Actual Study guide

🧠 Purpose of Testing

Testing assesses physical function, cardiovascular fitness (VO₂max), muscular strength and endurance, balance, and the ability to perform daily activities (ADLs). It helps clinicians and exercise professionals monitor rehab progress, identify impairments, and develop training or treatment plans.

🔬 Physiological Rationale for Submaximal Testing

Submaximal exercise testing estimates VO₂max based on heart rate response to increasing workloads. The assumption is that HR and VO₂ rise linearly with workload. It allows fitness estimation without pushing subjects to full exhaustion—ideal for clinical or high-risk populations.

📏 Units & Conversions

• VO₂: Liters per minute (L/min) or milliliters per kilogram per minute (mL/kg/min)
  
  

• Weight: 1 lb = 0.4536 kg
  
  

• Height/Distance: 1 foot = 30.48 cm; 1 inch = 2.54 cm
  
  

• Workload: kgm/min or watts
  Accurate conversions are necessary for VO₂ calculations and equipment setup.
  
  

📉 VO₂max Estimation Using Submaximal Data

1. Measure HR at various workloads.
   
   

2. Plot HR (y-axis) vs. Workload (x-axis).
   
   

3. Draw line of best fit.
   
   

4. Extrapolate to 85% of age-predicted HRmax.
   
   

5. Drop down to corresponding workload.
   
   

6. Estimate VO₂max using ACSM metabolic equations or nomograms.
   
   

⚖ Submaximal vs Maximal Testing

• Submaximal: Safer, less physically demanding, lower cost, less accurate. Predicts VO₂max.
  
  

• Maximal: Directly measures VO₂max (via metabolic cart), more accurate but requires specialized equipment and poses higher risk.
  
  

📈 Relationship: Workload – HR – VO₂

As workload increases:

• Heart rate increases linearly.
  
  

• VO₂ increases linearly.
  The slope varies by fitness level. A flatter slope indicates better cardiovascular fitness.
  
  

❤ Estimating HRmax

• Use: HRmax = 220 − age
  
  

• Submax tests typically stop at 85% of HRmax
  
  

  • Example: Age 22 → HRmax = 198 bpm
    
    

  • 85% HRmax = 168 bpm
    
    

📊 Estimating VO₂max with Known HR, Workload, VO₂

Given: workload (e.g. 900 kgm/min), HR (e.g. 140 bpm), and VO₂ (e.g. 2.3 L/min)

1. Plot HR vs. VO₂
   
   

2. Draw best-fit line
   
   

3. Extrapolate to 85% or full HRmax
   
   

4. Project downward to corresponding VO₂
   
   

✅ Advantages & Disadvantages of Submaximal Tests

Advantages:

• Safer for high-risk groups
  
  

• Easier to administer
  
  

• Requires less equipment and training
  
  

Disadvantages:

• Less precise than direct measurement
  
  

• Assumes linearity and accurate HRmax estimation
  
  

• Influenced by factors like caffeine, stress, and medication
  
  

💪 Strength Testing with Biodex

🔁 Types of Muscle Contractions

1. Isometric – Muscle contracts without changing length
   
   

2. Isotonic – Muscle shortens/lengthens under load
   
   

3. Isokinetic – Muscle contracts at a constant speed
   
   

Lab Focus: Isometric contraction using the Biodex Dynamometer

🧬 Muscle Factors That Affect Force Production

• Motor unit recruitment (more = stronger force)
  
  

• Type of fibers (Type II = more force)
  
  

• Initial muscle length (optimal overlap = peak force)
  
  

• Stimulation frequency (summation/tetanus increases force)
  
  

🧪 Why Use Isometric Contraction in Lab

• Safe for all populations
  
  

• Easy to standardize
  
  

• Minimizes joint movement
  
  

• Helps isolate specific muscle groups (e.g. quadriceps at 60° flexion)
  
  

⏱ Why 60–90 Seconds of Rest Between Trials?

• Prevents fatigue
  
  

• Ensures ATP-PC system recovery
  
  

• Ensures consistent maximal effort across sets
  
  

• Ideal: less than 10% variation between trials
  
  

📐 Biodex Output Measures

• Torque (N·m): Rotational force
  
  

• Time to peak torque
  
  

• Graph of force over time
  Used for assessing muscular strength objectively.
  
  

🏥 Clinical Implications of Biodex Results

• Monitor rehab progress
  
  

• Identify asymmetries or deficits
  
  

• Guide return-to-play decisions
  
  

• Track outcomes after injury or surgery
  
  

🩺 Why Biodex is Safer for Orthopedic Patients

• No weights or dynamic movement
  
  

• Low joint/tendon strain
  
  

• Controlled and adjustable positioning
  
  

• Suitable for post-injury populations
  
  

🧍 Functional Assessment

🔄 Purpose of Functional Tests

To evaluate a person’s ability to carry out basic ADLs:

• Standing
  
  

• Walking
  
  

• Toileting
  
  

• Dressing
  
  

• Climbing stairs
  
  

Identifies independence level and fall risk.

🚶 6-Minute Walk Test (6MWT) – Setup & Purpose

• Assesses aerobic capacity & endurance
  
  

• Used in geriatrics, pulmonary rehab, and cardiology
  
  

• Reflects real-world mobility
  
  

Setup:

• Cones 100 ft apart
  
  

• Stopwatch, lap counter, pulse oximeter optional
  
  

📋 6MWT Procedure

1. Measure resting HR
   
   

2. Read instructions clearly
   
   

3. Patient walks back and forth for 6 minutes
   
   

4. Clinician follows for safety
   
   

5. Record:
   
   

   • Total distance
     
     

   • HR post-walk
     
     

   • Oxygen saturation (if used)
     
     

👍👎 6MWT Pros & Cons

Pros:

• Easy to perform
  
  

• Reflects ADL capacity
  
  

• No special equipment
  
  

Cons:

• Not a direct VO₂ measure
  
  

• Requires flat space
  
  

• Influenced by motivation/pacing
  
  

🧍‍♀ Standing Physical Performance Battery (SPPB)

The SPPB is a validated clinical tool used to assess lower-body function, balance, mobility, and risk of disability or falls—especially in older adults. It consists of three subtests:

🔹 1. Chair Stands Test – Assessment of Lower-Limb Strength

Purpose: Measures functional leg strength and power—important for ADLs like standing from a toilet or getting out of a car.

Procedure:

• Have the subject sit in a chair with their arms crossed over their chest.
  
  

• Feet should be flat on the floor, back straight.
  
  

• Instruct the subject to stand all the way up and sit all the way down, 5 times as quickly as possible without using their arms.
  
  

• Start timing when you say “Go.”
  
  

• Stop the timer when the subject completes the 5th stand (i.e., standing upright at the end).
  
  

🔹 2. Balance Battery – Assessment of Static Balance

Purpose: Detects balance deficits and fall risk. The test is progressive—participants must successfully hold easier positions before advancing.

Setup:

• Use a wall or sturdy chair nearby for safety.
  
  

• Have the subject remove shoes if necessary.
  
  

🦶 Step-by-step Instructions:

a. Side-by-Side Stance:

• Feet together (heels and toes touching).
  
  

• Subject can use wall or chair to get into position but must let go before timing starts.
  
  

• Goal: Hold for 10 seconds.
  
  

• Allow 2 attempts.
  
  

• If unable to hold for 10 seconds, STOP the balance test.
  
  

b. Semi-Tandem Stance:

• One foot’s heel touches the big toe of the other (either foot in front).
  
  

• Begin timing once subject lets go of support.
  
  

• Conditions for stopping:
  
  

  • Foot movement
    
    

  • Touching support
    
    

  • Unable to continue
    
    

• If unable to hold for 10 seconds, do not proceed to tandem stance.
  
  

c. Tandem Stance:

• Heel of one foot directly in front of the toe of the other (tightrope stance).
  
  

• Hold for up to 10 seconds, max 2 attempts.
  
  

🔹 3. 4-Meter Gait Speed Test – Assessment of Mobility

Purpose: Walking speed is one of the best predictors of functional independence and frailty. Slower speeds are associated with higher fall risk and hospitalization.

Materials Needed:

• Two cones/tape markers
  
  

• Stopwatch
  
  

• Data collection sheet
  
  

• 4-meter measuring tape
  
  

Procedure:

1. Place cones 4 meters apart in a straight hallway.
   
   

2. Instruct the subject to start a few strides behind the first cone and walk “as fast as possible without jogging.”
   
   

3. Start the timer once the subject crosses the first cone.
   
   

4. Stop the timer when they cross the second cone.
   
   

5. Encourage walking through the finish line to avoid early slowing.
   
   

Why start behind and walk through?

• It avoids capturing acceleration/deceleration phases, giving you their true peak walking speed.
  
  

🧾 TOTAL SPPB SCORING

Interpretation:

• 10–12: Good physical function
  
  

• 7–9: Mild limitations
  
  

• 4–6: Moderate risk of disability/falls
  
  

• 0–3: Severe limitation, high fall risk
  
  

🧮 SPPB Scoring

• Each test: 0–4 points
  
  

• Total: 0–12
  
  

• Higher score = better function
  
  

• Lower score = frailty, fall risk, predictor of disability
  
  

🏃 FITT Principle & Training Concepts

📊 FITT Principle

• Frequency: How often (e.g. 3–5x/week)
  
  

• Intensity: %HRmax, RPE, VO₂ reserve
  
  

• Time: Duration (e.g. 30–60 min)
  
  

• Type: Mode of exercise (e.g. walking, cycling)
  
  

⚙ Principles of Aerobic Training

• Overload: Must challenge the system to improve
  
  

• Progression: Gradually increase stimulus
  
  

• Specificity: Gains match the activity performed
  
  

• Reversibility: Use it or lose it
  
  

• Recovery: Critical for adaptation and injury prevention

🧮 Karvonen Method – Target Heart Rate

Formula:

Target HR=(HRmax−HRrest)×%Intensity+HRrest\text{Target HR} = \left( \text{HRmax} - \text{HRrest} \right) \times \% \text{Intensity} + \text{HRrest}

Example:

• HRmax = 198
  
  

• HRrest = 60
  
  

• Intensity = 70%
  
  

=(198−60)×0.70+60=157.6 bpm= (198 - 60) \times 0.70 + 60 = 157.6 bpm