Week 4 Fitness Appraisal

How do we express CRF values?

L per min: Litres of O2 used by the body each minute

ml/ kg/ min: Ml of O2 used by each kg of body weight each minute

METs; multiples of resting metabolic rate

What is the criteria of choosing an appropriate CRF test?

• Age

• Fitness level

• Known health problems

• Risk of CHD

• Availability of needed equipment and personnel

What are the steps prior to testing?

• Informed consent

• Pre-participation and health screening

  • Referral to a health professional needed?

  • Review history for absolute and relative contraindications

  • Resting cardiovascular tests (BP, HR) and body composition

What are the general indications for stopping an exercise test?

• Angina, systolic BP, excessive rise in BP, shortness of breath, wheezing, leg cramps, claudication, fatigue

• HR and heart rhythm

• Subject communication

• Failure of testing equipment

What are the common measures to examine CRF?

• HR

  • fitness indicator at rest and at submaximal levels

  • Duration

    • 30s or 1 min at rest

    • 10, 15, or 30s during exercise (longer is more accurate)

    • Take for 10 to 15 seconds postexercise.

  • Radial pulse typical

• BP

  • SBP should rise with increasing workloads

  • Diastolic BP remains same or may decrease slightly

  • Proper cuff size and adherence to standard technique are imperative for accurate readings

• RPE

  • Rating of perceived exertion gives subjective information regarding intensity of activity (Borg scale, 0 to 10 relative effort)

What are graded exercise tests (GXT)?

• Tests with incrementally increasing workload

  • Maximal GXT (client stops cause of exhaustion)

  • Submaximal GXT (client stops at 85% of maximal HR)

  • Symptom limited GXT (clients stops due to discomfort or abnormal physiological responses)

What are the pros and cons of Bench Stepping, Cycle ergometers and treadmill GXT?

Bench stepping

• Pros: low cost of equipment an portability,

• Cons: Difficult to take measurements, limited number of stages for a given fitness level

Cycle Ergometer (appropriate rpm 50 - 60 low to avg, 70 to 100 rpm competitive)

• Pros: HR and BP measurements relatively easy to take, safe for those with balance problems, instruments are moderately priced

• Cons: Pacing difficult to regulate, leg fatigue may stop a client to stop before reaching VO2 max, each increment in intensity places greater relative load on a smaller person

Treadmill

• Pros: Reproducible: treadmill maintains the speed, natural activity, acommodates all fitness levels

• Cons: Temptation to use the handrail, lack of portability, difficult to take measurements (e.g., BP), expense of equipment

  • Influences VO2 max based on test, (Graded runnning > running at 0% grade)

What are the protocols for GXT?

• Submaximal and maximal tests can use the same GXT protocol, but the criteria for test termination differ

• Maximal tests effectively identify ischemic heart disease

• Submaximal tests are useful in assessing fitness and are less expensive to administer

• VO2 max estimated from a submaximal test is not as accurate as VO2 max obtained from a maximal test

What plays a role in Maximal GXT?

• ACSM notes maximal testing is often not feasible in health and fitness testing

• Criteria to verify a maximal effort

  • Plateau in VO2 max with increased workload

  • No HR increase with increased workload

  • Postexercise blood lactate greater than 8 mmol per L

  • Peak respiratory exchange ratio (RER) greater than 1.10

How do we predict VO2 max from submaximal test data?

• HR response usually linear between 110 bpm and 85% HRmax

• Standard error of estimate (SEE) = 5ml /kg /min

• Very reliable for tracking progress over time, regardless of accuracy of estimated VO2 max

• Estimation based on submaximal HR responses; important to not conditions that affect HR

How do we predict VO2 max from submaximal test data in graphing?

• this method involves plotting HR responses (>110 bpm) to a GXT on a treadmill, cycle ergometer, or bench step

• A line is drawn through the HR values and is extrapolated to the subject’s age predicted estimate of maximal HR

• A vertical line is drawn to the x axis to estimate the work rate and VO2 the person would have achieved if it had been a maximal test

What factors affect responses HR, BP and RPE responses in a GXT?

• Temperature, humidity

• Amount of sleep before testing

• Emotional state

• Hydration status

• Medications

• TIme of day, last meal, Psychological environment

How do you estimate VO2 max from submaximal GXT on Cycle ergometer: Astrand and Rhyming Cycle Ergometer test?

• 1 work rate for 6min that results in a HR response between 125 and 170 bpm

• The HR mean for the final 2 minutes is used to estimate VO2 max.

• A nomogram or table can be used; the resulting value will require age correction.

What is the post test protocol?

• Active cool down procedure → rest

  • Decrease intensity, active recovery for 3 min

  • Monitor vitals till subject feels comfortable in sitting rest

  • Remove cuff and monitor when close to pretest values

• Instructions for 30 min before showering, warm water

• Discuss results, making an appointment

What are the pros and cons of field testing?

Pros:

• Moderate of high correlation of VO2 max

• Use of natural activities

• Ability to test large numbers in a short time

Cons:

• Difficult to monitor physiological responses

• Outcomes subject to other factors (motivation, environment)

• Lack of graded or submaximal testing protocols

What is the mile walk test?

• accomodates different ages and fitness levels

• Walk as fast as possible measuring HR at the end of the mile

What is the 6 min walk test?

• Use with individuals with reduced CRF

• Test is self paced; participants walk as far as possible on a level surface in 6 minutes

  • Senior fitness test uses a rectangular walking path measuring 20 yards by 5 yards

What is a run test?

• Run as fast as possible for 12 minutes or 1.5 miles.

• Run test is one of the most common CRF tests (easy to administer repeatedly and at low expense)

• Run time for VO2 max test is 12 to 15 minutes to diminish the anaerobic contribution

• Tends to underestimate VO2 max in children, and overestimates VO2 max in competitive runners and those who walk

What is the mile run for youth?

• For youth 10 to 17 y/o, BMI and age are considered along with the mile run time to predict anaerobic capacity.

What is the PACER?

• 20m progressive shuttle run

• Beginning pace of 5.3 mph and increasing 0.3 mph at each level

• CRF based on number of 20m laps completed

• Part of the FitnessGram testing battery for children

How do we estimate VO2 without doing an exercise test?

• Estimate with simple variables: age, gender, body fatness or BMI and self reported activity