GW BGZ 2024 Case 8 - Fit, fitter, fittest: family van Deursen goes active

What is physical fitness?

Physical fitness is the ability to perform daily activities efficiently without excessive fatigue and with enough energy for leisure and emergencies.

It includes:

• Health-related fitness

• Performance-related fitness

Physical fitness differs from:

• Physical activity = any movement increasing energy expenditure

• Exercise = planned physical activity

What are the health-related fitness components?

Health-related fitness focuses on overall health, daily functioning, and disease prevention:

• Cardiorespiratory Endurance

  • Ability of the heart and lungs to supply oxygen during prolonged activity

• Body Composition

  • Ratio of fat mass to lean mass

• Muscular Strength

  • Maximum force a muscle or muscle group can produce

  • Very slow lift

• Flexibility

  • Range of motion at joints

• Muscular endurance

  • The ability of muscles to perform repeated contractions over time

What are the performance-related fitness components?

Performance-related fitness focuses on athletic ability and skill performance:

• Isometric Strength

  • Ability to exert force without movement

• Power

  • Ability to generate force quickly (strength + speed)

• Speed / Agility

  • Speed: rapid movement

  • Agility: quick direction changes

• Balance

  • Ability to maintain stability

• Arm–Eye Coordination

  • Ability to synchronize visual input with movement

• Reaction time

  • How quickly you respond to a stimulus

What are examples of exercises for health-related fitness components?

• Cardiorespiratory Endurance

  • Running

  • Cycling

  • Swimming

  • Brisk walking

  • Rowing

• Body Composition

  • Circuit training

  • Running + healthy nutrition

  • Resistance training

  • HIIT workouts

• Muscular Strength

  • Heavy squats

  • Deadlifts

  • Bench press

  • Leg press

  • Very slow heavy lifts

• Flexibility

  • Stretching routines

  • Yoga

  • Pilates

  • Dynamic stretches

  • Hamstring stretches

• Muscular Endurance

  • Push-ups

  • Sit-ups

  • Planks

  • Bodyweight squats

  • Light-weight high-repetition training

What are examples of exercises for performance-related fitness components?

• Isometric Strength

  • Wall sit

  • Plank hold

  • Isometric squat hold

  • Static lunge hold

• Power

  • Box jumps

  • Sprint starts

  • Olympic lifts

  • Medicine ball throws

  • Jump squats

• Speed / Agility

  • Sprint drills

  • Shuttle runs

  • Ladder drills

  • Cone drills

  • Zig-zag running

• Balance

  • Single-leg stands

  • Balance board exercises

  • Yoga poses

  • Bosu-ball training

• Arm–Eye Coordination

  • Catching drills

  • Tennis

  • Table tennis

  • Basketball passing drills

• Reaction Time

  • Reaction ball drills

  • Sprint start practice

  • Goalkeeper drills

  • Partner clap/catch games

Why and how is physical fitness measured?

To assess:

• Health

• Performance

• Functional ability

• Disease risk

• Rehabilitation progress

Different tests measure different fitness components.

The selection of tests depends on:

• The component being evaluated

• The purpose of testing (health screening, athletic performance, rehabilitation, epidemiology)

• The population (children, adults, elderly, athletes, patients)

• Validity, reliability, feasibility, and safety of the test

Field tests are practical, low-cost methods used in schools, communities, and large populations. Important qualities of these tests are objectivity, reliability, validity, and standardization. Big groups

Laboratory tests are conducted in a controlled environment, mostly within a lab, where conditions can be monitored and standardized. They often use specialized equipment for higher precision. Little groups

How can you measure body composition?

• BMI

• Skinfold thickness testing

• Waist circumference and WHR

• BIA

• DEXA

• Hydrostatic weighing

What is BMI?

BMI estimates body fat using height and weight.

Formula:

BMI=Body Mass (kg)/Height2(m2)

Categories:

• <18.5 = underweight

• 18.5–24.9 = normal

• 25–29.9 = overweight

• ≥30 = obesity

  The values are different for children.

What is skinfold thickness testing?

Measures subcutaneous fat using calipers.

Common measurement sites

• Triceps

• Subscapular

• Suprailiac

• Abdomen

• Thigh

• Chest

• Midaxillary

Principle

Subcutaneous fat correlates with total body fat.

What is waist circumference and WHR?

Measures abdominal obesity and cardiometabolic risk.

WHR formula:

WHR=Waist Circumference/Hip Circumference

Interpretation

Higher values indicate greater abdominal fat distribution and increased health risk.

Common risk cutoffs:

• Men: WHR > 0.90

• Women: WHR > 0.85

What is Bioelectrical Impedance Analysis (BIA)?

BIA estimates body fat using electrical conductivity.

Lean tissue conducts electricity better than fat.

Bioelectrical Impedance Analysis (BIA) is a quick, noninvasive method used to estimate body composition. It works by sending a safe, imperceptible electrical current through the body.

What is DEXA?

Golden standard.

A DEXA (Dual-Energy X-ray Absorptiometry) body composition scan is a quick, non-invasive imaging test that accurately measures your exact ratio of fat, lean muscle and bone density.

DEXA measures:

• Fat mass

• Lean mass

• Bone density

What is hydrostatic weighing?

Based on the fact that a person with more body fat will weigh less underwater because fat is less dense than water, while muscle and bone are denser and sink more.

How It Works

1. The person is weighed on land.

2. They are then submerged in water and weighed again while exhaling as much air as possible.

3. The difference between land weight and underwater weight determines body volume.

4. Body density is calculated: Body Density=Body Mass/Body Volume

5. Body fat percentage is estimated using equations such as the Siri equation: %Body Fat=(495/Body Density)−450

How can you measure cardiorespiratory fitness?

• CPET

• Åstrand Test

• Borg RPE scale

• Cooper 12-minute run test

• Shuttle test

• 6-minute walk test

• 3-minute step test

• 1.5 mile walk test

• Equation

What is VO2max and the Fick equation?

VO₂max is the maximal amount of oxygen consumed during intense exercise.

CO = VO2/CaO2-CvO2

VO2= Q×(a−vO2 difference)VO_2=Q\times(a-vO_2\ difference)VO2=Q×(a−vO2 difference)

Where:

• CO: Cardiac Output (L/min).

• VO2: Oxygen consumption/uptake (mL/min). Often estimated using a metabolic cart or by multiplying (125 mL/min/m^2) by body surface area.

• CaO2: Oxygen content of arterial blood (mL of O2) per dL of blood).

• CvO2: Oxygen content of mixed venous blood (mL of O2 per dL of blood).

VO₂max reflects integrated cardiovascular and muscular function.

What is CPET?

Gold standard assessment.

Measures

• VO₂max

• Ventilation

• Heart rate

• Respiratory exchange ratio

• Anaerobic threshold

Equipment

• Treadmill or cycle ergometer

• Gas analysis system

What is the Åstrand test?

The Åstrand test is a submaximal cycling test used to estimate cardiorespiratory fitness and VO₂max (maximal oxygen uptake).

Purpose

Measures aerobic fitness and the efficiency of the cardiovascular and respiratory systems during exercise.

Procedure

• Participant cycles on a cycle ergometer for 6 minutes

• Constant cadence: usually 50 rpm

• Workload is adjusted according to sex and fitness level

• Heart rate is measured during exercise

• VO₂max is estimated using workload and heart rate tables/nomograms

Physiological principle

Heart rate increases linearly with oxygen consumption during submaximal exercise.

What is the Borg RPE scale?

A subjective scale measuring exercise intensity.

Common scales:

• 6–20

• 0–10

What are the field tests for cardiorespiratory fitness?

Cooper 12-Minute Run

• Distance covered in 12 minutes estimates aerobic fitness.

Shuttle Run / Beep Test

• A running test with increasing pace until exhaustion.

6-minute walk test

• Measures functional aerobic capacity.

• Often used in: elderly, cardiac patients and pulmonary rehabilitation

3-Minute Step Test

• Measures cardiovascular endurance using heart-rate recovery after stepping exercise.

• Step up and down on a bench (usually 12 inches / 30 cm high) → standard cadence: 24 steps/min → duration: 3 minutes

• Immediately after finishing, recovery heart rate is measured for 1 minute

1.5-Mile Walk/Run Test

• Subject walks or runs 1.5 miles as fast as possible

• Total completion time is recorded

• Heart rate may also be measured

Estimation equation

VO2 max=88.02−(0.1656×Body Weight)−(2.76×Time)−(0.0638×Heart Rate)+(3.716×Sex)

Where:

• Weight = kg

• Time = minutes

• Heart rate = bpm

• Sex: male = 1, female = 0

How can you measure muscular strength?

• 1RM

• Isometric dynamometry

• Biodex machine

• Electromyography

• Manual muscle testing

• Grip strength

What is a 1RM test?

Measures maximal weight lifted once.

Examples

• Bench press

• Leg press

• Squat

Advantages

• Gold standard dynamic strength measure

Limitations

• Injury risk

• Requires experience

• Less suitable for elderly or patients

What is isometric dynamometry?

• Measures muscle strength during a static contraction where the joint angle and muscle length remain constant

What is the Biodex machine?

The Biodex Medical Systems machine is an isokinetic dynamometer used to measure muscle strength, power, and endurance.

• Controls movement speed throughout the range of motion

• Measures:

  • Torque

  • Peak force

  • Power

  • Fatigue

• Commonly used for:

  • Knee and shoulder testing

  • Rehabilitation

  • Sports performance

What is electromyography (EMG)?

Electromyography measures electrical activity produced by skeletal muscles.

Types Surface EMG

• Electrodes placed on skin

• Noninvasive

Needle EMG

• Needle electrode inserted into muscle

• More precise but invasive

Uses

• Analyze muscle activation

• Detect neuromuscular disorders

• Study movement patterns

• Evaluate rehabilitation progress

What is manual muscle testing (MMT)?

A clinical method used to assess muscle strength manually against resistance.

Procedure

• Examiner applies resistance while patient contracts muscle

• Strength graded on a scale from 0–5

What is grip strength testing?

Measures hand and forearm strength using a dynamometer.

Used to assess:

• Functional ability

• Frailty

• Overall strength

What is the peak leg extension test?

The peak leg extension test measures maximal lower-body muscular strength, especially quadriceps strength.

Results are expressed in:

• Newton meters (Nm)

Procedure

• Participant performs maximal knee extension against resistance

• A dynamometer measures peak torque/force

Interpretation

Higher Nm = greater muscular strength.

How can you measure muscular endurance?

Simple tests performed outside the laboratory to assess muscular strength and endurance.

Common Examples

• Push-up test

• Sit-up test

• Pull-up test

• Vertical jump test

• Medicine ball throw

Purpose

Evaluate:

• Functional fitness

• Muscular endurance

• Athletic performance

How can you measure flexibility? (field tests)

Sit-and-reach test

Measures flexibility of the:

• Hamstrings

• Lower back

Procedure

• Subject sits with legs extended

• Feet placed against a sit-and-reach box

• Reach forward as far as possible

Shoulder flexibility test

Assesses shoulder joint and upper-body flexibility.

Common Method: Back Scratch Test Procedure

• One hand reaches over the shoulder

• Other hand reaches behind the back upward

• Distance between fingers measured

Interpretation

• Fingers overlapping = good flexibility

• Large gap = reduced shoulder flexibility

Trunk rotation test

Measures rotational flexibility of the trunk and spine.

Procedure

• Subject rotates trunk while seated or standing

• Rotation angle or distance measured

Toe-touch test

Measures hamstring and lower back flexibility.

Procedure

• Subject bends forward attempting to touch toes

• Distance from fingertips to floor recorded

How can you measure flexibility? (laboratory tests)

Goniometry

• Measures joint angle and range of motion using a goniometer.

• Commonly Measured Joints: shoulder, knee, hip, elbow and ankle

Flexometer / Inclinometer

Measures spinal and joint movement angles electronically or mechanically.

Uses

• Spine flexibility

• Trunk motion analysis

Electrogoniometry

Electronic measurement of continuous joint movement during activity.

Features

• Real-time ROM recording

• Dynamic flexibility analysis

What are the different tests for cardiorespiratory fitness?

Test	Type	Measures	Advantages	Limitations
CPET	Laboratory	VO₂max	Gold standard	Expensive
Bruce treadmill test	Laboratory	Aerobic capacity	Diagnostic value	Maximal effort
Cycle ergometer test	Laboratory	VO₂max	Safer	Lower VO₂max
Cooper 12-min run	Field	Endurance	Simple	Requires motivation
Shuttle run/beep test	Field	Aerobic power	Large groups	Coordination required
6-minute walk test	Field	Functional capacity	Clinical use	Submaximal

What are the different tests for body composition?

Test	Measures	Advantages	Limitations
BMI	Weight relative to height	Simple	No fat/muscle distinction
Waist circumference	Abdominal fat	Predicts cardiometabolic risk	Limited detail
Skinfolds	Subcutaneous fat	Cheap	Tester dependent
BIA	Fat percentage	Fast	Hydration sensitive
DEXA	Fat/lean/bone mass	Highly accurate	Expensive
Hydrostatic weighing	Body density	Accurate	Difficult procedure

What are the different tests for muscular strength?

Test	Muscle group	Notes
Handgrip dynamometry	Forearm/hand	Strong predictor of mortality
1RM bench press	Upper body	Maximal dynamic strength
1RM squat/leg press	Lower body	Athletic performance
Leg extension dynamometry	Quadriceps	Used in the case
Isokinetic dynamometry	Multiple	Precise laboratory assessment

What are the different tests for muscular endurance?

Test	Measures
Push-up test	Upper-body endurance
Sit-up/curl-up test	Abdominal endurance
Plank test	Core endurance
Chair stand test	Functional endurance

What are the different tests for flexibility?

Test	Region assessed
Sit-and-reach	Hamstrings/lower back
Shoulder flexibility test	Shoulder girdle
Goniometry	Specific joint ROM
Trunk rotation test	Spinal mobility

How are reference values for fitness tests determined?

Researchers test a large representative population using the same standardized protocol.

They calculate:

• Mean

• Standard deviation

• Percentiles

Results are grouped into categories such as:

• Poor

• Average

• Excellent

For example:

• A VO₂max test performed on a treadmill cannot be directly compared with a cycle ergometer test without accounting for protocol differences.

• Strength measured with different joint angles or equipment may produce different values.

• Flexibility scores vary depending on warm-up and stretching before testing.

→ Calculate back to the most neutral point, where other factors are accounted for. For VO2 max, you can value it as ml/min/kg, where the difference in weight is accounted for

Also, different methods of standardizing can be used:

• Mean: mean score of a group can help standardize individual scores. Comparing individual against the group mean can indicate a relative performance

• Raw score vs scaled score:

  • Raw is the actual measured value before adjustment

  • Scaled is after adjusting the raw score to account for influencing factors, making the comparison more meaningful

For the CPET it is more meaningful to value VO2 max on the lean body mass instead of total body weight → improves a more accurate reflection of aerobic capacity by accounting for muscle mass rather than fat mass.

How does sex influence physical fitness?

Men generally have:

• Larger hearts

• Greater blood volume

• Higher hemoglobin levels

• Larger lungs

This produces:

• Higher stroke volume

• Greater oxygen delivery

• Higher aerobic capacity

Women generally have:

• Smaller heart size

• Lower hemoglobin concentration

• Smaller lungs and airways

• Higher body fat percentage

Effects:

• Lower oxygen-carrying capacity

• Lower absolute VO2 max

• Lower maximal aerobic performance

However:

• Women may have similar relative endurance performance when adjusted for body size

• Often better fatigue resistance in some endurance tasks

How does age influence physical fitness?

Aging reduces most fitness components due to changes in the cardiovascular, respiratory, and muscular systems.

• ↓ VO₂max due to lower HRmax, stroke volume, and cardiac output

• ↓ Lung elasticity and oxygen exchange

• ↓ Lactate clearance and mitochondrial function

• Sarcopenia → loss of muscle mass and strength (starts ~40 yrs)

• ↓ Flexibility from stiffer joints/connective tissue

• ↑ Fat mass and ↓ lean body mass

• ↓ Bone density with aging

Training can slow many of these declines.

Explain the main findings in the fitness case.

• Aerobic fitness declines with age, but Peter (68 yrs) had the same Åstrand score as Paula (45 yrs), suggesting good fitness for his age.

• Men generally showed higher strength and aerobic capacity due to greater muscle mass and stroke volume.

• Women showed higher body fat percentages and better flexibility.

• Blood pressure increased with age; Peter had the highest BP (140/90).

• Flexibility and strength declined in older participants due to aging and sarcopenia.

• Peter maintained relatively good strength and aerobic fitness despite aging, likely from better training status/activity.