Work Tests to Evaluate Performance

Objectives Discuss the factors that determine the effectiveness of a physiological test of athletic performance. Define “specificity of VO2 max.” Explain the difference between VO2 max and VO2 peak. Discuss the physiological rationale for the assessment of the lactate threshold in the endurance athlete. Describe methods for the assessment of anaerobic power. Discuss the techniques used to evaluate strength.

Outline Determination of Anaerobic Power Tests of Ultra Short-Term Maximal Anaerobic Power Tests of Short-Term Anaerobic Power Evaluation of Muscular Strength Criteria for Selection of a Strength-Testing Method Isometric Measurement of Strength Free-Weight Measurement of Strength Isokinetic Assessment of Strength Variable-Resistance Measurement of Strength Laboratory Assessment of Physical Performance Physiological Testing: Theory and Ethics What the Athlete Gains by Physiological Testing What Physiological Testing Will Not Do Components of Effective Physiological Testing Direct Testing of Maximal Aerobic Power Specificity of Testing Exercise Test Protocol Determination of Peak VO2 in Paraplegic Athletes Laboratory Tests to Predict Endurance Performance Use of the Lactate Threshold to Evaluate Performance Measurement of Critical Power Tests to Determine Exercise Economy Estimating Success in Distance Running Using the Lactate Threshold and Running Economy

Physiological Testing: Theory and Ethics Laboratory Assessment of Physical Performance Physiological Testing: Theory and Ethics Physical performance is determined by: Capacity for maximal energy output Aerobic and anaerobic Muscular strength Coordination/economy of movement Psychological factors Motivation and tactics Laboratory test should stress the same physiological systems required by sport or event Athletes should volunteer for testing

Factors That Contribute to Physical Performance Laboratory Assessment of Physical Performance Factors That Contribute to Physical Performance Figure 20.1

What the Athlete Gains From Physiological Testing Information regarding strengths and weaknesses Can serve as baseline data to plan training programs Feedback regarding effectiveness of training program Education about the physiology of exercise

What Physiological Testing Will Not Do Difficult to simulate sports in laboratory Physiological and psychological demands Difficult to predict performance from single battery of tests Performance in the field is the ultimate test of athletic success

Components of Effective Physiological Testing Physiological variables tested should be relevant to the sport Tests should be valid and reliable Tests should be sport-specific Tests should be repeated at regular intervals Testing procedures should be carefully controlled Test results should be interpreted to the coach and athlete

Components of Effective Physiological Testing In Summary Designing laboratory tests to assess physical performance requires an understanding of those factors that contribute to success in a particular sport. Physical performance is determined by the interaction of the following factors: (a) maximal energy output, (b) muscular strength, (c) coordination/economy of movement, and (d) psychological factors such as motivation and tactics. In order to be effective, physiological tests should be: (a) relevant to the sport; (b) valid and reliable; (c) sport specific; (d) repeated at regular intervals; (e) standardized, and (f) interpreted to the coach and athlete.

Direct Testing of Maximal Aerobic Power VO2 max is considered the best test for predicting success in endurance events Other factors are also important Better predictor in heterogeneous groups Most accurate means of measurement is direct testing in laboratory Open-circuit spirometry Specificity of testing Should be specific to athlete’s sport Runners tested on treadmill

Exercise Test Protocol Direct Testing of Maximal Aerobic Power Exercise Test Protocol Should use large muscle groups Optimal test length 10–12 minutes Start with 3–5 minute warm-up Increase work rate to near maximal load Increase load stepwise every 1–4 minutes until subject cannot maintain desired work rate Criteria for VO2 max Plateau in VO2 with increasing work rate Rarely observed in incremental tests Blood lactate concentration of >8 mmoles•L–1 Respiratory exchange ratio 1.15 HR in last stage 10 beats•min–1 of HRmax

Determining VO2 Max Direct Testing of Maximal Aerobic Power Figure 20.1

Determination of Peak VO2 in Paraplegic Athletes Direct Testing of Maximal Aerobic Power Determination of Peak VO2 in Paraplegic Athletes Paraplegic athletes can be tested using arm exercise Arm ergometers Wheelchair ergometers Highest VO2 measured during arm exercise is not considered VO2 max Called “peak VO2” Higher peak VO2 using accelerated protocol Test starts at 50–60% of peak VO2 Limits muscular fatigue early in test

Direct Testing of Maximal Aerobic Power In Summary The measurement of VO2 max requires the use of large muscle groups and should be specific to the movement required by the athlete in his or her event or sport. A VO2 max test can be judged to be valid if two of the following criteria are met: (a) respiratory exchange ratio >1.15, (b) HR during the last test stage that is ±10 beats per minute within the predicted HRmax, and/or (c) plateau in VO2 with an increase in work rate. Arm crank ergometry and wheelchair ergometry have been used to determine the peak VO2 in paraplegic athletes.

Laboratory Tests to Predict Endurance Performance Peak running velocity Highest speed that can be maintained for >5 sec Lactate threshold Exercise intensity at which blood lactic acid begins to systematically increase Direct measurement Estimation by ventilatory threshold Critical power Speed at which running speed/time curve reaches plateau

Laboratory Tests to Predict Endurance Performance Research Focus 20.1 Measurement of Peak Running Velocity to Predict Performance Peak running velocity Tested on treadmill or on track Progressively increasing speed on treadmill Highest speed that can be maintained for >5 sec Excellent predictor of 5 km run performance Strong correlation r = –0.97 Also a good predictor of 10–90 km race performance

Relationship Between Peak Running Velocity and 5-km Race Performance Laboratory Tests to Predict Endurance Performance Relationship Between Peak Running Velocity and 5-km Race Performance Figure 20.3

Use of the Lactate Threshold to Evaluate Performance Laboratory Tests to Predict Endurance Performance Use of the Lactate Threshold to Evaluate Performance Lactate threshold estimates maximal steady-state running speed Predictor of success in distance running events Direct determination of lactate threshold (LT) 2–5 minute warm-up Stepwise increases in work rate every 1–3 minutes Measure blood lactate at each work rate LT is the breakpoint in the lactate/VO2 graph Prediction of the LT by ventilatory alterations Ventilatory threshold (Tvent) Point at which there is a sudden increase in ventilation Used as an estimate of LT

Lactate Threshold Laboratory Tests to Predict Endurance Performance Figure 20.4

Ventilatory Threshold Laboratory Tests to Predict Endurance Performance Ventilatory Threshold Figure 20.5

Measurement of Critical Power Laboratory Tests to Predict Endurance Performance Measurement of Critical Power Critical power Running speed at which running speed/time curve reaches a plateau Power output that can be maintained indefinitely However, most athletes fatigue in 30–60 min when exercising at critical power Measurement of critical power Subjects perform series of timed exercise trials to exhaustion Prediction of performance in events lasting 3–100 minutes Highly correlated with high VO2 max and LT

Concept of Critical Power Laboratory Tests to Predict Endurance Performance Concept of Critical Power Figure 20.6

Laboratory Tests to Predict Endurance Performance In Summary Common laboratory tests to predict endurance performance include measurement of the lactate threshold, critical power, and peak running velocity. All of these measurements have been proven useful in predicting performance in endurance events. The lactate threshold can be determined during an incremental exercise test using any one of several exercise modalities (e.g., treadmill, cycle ergometer, etc.). The lactate threshold represents an exercise intensity at which blood lactic acid levels begin to systematically increase.

Laboratory Tests to Predict Endurance Performance In Summary Critical power is defined as the running speed (i.e., power output) at which the running speed/time curve reaches a plateau. Peak running velocity (meters•second–1) can be determined on a treadmill or track and is defined as the highest speed that can be maintained for more than five seconds.

Tests to Determine Exercise Economy Higher economy means that less energy is expended to maintain a given speed Runner with higher running economy should defeat a less economical runner in a race Measurement of the oxygen cost of running at various speeds Plot oxygen requirement as a function of running speed Greater running economy reflected in lower oxygen cost

The Oxygen Cost of Running for Two Subjects Tests to Determine Exercise Economy The Oxygen Cost of Running for Two Subjects Figure 20.7

Estimating Distance Running Success Using LT and Running Economy Close relationship between LT and maximal pace in 10,000 m race Race pace at 5 m•min–1 above LT Predicting performance in a 10,000-m race Measure VO2 max Plot VO2 vs. running speed Determine lactate threshold Plot blood lactate vs. VO2 VO2 at LT = 40 ml•kg–1•min–1 VO2 of 40 ml•kg–1•min–1 = running speed of 200 m•min–1 Estimated 10,000 m running time 10,000m  205 m•min–1 = 48.78 min

Running Economy and LT Results from Incremental Exercise Test Estimating Distance Running Success Running Economy and LT Results from Incremental Exercise Test Figure 20.8

Estimating Distance Running Success In Summary Success in an endurance event can be predicted by a laboratory assessment of the athlete’s movement economy, VO2 max, and lactate threshold. These parameters can be used to determine the maximal race pace that an athlete can maintain for a given racing distance.

Determination of Maximal Anaerobic Power Determination of Anaerobic Power Determination of Maximal Anaerobic Power Testing should involve energy pathways used in the event Ultra short-term tests ATP-PC system Short-term tests Anaerobic glycolysis

Energy System Contribution During Maximal Exercise Determination of Anaerobic Power Energy System Contribution During Maximal Exercise Figure 20.9

Tests of Ultra Short-Term Anaerobic Power Determination of Anaerobic Power Tests of Ultra Short-Term Anaerobic Power Tests ATP-PC system Power tests Jumping power tests Running power tests American football Series of 40-yard dashes with brief recovery between Soccer Intermittent shuttle tests Cycling power tests Quebec 10-second test

Series of 40-yard Dashes to Test Anaerobic Power Determination of Anaerobic Power Series of 40-yard Dashes to Test Anaerobic Power Figure 20.10

Classification of Football Players Based on 40-Yard Dash Times Determination of Anaerobic Power Classification of Football Players Based on 40-Yard Dash Times

Tests of Short-Term Anaerobic Power Determination of Anaerobic Power Tests of Short-Term Anaerobic Power Tests anaerobic glycolysis Cycling tests Wingate test Subject pedals as rapidly as possible for 30 seconds against predetermined load (based on body weight) Peak power indicative of ATP-PC system Percentage of peak power decline is an index of ATP-PC system and glycolysis Running tests Maximal runs of 200–800 m Sport-specific tests

Resistance Setting for Wingate Test Determination of Anaerobic Power Resistance Setting for Wingate Test

Determination of Anaerobic Power In Summary Anaerobic power tests are classified as: (a) ultra short-term tests to determine the maximal capacity of the ATP-PC system and (b) short-term tests to evaluate the maximal capacity for anaerobic glycolysis. Ultra short-tem and short-term power tests should be sport-specific in an effort to provide the athlete and coach with feedback about the athlete’s current fitness level.

Evaluation of Muscular Strength Maximal force that can be generated by a muscle or muscle group Assessed by: Isometric measurement Static force of muscle using tensiometer Free weight testing Weight (dumbbell or barbell) remains constant 1 RM lift, handgrip dynamometer Isokinetic measurement Variable resistance at constant speed Variable resistance devices Variable resistance over range of motion

Measurement of Maximal Isometric Force During Knee Extension Evaluation of Muscular Strength Measurement of Maximal Isometric Force During Knee Extension Figure 20.11

Handgrip Dynamometer to Assess Grip Strength Evaluation of Muscular Strength Handgrip Dynamometer to Assess Grip Strength Figure 20.12

Isokinetic Assessment of Knee Extension Evaluation of Muscular Strength Isokinetic Assessment of Knee Extension Figure 20.13

Printout From Isokinetic Dynamometer During a Knee Extension Evaluation of Muscular Strength Printout From Isokinetic Dynamometer During a Knee Extension Figure 20.14

Evaluation of Muscular Strength In Summary Muscular strength is defined as the maximum force that can be generated by a muscle group. Evaluation of muscular strength is useful in assessing training programs for athletes involved in power sports or events. Muscular strength can be evaluated using any one of the following techniques: (a) isometric, (b) free-weight testing, (c) isokinetic, or (d) variable-resistance devices.

Study Questions Discuss the rationale behind laboratory tests designed to assess physical performance in athletes. How do these tests differ from general physical fitness tests? Define maximal oxygen uptake. Why might relative VO2 max be the single most important factor in predicting distance running success in a heterogeneous group of runners? Discuss the concept of “specificity of testing” for the determination of VO2 max. Give a brief overview of the design of an incremental test to determine VO2 max. What criteria can be used to determine the validity of a VO2 max test? Briefly, explain the technique employed to determine the lactate threshold and the ventilatory threshold. Describe how the economy of running might be evaluated in the laboratory.

Study Questions Discuss the theory and procedures involved in predicting success in distance running. Explain how short-term maximal anaerobic power can be evaluated by field tests. Describe how the Wingate test is used to assess medium-term anaerobic power. Provide an overview of the 1-RM technique to evaluate muscular strength. Why might a computer-assisted dynamometer be superior to the 1-RM technique in assessing strength changes? Discuss the advantages and disadvantages of each of the following types of strength measurement: (1) isometric, (2) free weights, (3) isokinetic, and (4) variable resistance.