n Mechanics of action of knee braces – besides possible placebo effects, may increase relative knee stiffness even though the maximum laxity frequently remains unchanged

n Advantages of knee braces:

– Possibly increase knee stiffness

– May enhance proprioception – but no study to date has proven this point beyond doubt (subjective stability remains the strongest argument for functional bracing in ACL-deficient or -reconstructed knees)

n Disadvantages:

– May give a false sense of security – Give-way episodes still can occur

– If it does not fit well, it will piston and migrate on the thigh/mal- positioning of the hinges

– Theoretical risk of disconjugate motion between the knee and the brace axes can increase the strain on ACL

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– Under high loading conditions, the ability of brace to control pathological anterior laxity remains in question

– Delays voluntary muscle reaction time and muscular control – Custom-made knee brace may be required in the setting of abnor-

mal limb contour

9.1.2.5.2 Selecting the Ideal Knee Brace

n The ideal knee brace should allow normal rotation and translation to occur, preferably not increase (but decrease) the strain on ACL graft

n Important factors:

– Design – bilateral hinge-post-shell design most rigid; the 4-point fixation brace most effective in controlling anterior tibial translation

– Degree of fit between leg and brace – Any axes mismatch

– Length – longer the brace, the more resistance it provides against anterior tibial displacement (balance between length and patient comfort)

– Some biomechanical studies did show a possible decrease in anterior tibial translation under low loads and/or having some restraint on axial rotation

9.1.2.5.3 Three Key Factors for Overall Brace Performance

n Mechanical feature of the brace – basic design and hinge

n Structure integrity of the design

n Brace limb interaction during loading. (On this point, a fine balance needed since brace–body interface being too rigid may accentuate ef- fect of differences in axes between the knee and the brace)

9.1.2.6 Proper Length–Tension Relationship

n Example: the importance of length–tension relationship is exemplified by the observation that some athletes with ruptured Achilles tendon treated with casting may heal with the tendon lengthened

n This will cause weakened push-off, which may be reflected in a dete- rioration of sports performance, thus illustrating the importance of proper restoration of length–tension relationship in orthopaedic rehabilitation

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9.1.2.7 Proper Force Couples

n Muscles around a joint are frequently designed to work as force couples; thus, under normal circumstances, the tone of agonist and an- tagonists around a joint work together to stabilise the joint

n An example of an area of the body where this principle of force couples needs to be particularly fine tuned and under delicate control are the rotator cuff muscles that help in stabilising the very mobile shoulder and centralise the humeral head in arm elevation

9.1.2.8 Management of Concomitant Pain

n The management of pain is so important that a separate chapter is devoted to pain (Chap. 15)

n Most literature on rehabilitation just mentions comments like “concomitant pain management is needed”, etc. This is an understatement of the effects of pain

9.1.2.9 Key Concept: the Importance of Early Pain Management

n It cannot be over-emphasised that early pain management in the course of rehabilitation is most important, aiming at complete eradi- cation of pain

n Pain, if persistent, will not only limit motion, it will limit flexibility, as is recorded in every standard textbook

n Pain, if persistent, causes prompt muscle wasting, e.g. pain after knee injury can quickly cause quadriceps shutdown and wasting if poorly managed

n Furthermore, if the patient is left with partially treated pain as well as the associated muscle weakness, the body tends to adopt an altered sequence of firing of muscles (Pathophysiology 2005) and rehabilitation of the wasted muscle group will be made even more difficult

n Persistent pain causes persistent spasticity and decreased relaxation of the affected muscle group. We know from our previous discussion that there is a narrow window for optimal sliding of muscle contrac- tile units. Muscles persistently contracted and spastic from pain will affect performance and impair flexibility

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9.2 Worked Examples: ACL Recent Advances

and Rehabilitation After Acute Shoulder Dislocation in Sports

n Management of ACL injury was discussed in the companion volume of this book, including optimisation of surgical techniques in ACL reconstruction

n Some recent advances include:

– The use of surgical navigation in improving the accuracy of tunnel placement is worthy of note (Fig. 9.1)

Fig. 9.1. Surgical navi- gation is now used in some centres to improve accuracy of tunnel placement in ACL reconstruction

Fig. 9.2. Useful adjunc- tive equipment for performing under-water walking and other exercises popular in Scandinavian countries

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– Incorporating the use of water sports in ACL rehabilitation programme (Fig. 9.2), such as underwater walking or running

– The growing need to document ACL outcomes with kinematic data instead of the usual KT-2000 measurements (see Figs. 9.3, 9.4)

a 9.2 Worked Examples 227

Fig. 9.3. Therapist per- forming the KT-1000 testing in a postoperative patient after ACL reconstruction

Fig. 9.4. KT-2000, which has superseded KT-1000, involves testing as in Fig. 9.3 together with objective machine testing with print-outs

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9.2.2 Principles of Shoulder Rehabilitation After Acute Shoulder Dislocation 9.2.2.1 Introduction

n Acute shoulder dislocation is not uncommon in sporting events after rugby or other contact sports

n It is also a common question asked in professional examinations

n The following is a worked example of the use of the principles learned in rehabilitation of a patient after acute shoulder dislocation 9.2.2.2 Control of Pain and Inflammation

n Rest – in the case of shoulder dislocation, immobilise for ~3 weeks

n Pain-relieving modalities, e.g. ice, TENS, ultrasound, microwave dia- thermy

n Drugs, e.g. NSAID

n Soft tissue massage

9.2.2.3 Re-Establish Normal Activation Patterns of Kinetic Chain

n Rationale: the entire kinetic chain should be integrated into the rehabilitation process to minimise overload on the shoulder

n Assess and correct any breakdown and improper sequencing, e.g. poor shoulder and body stance posture, abnormal scapula positions, identify disorders of acromioclavicular joint (ACJ)/sternocostoclavicular joint (SCJ), muscular weakness and strength imbalances of UL/neck/trunk/LL 9.2.2.4 ROM Restoration

n Go gradually from passive, to assisted active, to active exercises

n Avoid movement in the direction that puts stress on the repair (e.g. if Bankart repair was done), or on the healing tissue for the initial peri- od. Usually, soft tissue healing takes at least 6 weeks

n Establishment of full-shoulder ROM is essential, especially for professional athletes who perform overhead throwing

9.2.2.5 Restoration of Scapulothoracic and Glenohumeral Stabilisers

n A stable base for shoulder function is dependent on three main groups of muscles

– The rotator cuff

– Scapulothoracic stabilisers

– Extrinsic muscles of the shoulder complex

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9.2.2.5.1 The Rotator Cuff

n Important for the dynamic stability of the glenohumeral joint through the passive tension of the rotator cuff muscles and their action acting as humeral head depressor and stabiliser by compressing the joint surface and adjusting the tension of the static soft tissue restraints

n Especially important to restore the cuff function in cases of shoulder instability case

9.2.2.5.2 Scapulothoracic Stabilisers

n These consist of: rhomboids, trapezius, levator scapular, serratus anterior, pectoralis minor

n Important in stabilisation of the scapula. Normal scapula kinetics is important to elevate the acromion and avoid impinging the rotator cuff during arm elevation. Also, key role in subsequent sports-specific retraining, e.g. in professional throwers (e.g. scapula retraction during cocking, and protraction upon deceleration in the follow-through phase of throwing), swimmers

9.2.3 Neuromuscular Co-Ordination Training

n In later phase of rehabilitation: need to retrain deficits in proprioception and normal muscle co-ordination of the shoulder to avoid any impairment of functional stability and performance of complex activities especially in the athletic young patient

n Examples:

– Stretch shortening drills to enhance neuromuscular coordination by combining strength with speed of motion

– Proprioceptive neuromuscular facilitation adopts diagonal movement patterns that simulate normal functional planes of motion – can be used in enhancing neuromuscular control of the shoulder girdle by promoting co-contractions and facilitating muscular sy- nergy and kinetic awareness

9.2.4 Sports-Specific Training

n In late rehabilitation, we may need to tailor the rehabilitation process to duplicate sport-specific dynamics and match individual needs

n Analysis of the biomechanical needs of specific sports is highly advis- able. Illustrations of the biomechanical needs of common sports like tennis and the golf swing were discussed in Chap. 5

a 9.2 Worked Examples 229

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9.2.5 Cardiovascular Conditioning

n Total body aerobic conditioning should be initiated as early as possible after injury or surgery if this does not aggravate pain or impair healing

n This minimises effects of disuse and also has positive psychological impact on our patients

9.3 Concept of Strength–Endurance Continuum in Training for Professional Athletes

n There has been much controversy among sports and athletic trainers as regards the compatibility of concomitant endurance vs strength training in high performance professional athletes

n The following discussion attempts to resolve the above controversy 9.3.2 Metabolic Pathway of Endurance Athletes

n Aerobic metabolism (the form used by endurance athletes) uses fat derived from triglycerides stored in muscles and glucose derived from glycogen stores. With endurance training, there is an adaptive increase in the enzymes for oxidation of lipids and relative sparing of glycogen stores

n An example of endurance athlete is a long distance runner 9.3.3 Physiological Adaptations After Prolonged Endurance

Training

n Resting bradycardia (hence more heart rate reserve)

n Increased stroke volume, increased maximum cardiac output – that eases delivery of oxygen and substrates to tissues and quickens the rate of removal of unwanted metabolites from tissues

n Peripheral oxygen delivery is also aided by concomitant increases in total blood volume, red cells and haemoglobin

n Capillary density surrounding the types 1 and 2 muscle fibres also increases

n Increases VO2 maximum by up to 30% with intensive training. Even when the increase in VO2maximum plateaus, endurance performance can sometimes increase further by mechanisms such as increased tol-

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erance to the extent of exercise intensity before the onset of blood lactate accumulation from more effective aerobic mechanism, and/or more efficient removal of lactate from peripheral tissues

9.3.4 Metabolic Pathway of Athletes Needing “Strength and Speed”

n These athletes use anaerobic metabolism with glucose as the major fuel source. This results in lactic acid accumulation and an oxygen debt. A transition to aerobic metabolism occurs as the sporting event’s duration exceeds 2–3 min

n Sprinters are the typical examples of this type of athlete

9.3.5 Physiological Adaptations to Prolonged Strength Training

n In response to resistance and strength training, there is mainly muscle hypertrophy and the muscle cross-sectional area increases of both slow- and fast-twitch muscle fibres depending on the training protocol. Slow-twitch fibres hypertrophy more with high-volume, low-intensity training; fast-twitch fibres hypertrophy more with low volume, high-intensity training

n On a microscopic scale, there is a decrease in “mitochondrial density”

or the number of mitochondria per volume of muscle tissue with increase in muscle mass, even though the number of mitochondria may increase slightly. This change lowers aerobic capacity and is a phe- nomenon known as “mitochondrial dilution” – forms the basis of argument (by some) against concurrent strength and endurance training in professional athletes

9.3.6 Argument Against Concurrent Training

n Loss of aerobic power can occur by the decrease in mitochondrial density as muscle hypertrophy sets in with prolonged resistance training

n Example: this explains why weight lifters for example refrain from endurance training, while do they take part in active strength training.

It has been shown in the literature in the past (Kraemer, J Appl Phys- iol 1995) that a short-term bout of high-intensity endurance exercise inhibits performance in subsequent muscular strength activities

a 9.3 Concept of Strength–Endurance Continuum 231

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9.3.7 Argument for Concurrent Training

n Unlike weight lifters for whom strength training forms the mainstay of their training programme. Other athletes such as sprinters who de- sire a well-rounded conditioning programme incorporating both aerobic and strength training should not be denied this opportunity; the same principle also applies to older athletes (Hurley, Exerc Sports Sci Rev 1998)

9.3.8 Use of “Circuit Resistance Training”

n Newer regimens like “circuit resistance training” that de-emphasise the traditional, very brief intervals of heavy muscle strengthening in standard resistance training protocol are gaining in popularity. This is because this form of training provides a more general conditioning, with demonstrated improvements in body composition, muscle endurance and strength, as well as cardiovascular fitness (Haennel, Can J Sports Sci 1989)

n In addition, circuit resistance training also provides supplementary off-season conditioning, even for sports that demand high levels of strength and power

9.3.9 Some Examples in the Sports Arena

n Track and field: take the example of a runner who has had a hip injury that has lingered for some years, and who runs with a “seated”

style due to his weak hip extensors. A strength training programme employing highly specific exercises designed to re-activate the hip extensors, as well as strengthen them, can make for more efficient and therefore faster running. Thus, strength training can sometimes be of benefit to endurance athletes

n Rowing sports: take the example of the rower with weak low back muscles and poor core stability. Strengthening the weakened back and trunk muscles to improve core stability can correct the weak link and allow optimal connection between force generators and the oar. Again, this is an example of strength training benefiting an endurance athlete

n Perhaps the best example of situations whereby strength training can become important even in endurance sports like the marathon one can think of is as follows. If one looks at the champion of an Olympic marathon and the champion of a wheel-chair marathon race for para-

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athletes, one will make the following observation: many marathon champions have long thin non-muscular limbs. But the champions of wheel-chair races for paraplegics have strong muscular upper bodies (Fig. 9.5), in fact resembling athletes who do bench presses. In this scenario (the wheelchair endurance athlete), muscle strength of the upper body is key. Moreover, the wheelchair racer is depending on a much smaller total volume of muscle to do the work of the marathon race. The total volume of muscle is small enough so that the heart is no longer the limiting factor. In this situation, gaining muscle mass in combination with endurance training results in a more powerful endurance engine. In athletes such as these, strength training (of the upper body) is in fact a necessity in their training

9.3.10 Concept of “Strength–Endurance” Continuum

n This implies that muscle strength and muscle endurance exist on a continuum, with muscle strength being 1 RM and muscle endurance representing the ability to exert a lower force repeatedly over time.

Low numbers of repetitions (6–10 RM) are associated with increases in strength and high numbers (20–100 RM) are associated with increases in endurance. As repetitions increase, there is a transition from strength to endurance – thus the concept of a continuum

a 9.3 Concept of Strength–Endurance Continuum 233

Fig. 9.5. Notice the well-built upper body of this gold medallist winning a marathon for wheel-chair users

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9.3.11 Importance of Specificity in Training in Endurance Sports

n Example: cross-country skiing often requires the use of a lot of muscles simultaneously, making the heart the limiting factor and excess muscle mass wasteful. However, when it comes to double poling, the situation changes and adequacy of the upper body mass and muscular strength becomes very important. Double poling is important in cross-country ski racing. This is a good example of the frequent need for concomitant or concurrent strength and endurance training

n This example also helps us to understand that the above statement should be qualified by the fact that strength training (in endurance athletes) should only be tailored to the particular type of sport, no more and no less

9.3.12 General Conclusions

n Many sporting events involve both endurance and strength, and thus concurrent training may be more helpful than harmful

n However, the above statement does have limitations. At one extreme end of the spectrum, we have weight lifting in which most coaches will still recommend a predominant strength training programme in preparation for competition rather than endurance training. At the other extreme end of the spectrum, we have marathon running in which most coaches will recommend a predominant endurance training protocol in preparation for competition for medals, although an occasional marathon runner with, say, weakness of hip extensors may benefit from some strengthening of these anti-gravity muscles 9.3.13 Practical Recommendation for Professional Athletes

n Category 1: athletes whose sports involve mainly demands of strength and power: such as power lift, high jump, sprinting, shot putts – the main part of their training, especially when the competitive season is drawing near, is still strength training. For particular sports, we may wish to add speed and plyometric training. The role of circuit resis- tant training has been discussed and may be useful, but the author will shy away from its use when anywhere near the competitive season. Aerobic training for fitness can be considered off-season

n Category 2: athletes whose sports involve both anaerobic power and endurance, such as the 200–400-m dash, 100-m swimming. The author recommends incorporating more aerobic as well as strength

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training into the programme. The muscle groups to be strengthened depend on the particular type of sport. Less intensive strength training occurs off-season to prevent the events of de-training, which can occur pretty quickly, as early as 2 weeks of de-training

n Category 3: athletes whose sports entail mainly aerobic endurance involving oxidative phosphorylation pathways; the author recommends mainly endurance training. But early on between seasons, careful as- sessment of the different muscle groups of the athlete is important – the example given above of strengthening the weakened back muscles in an endurance rower has been referred to earlier, among many other examples. A good coach should spot these deficiencies early on and have the weakened muscle group(s) corrected before the competitive season arrives when predominantly endurance training (in the marathon runner, for example) holds the main key to getting the gold medal

General Bibliography

Anderson MK (2005) Foundations of Athletic Training, 3^rd Edition. Lippincott Wil- liams & Wilkins, Philadelphia, USA

Selected Bibliography of Journal Articles

1. Fabian S, Hesse H et al. (2005) Muscular activation patterns of healthy persons and low back pain patients performing a functional capacity evaluation test. Pathophys- iology 12(4):281–287

2. Kraemer WJ, Patton JF et al. (1995) Compatibility of high intensity strength and endurance training on hormonal and skeletal muscle adaptations. J Appl Physiol 78(3):976–989

3. Hurley BF, Hagberg JM (1998) Optimizing health in older persons: aerobic or strength training. Exerc Sports Sci Rev 26:61–89

4. Petersen SR, Haennel RG et al. (1989) The influence of high velocity circuit resistance training on VO₂max and cardiac output. Can J Sport Sci 14(3):158–163

a Selected Bibliography of Journal Articles 235