General Principles of Exercise Rehabilitation

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Introduction

In order for clinicians to design an effective rehabilitation programme, they need to understand what the specific performance needs of the athlete or individual are. What are the athlete's goals, but also what is their current status? Identifying an athlete's current status will also identify the athlete's current constraints, and most often these constraints are around tissue injury. Implementation of the rehabilitation programme can only start if these factors are in place. The rehabilitation plan is made up out of a loading plan with a clear set of intervention intents. This results in adaptations that lead the athlete from their current status to their performance goals. An important consideration is monitoring and reviewing the interventions and also monitoring against the intended outcome.

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Performance Backward Thinking

• Performing a performance needs analysis with the athlete
  • What is the athlete's performance goal or end goal?
  • What is required to reach this goal?
  • What physical qualities underpin these?
  • What are the current capabilities?
  • What are the barriers and facilitators?

Components of a Performance Needs Analysis

Consider the following in an activity-specific needs analysis:

• Sport, role, position
  • What is the athlete’s role within the activity or sport
• Performance duration
  • Total duration of the athlete’s whole performance
  • What is the duration and frequency of training sessions?
• Activity duration
  • Continuous activity or does it require bursts of varying intensity and duration
• Activities
  • What is involved?
    • Jumping, landing, sprinting, change of direction, kicking, throwing, lifting, carrying?
• Impact sport/Collision sport/Contact sport
• Distances covered and directions moved in
• Endurance and capacity-based requirements
• Strength requirements
• Predominant muscle groups
• Predominant muscle actions
• Flexibility and range of movement demands
• Motor skill requirements

A Paradigm for Needs Analysis and Rehabilitation

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• Performance requirements can include level of strength, level of mobility, level of endurance, coordination tasks
• With an injury, the current status of the injured tissue as well as the athlete’s holistic status needs to be assessed.
  • Reliable and sensitive assessments are necessary to assess the current tissue status
    • What can the injured tissue tolerate at this moment in time?
    • What can the individual do in relation to the injured tissue at this current time with injury?
    • Consider dichotomised versus graded assessment approaches
      • Dichotomised assessment:
        • "Specific structure is painful, therefor it is injured"
        • Simple test with a yes or no answer or yes the structure is injured or no, the structure is not injured.
      • Graded assessment
        • Graded exposure of the tissue to load to see how much load the injured tissue can tolerate.
    • The assumption is often that an acute muscle/ligament/tendon injury will have zero load tolerance when the structure is injured, but often these injured structures can still tolerate a level of load even if it is very little.
      • Examples:
        • If an injured tendon can only tolerate low repetitions of body weight load, then activities such as walking can be restricted, or the relative load reduced by utilising walking aids. However, if the tendon only becomes painful or irritated after running for 10 km, it would be unsuitable to restrict the athlete from running altogether as this will most likely lead to tissue atrophy.
        • If an athlete can lift a 5 kg weight without pain or symptoms, then this would be the starting loading point.
      • Muscle Testing examples:
        • Muscle or tendon: test for the ability to tolerate load with an isometric make-test in mid-range.
        • If the athlete passes the test, then a break-test can be performed where the tissue is eccentrically loaded.
        • Following that, the muscle can be tested in outer range or elongated position, and so forth.
        • In this manner, the tissue load is determined through a graded assessment and a clearer understanding is achieved of the current status of the injured tissue.
      • The level of load an injured tissue can tolerate needs to be clearly identified
        • Note that significant muscle atrophy can occur within 5 -14 days of inactivity. It is, therefore, crucial to determine the minimum activity an injured athlete can perform to reduce the occurrence of atrophy due to underactivity.

Principles of Rehabilitation

Where to Start?

• Identify the start point
• Establish a stable baseline
  • Once the gaps have been identified and a starting point for loading has been identified, that can be seen as the establishment of a stable baseline. The starting point is not always at zero (i.e. no strength or no flexibility) and therefor a graded approach in assessing the tissue tolerance level is key.
  • Consider the load deformation curve
    • refresh your memory here:
    • A certain amount of micro failure is allowed when loading the tissue as this brings on physiological changes, which leads to tissue adaptation, and this strengthens the tissue.
    • If we consider the load-deformation curve and sub-optimally load tissue (loading on the left side to the micro failure zone, this will lead to tissue atrophy and the tissue will weaken to the level of the loads applied.
    • Similarly, if the tissue is overloaded (loading to the right side of the micro failure zone, this can lead to irreparable damage
    • Therefore, it is imperative to apply the maximum load the specific tissue can tolerate.

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Underpinning Theories

• Mechanotransduction = shifting of mechanical energy into physiological energy.
  • Read more here: Mechanotransduction Hypothesis
• Physical Stress Theory - add graphic
  • According to Mueller and Maluf, biological tissues adapt to changes in the levels of applied stress. Maintaining tissue tolerance is essential to prevent atrophy, whereas overloading results in hypertrophy. Excessively high levels of stress lead to tissue injury and potential permanent damage. The magnitude, time, and direction of stress application determine the overall level of exposure to physical stress. Injury may occur due to a high-magnitude stress applied for a brief period, a low-magnitude stress applied for a long duration, and/or a moderate-magnitude stress applied to the tissue many times.
• Principle of Specificity = the body adapts to the loads which are applied to it.
  • Read more here: The Basic Principles in Exercise Physiology
  • Tissue requires loads in specific ways
    • Bone
      • maximal adaption from relatively low exposures ("bone gets bored")
      • 40 - 60 repetitions to maximise adaptation
    • Tendon
      • stretch-shortening or plyometric tasks to transfer energy
      • isometric forces - transfer force across a joint to generate joint movement
      • Read more: Tendon Load and Capacity
    • Muscle
      • responds to the nature of the load
      • responds to the range that load is applied in
      • specific velocities of muscle contraction (Olympic sprinter vs Older person walking to the shops)

Key Issues when Reloading Injured Tissues

• Key issues to remember when reloading injured tissues
• Understand what the stable baseline load is and at what level loading should start at
• What forces stress the injured structure?
• Which forces and loads do not stress the injured structure?
• Ligaments - direction and magnitude of injurious force need to be defined
• Muscle and tendon - nature of contraction load, force velocity and length-tension relationship implications should be defined
• Articular surface - define the direction and magnitude of injurious forces and the impact of malalignment

Monitoring Impact of Load

It is important to know when to proceed with gradual stress and when to take a step back. There are multiple indicators of excess or less load:

• Increased swelling of the training muscles indicates inflammation-overload. Circumferential measures: to be taken after the activity, in the morning and in the evening. Ideally swelling should not increase between days. If it was increased after training it should decrease by the evening, if it is still swollen by the next morning then the training load should be decreased.
• Pain: Visual Analogue Scale (VAS) 0-10, rate the score to a specific movement or exercise. Any change in score the day after training >1 that does not reduce by the evening may indicate overload
• Stiffness: especially in the morning, is a good mark of inflammation. Link the stiffness to a specific task or movement for e.g. simply ask the patient if they find difficulties doing a simple full squat in the morning.
• Muscle contractility or inhibition is influenced by pain and swelling. Monitor muscle contraction force.
• Global loads: technological applications and trackers could be helpful in giving a start point to build up a gradual progressive rehabilitation program without overloading or deloading.

Progressing Load

• Progressively expose to load at tissue and system level
• Maximum tolerated loads necessary to generate supraphysiological stress and low level of micro failure to create adaptation
• Allow for sufficient recovery time to allow for adaptation
• Application of the appropriate load to drive the required adaptation
  • Specific Adaptation to Imposed Demand (SAID) principle
    • Adaptations produced by the training are highly specific to the nature of the stimulus or overload applied
    • SAID applies to all the systems of the body
    • The adaptations are specific to strength, power, endurance, functional activity, joint angle, sequence of muscle activations, energy systems and virtually all other variables present

Key Rehabilitation Areas

Regaining Maximum Force and Force Generation

• Maximum force
  • Overcome muscle inhibition
    • muscle stimulation at the same time as contracting the muscle to superimpose the contraction
    • use crosstalk or effort from the other limb to generate neural activity in injured limb
    • whole body or local vibration
    • relieve pain
    • work in mid-range initially to generate strongest contraction
  • Repetition maximums
    • The repetition continuum or strength-endurance continuum is usually used to prescribe specific loading recommendations.
    • Muscle strength - low repetitions with heavy loads: 1 - 5 repetitions per set with 80% - 100% of 1 -repetition max (1RM)
    • Muscle hypertrophy – moderate repetitions with moderate loads: 8 - 12 repetitions per set with 60% - 80% of 1RM
    • Muscle endurance – high repetitions with light loads: 15 + repetitions per set with loads below 60% of 1RM
    • Read more: Loading Recommendations for Muscle Strength, Hypertrophy, and Local Endurance: A Re-Examination of the Repetition Continuum
• Force generation
  • Force velocity - slow contraction vs rapid generation of force

Regaining Movement Skill

Teaching the movement involves various levels of learning:

• Acquisition/Cognitive stage: deconstructing the function onto simple movements with repetitions.
• Retention/Associative stage: recalling and delivering the task after a period of not practicing the task.
• Transfer/ Autonomous stage: the ability to carry out a task without paying attention to tactics. Ideally, we want to deliver our patients to this stage where they can perform a similar, but different task than originally learned in the acquisition stage.

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Instructing patients depends on the stage of learning. In the first stage, closed skill is used to eliminate all external influences and drives the focus internally (Intrinsic focused cues) by asking patient to reflect on the purpose and the mechanism of a simple movement e.g. single leg squat. Repetitions in this stage aids cognition and acquisition. In Retention and Transfer stages, training should be external or goal focused. For example, asking patient to move towards a certain target, or doing a task while keeping trunk ahead of knees. The ultimate aim of motor skill learning is to transfer the skill to performance in sport or activities of daily living. The patient needs to move from closed skill tasks (same movement tasks in stable predictable environments) to open skill where tasks/movements are unplanned.

Feedback during motor learning:[4]

Feedback can be either intrinsic or extrinsic. Intrinsic feedback - seen as the knowledge of performance but in can be limiting to learning when in extreme. Extrinsic (augmented) feedback can be from visual demonstrations, using a mirror, verbal instructions or guidance through touching.

Verbal feedback aims at giving extra information on the knowledge of performance and the results of the task/movement

Find out from the patient what style of feedback works best for them

Feedback can also be given through open questions allowing the patient to actively problem solve regarding the task performance. It should not only just provide them with information overload but should challenge the patient's believes about their skill performance

Timing feedback is also another important element.

Constant feedback doesn't allow the patient to reflect and learn. Feedback during the performance helps with the immediate prevention of a problem but research shows that it can be detrimental for motor skill learning because the patient becomes dependent on the feedback

Instead, feedback should be given at the end of the training session or either in extreme good or bad performance. Keep in mind that if feedback is only delivered post training the patient may become passive in problem solving

Reduce feedback as training progresses

Summary feedback can be given after the patient completed a number of attempts instead of after individual attempts

The rehabilitation then should develop complexity to mimic the reality of patient's occupation or functional aspirations.

Random Skill training can be acquired in this stage, by training patient to deliver function on various surfaces, with different external loads and to react to external stimuli.

Key Take Home Messages

• Understand the performance requirements
• Identify what load the tissue (and individual) can currently tolerate
• Fill the gap in the performance deficits
• Clearly define the purpose of an exercise
  • Measure the exercise's impact against that purpose
• Always apply the maximum loads the tissue (and individual) can tolerate
• Assess the impact of loading at all stages