Retraining High Level Mobility Following Brain Injury

Dimensions of Mobility

  • High-level mobility refers to individuals who can walk independently but struggle with activities they performed before their injury.
  • It is crucial for returning to work, sports, social activities, and hobbies.
  • Traditional rehab focuses on basic mobility (transfers, walking), while high-level mobility training advances a person's mobility capacity.

Patient Goals vs. Rehab Service Provision

  • Patients often have higher-level goals (e.g., playing soccer) compared to typical rehab goals.
  • Some patients can achieve significant improvements, even returning to sports and pre-injury activities after considerable time and effort.

Resources and Frameworks

  • American College of Sports Medicine guidelines for resistance training: Provides evidence-based principles for strength training, applicable to neurological conditions.
  • Framework for biomechanics-driven exercise prescription: Addresses the issue of strength improvements not always translating to better walking ability.
  • Shaki's paper on running: Discusses how the body adapts across different running speeds (power, cadence, stride length).

Mobility Continuum

  • Unidimensional view: Focuses solely on physical capacity, progressing from bed mobility to running.
  • Multidimensional view: Considers cognitive, behavioral, and emotional aspects, as well as environmental factors (crossing roads, different surfaces).

High-Level Mobility Assessment Tool (HIMAT)

  • Developed to quantify high-level mobility, enabling benchmarking of outcomes.
  • Addresses the ceiling effects of typical measures like walking speed and the six-minute walk test.
  • Hierarchy: Provides a progression of tasks from walking to running, indicating the relative difficulty of each.
  • Prioritization: Guides treatment and goal setting by identifying achievable steps toward high-level mobility goals.
  • Example: Stair ascent/descent is more difficult than walking but less difficult than running.

Importance of High-Level Mobility

  • Running is essential for various daily activities (e.g., catching a bus) and social participation.
  • People who cannot run have significantly impaired mobility, walking slower than the general population.
  • Running enables fitness maintenance and access to social, leisure, and sporting activities.
  • High-level mobility is associated with improved self-esteem, emotional well-being, participation, and overall quality of life.

Brain Injury Recovery

  • Significant improvements in mobility can occur years after a brain injury.
  • The ability to run is a major milestone in physical capacity.
  • Most brain injuries result from road trauma, affecting primarily young males.

High-Level Mobility and Return to Work

  • A study found that working-age stroke survivors who could run a few steps were three times more likely to return to work.

Benchmarking and Measuring High-Level Mobility

  • Most patients regain the ability to walk after brain injury, but many cannot run or jump.
  • Measuring and reporting high-level mobility helps benchmark outcomes and identify areas for improvement.

Task Specificity in Resistance Training

  • Task specificity: Tailoring exercises to the specific demands of the desired activity (running, swimming, cycling) by considering:
    • Role of the muscle.
    • Type of contraction (concentric, eccentric, isometric).
    • Speed of contraction.
    • Range of motion.
    • Muscle groups involved.
    • Energy systems used.
    • Intensity and volume.

Cadence and Stride Length

  • Running speed is determined by cadence (leg turnover rate) and stride length.
  • Patients often have lower cadence and unequal step length.
  • Training focuses on manipulating cadence and stride length to improve speed.

Changes When Transitioning From Walking to Running

  • Flight phase: Running introduces a flight phase (no ground contact), which is inherently unstable.
  • Stride length and frequency: Running involves greater stride length and frequency compared to walking.
  • Swing phase: A greater proportion of the running cycle is spent in the swing phase.
  • Trunk stability: A stable trunk is crucial for running, serving as the base of support for arm and leg movements.

Spatial Temporal Parameters

  • Optimal stride length: Everyone has an optimal stride length.
  • Cadence: Faster leg movement increases running speed; training aims to improve leg turnover rate.

Biomechanics of Walking and Running

  • Hip: Similar hip biomechanics in walking and running; hip flexion is 40 degrees at initial contact.
  • Knee: Similar flexion-extension patterns in walking and running; running involves twice the range of motion.
  • Ankle: Dorsiflexion is more important for clearance in walking; running requires less dorsiflexion due to increased hip and knee flexion.
  • Pelvic Rotation: Pelvic rotation is reduced in running compared to walking.

Angular Velocities

  • As walking speed increases, the range of ankle joint motion changes, and joints must move more quickly.
  • Muscles must contract faster, necessitating fast, ballistic, and plyometric exercises.

Power Events

  • Hip extensors: Accelerate the body over the foot at initial contact.
  • Plantar flexors (calf): Generate about 60% of the power for forward propulsion during push-off.
  • Hip flexors: Assist in swinging the leg through after push-off.
  • Role of Knee: The knee primarily absorbs power during walking.

Running Program

  • Participants: Individuals who can walk independently and aim to improve mobility.
  • Advanced Skills: Focuses on teaching advanced gait skills and pre-running exercises.
  • Flight Phase: Emphasis on safely introducing the flight phase.
  • Task Breakdown: Involves breaking down tasks into manageable components (e.g., tennis stroke, running) and training them separately before integrating them.
  • Agility Drills: Considers the demands of the specific sport or activity.
  • Process of Rehab: Observe, analyze, treat (reassess); the five attributes are:
    • Stability in stance.
    • Adequate clearance in swing.
    • Adequate step length.
    • Appropriate prepositioning of the foot in swing phase.
    • Energy efficiency and smooth transitions.

Factors Affecting Gait and Running

  • Five contributing impairments:
    • Strength.
    • Balance.
    • Contracture.
    • Spasticity.
    • Motor control.

Major Influences

  • Spasticity:
    • Not as important as originally thought.
  • Balance:
    • Balance is a challenging concept due to the change with an unchanging base of support, and a rapid and ever-changing one within running and walking.
  • Strength:
    • Strength and Power are key! Ankle Strength and Motor Skill are most important

Ankle and Muscle Factors

  • Ankle plantar flexors are the most important muscle group for forward propulsion.
  • Hip extensors and flexors also contribute significantly.
  • Quadriceps are important for stance phase.
  • Dorsiflexors are important for clearance in swing phase.

Problem of Translation

  • RCTs aimed at improving walking speed often target the quadriceps and hamstrings instead of the primary muscles for forward propulsion:
    • Calf.
    • Hip Flexors.
    • Hip Extensors.

Exercise Prescription and the Calf

  • Muscle Contraction, Action, and Reaction:
    • Isometric.
    • Energy stored in the contraction is released in the Achilles Tendon.
  • Calf raises: A common exercise that is slow and doesn't utilize the normal tendon elasticity
  • Leg sled, hopping, and/or Pilates Reformer. On a sled, changing the inclination changes the difficulty. On the reformer, you change the springs and resistance.

Leg Sled and Calf Raises Comparisons

  • Both are loading about 50% of body weight.
  • Both are demanding.
  • The leg sled must be done quickly in order to utilize normal tendon elasticity as well as energy storage and release.

Hip Exercise

  • Adrian's Claw: Cycle of light hip knee flexion and extension.

The Leg Cycle: Stride Length vs. Stride Frequency

  • The increase of speed as a result of stride length is unsafe for patients
  • Train the stride frequency first, then increase the length.

Hip and Trunk Control Connection

  • If a person has not experienced a strong flexor contraction, the trunk comes down toward the thigh rather than the thigh towards the trunk, creating imbalance.
  • Focus on Core Stability, the pelvis and trunk must remain still for a stable exercise.

Goal Recommendations

  • Many people have goals that involve tasks more advanced that just everyday walking! The running group is not exclusive for athletes, it's for anyone.
  • When it comes to outcome measurements, there's no "one size fits all". Scales must change as the patient does.
  • Be specific of the task and what they muscles will do during exercise.
  • Address and be clear with yourself about your patient goals."