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Measuring Fitness

Definition of Fitness - “The ability to carry out daily tasks with vigor and alertness, without undue fatigue, and with ample energy to enjoy leisure-time pursuits and respond to emergencies.” - The ability to perform physical work Components of fitness - Cardiorespiratory Fitness o The combined ability of the circulatory and respiratory systems to supply oxygen to skeletal muscle during physical activity o E.g. VO2max test - Cardiorespiratory Endurance o It is the ability to sustain a workload o E.g. Time to exhaustion at a specific speed - Muscular strength o The ability of the neuromuscular and muscular system to produce force o E.g. 1 rep max - Local Muscular endurance o The ability of the neuromuscular and muscular systems to sustain a workload o Time to exhaustion or number of repetitions with a known resistance - Flexibility o The range of motion available at a joint, can be divided into active and passive ranges of motion - Muscular power output

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o Work done per unit of time o E.g. Vertical jump test Balance o The ability to maintain body static or dynamic equilibrium when perturbated Body Composition o The relative level of muscle, fat, bone and other tissues within the body

The concept of VO2 and VO2 max - Cardiorespiratory fitness is heavily predicated on the body’s ability to uptake oxygen - We term this ‘rate of oxygen uptake’ – or VO2 o Measured in Litres/Min - The maximal rate at which the body can uptake oxygen is known at the maximal oxygen uptake – or VO2 max o Also known as maximal aerobic power - Everybody will have their own VO2 max - When expressing VO2 max, larger people are likely to uptake more oxygen just because they have more tissue, doesn’t mean they are fitter

Absolute versus Relative VO2 max - When expressing VO2max, larger people are likely to uptake more oxygen just because they have more tissue, doesn’t necessarily mean they are fitter - To compare different VO2max magnitudes, we express the result relative to body mass in ml/kg/min

VO2max Versus VO2peak - VO2max is the highest oxygen that is reached with certain criteria (ACSM): o Plateau of oxygen consumption with a subsequent increase in power output o RER > 1.15 o +- 10bpm from predicted MHR o RPE > 17 (Borg) - VO2peak is the highest measured oxygen consumption that doesn’t meet the above criteria

Why are addressing these domains of fitness useful -

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Low cardiorespiratory fitness has been demonstrated to be the greatest predictor of all cause mortality; over hypertension, obesity, diabetes, high cholesterol and smoking status Low levels of muscular strength lead to greater risk of falling and losing independence

Field tests for measuring fitness - Shuttle run test (beep test) o Progressive decrease in time between sounds, it is therefore a maximal test o 20m length and as wide as needed o Little equipment required o Estimated VO2max based on correlation (r= 0.91) - Cooper 12 minute test o Run for distance in 12 minutes o Strong correlation with VO2 max in fit individuals, poor in untrained women and children o However need external motivation and the results from the trained studies indicate pacing strategies and experience will influence the result Field tests for other domains of fitness - Power o Vertical jump height, broad jump distance, medicine ball chest throw - Strength/Muscular endurance o Plank, push up, curl up - Body composition o Skinfolds - Flexibility o Joint ROM, sit and reach test - Balance o Single-leg balance test Estimating of VO2 max (Bruce Test) - Based on how long a subject can last with a set battery of workloads - No gas analysis required - Incremental speed and grade concurrently - VO2max = 2.94 x time x 3.74

Laboratory tests for measuring fitness - Indirect calorimetry o Gold standard for measuring gas exchange and therefore oxygen consumption o Can also measure energy expenditure and metabolism generally o Uses the amount of carbon dioxide expired to back calculate the amount of oxygen consumed o Need expensive equipment and trained technicians - Wingate Anaerobic power test o Cycling as fast as possible for 30 seconds with a load that is equal 7.5% of the subjects body mass o Test of maximal power output and the rate of degradation in power o Disadvantages  Grueling physically and psychologically  Need a special Monark cycle ergometer  Trained technician required

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Costly in both time and money

The Ergometer - An exercise apparatus that quantifies and standardizes physical activity in terms of work and/or power output - Examples: o Treadmill o Cycle ergometer o Ski ergometer o Stair steppers o Rowers Calibration and its importance to accurate measurement - Calibration is a necessary process for accurate data collection - Should be performed on a periodic basis (every month or fortnight) - All measurements have some degree of error, this process quantifies it - What is required for common ergometers? o Treadmill  Belt speed and gradient o Cycle ergometer  Braking forces Calibrating a treadmill - Determine speed and grade percentage error - Measurements

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o Measure the time taken for the treadmill belt to complete 30 revolutions at 5km/hr and convert to km/hr o Measure treadmill belt length to assess belt wear and tear o Use an inclinometer to measure gradient Calculating error o Error (%)= Calculated value on treadmill – displayed value/displayed value

Calculating a Cycle ergometer - Involves dismantling the cycle o Remove the belt from the wheel o Check the pendulum reads 0 o Attach a known weight at the extremity of the belt o If 4kg is not appropriate, adjust the scale or pendulum to read 4kg...