CHAPTER 13: Measuring Endurance, Anaerobic Capacity and Strength

LECTURE OUTLINE:

• I. Metabolic Determinants of Physiological Capacities
  • A. Figure 13.1 different categories of events/activities relating to metabolic and physiological capacities that contribute to them.
• II. Measuring Cardio-respiratory and Muscular Endurance
  • A. Maximal Oxygen Consumption
    • 1. VO2max - the maximal rate of oxygen uptake and utilization by the body. The test of maximal oxygen uptake must meet several requirements in order for the test to be considered maximal vs. peak.
      • a. may not be an accurate assessment of the cardiorespiratory demands of submaximal exercise.
      • b. Direct vs. indirect measurement
      • c. Markers of attainment of VO2max (table 13.1)
        • i. plateau in VO2
        • ii. RER > 1.1
        • iii. HRmax< 10b/min from predicted
    • 2. VO2peak - the maximal rate of oxygen uptake and utilization by the body at voluntary volitional fatigue.
    • 3. Testing Protocols
      • a. average duration should be 8-12 minutes - test > 16min can lower VO2max; tests < 8 min have large increment in intensity and can lead to premature fatigue
      • b. Testing on a treadmill with grades favors the runner who runs hills frequently during training.
      • c. tailor a protocol to suit a give individual - fitness level, mode of training
      • d. If test is terminated by angina, abnormal ECG, dyspnea, or leg fatigue because of claudication it is called symptom-limited VO2max or VO2peak
      • e. estimated oxygen uptake (table 13.2 and 13.3)
  • B. Predicting Cardiorespiratory and Muscular endurance
    • 1. ACSM equations (table 13.2) used to calculate submaximal VO2 during treadmill, cycle ergometry, arm ergometry and step testing. Latin, et al. equation more accurate than ACSM for cycle ergometry
    • 2. Predicting VO2max can be done with maximal or submaximal exercise
      • a. risks may be too high for maximal testing
      • b. most prediction equations were developed using healthy, young subjects, not older individuals with various degenerative diseases.
      • c. prediction of VO2max is dependent on measuring variables that are known to change proportionately with VO2; HR, Change in HR, exercise duration for a given protocol.
      • d. HR commonly used but influenced by dehydration, arousal, type of exercise, caffeine, etc, and individual variability
      • e. prediction based on HR is prone to considerable error.
    • 3. Maximal
      • a. treadmill protocols (table 13.2 figure 13.2)
      • b. cycle ergometer protocols
      • c. 1 Watt = 6.118 kgm/min
      • d. 15 Watt/min increment = 92 kgm/min
    • 4. Submaximal methods (table 13.4)
      • a. treadmill protocols (equations 13.1 and 13.2)
      • b. cycle protocols (figure 13.3 and 13.4)
      • c. Astrand-Rhyming nomogram - a submaximal cycle ergometer test used to predict VO2max
        • i. astrand: HR taken at 5 and 6 minutes, if differ by more than 5 b/min do one extra minute. Average the two HRs. If HR <130 b/min increase intensity by 50 W.
        • ii. data is final power output in Watts and final HR.
      • d. Potential errors (individual variability with HR responses to exercise)
    • 5. Cooper's 1.5 mile run - O2 uptake predicted by a formula
    • 6. Rockport walk test
    • 7. Step test
  • C. Lactate and Ventilatory Thresholds
    • 1. General Information
      • a. best measure for success in running longer than 1,500 m is VO2 at the lactate threshold
      • b. reflects maximal steady state intensity
      • c. LT may be a more valid measure of careiorespiratory endurance than VO2max.
      • d. LT and VO2max provide the best combined measure of cardiorespiratory endurance.
      • e. Blood samples
      • f. Detecting LT; graphing BL vs some measure of exercise intensity (VO2, watts, running velocity, etc.)
      • g. Figure 13.5 (plotting the LT)
    • 2. Methods for Detecting the LT
      • a. visual detection is no longer acceptable (13.5)
      • b. lactate turnpoint (figure 13.5)
      • c. other methods
    • 3. The Ventilatory Threshold figure 8.10
      • a. non-invasive technique to plot LT
      • b. VE method
      • c. VE/VCO2 - VE/VO2 method
      • d. Similarities and dissimilarities between ventilatory threshold and LT - The physiological explanation for an increase in ventilation to correspond to an increase in blood lactate accumulation has been based on the acidosis and increased venous blood PCO2 that accompanies lactate production. However, the exact mechanism that casue the increase in ventilation are unclear as PaCO2 actually decreases during incremental exercise at intensities above the LT because of hyperventilation, and threshold increases in ventilation have been demonstrated in individuals who were not acidic. Nevertheless, LT and VT are excellent predictors in success in prolonged endurance exercise.
  • D. Running Economy
    • 1. Running Economy - involves a low submaximal VO2, and therefore the ability to run faster at a given percent of the lacate threshold or VO2max
    • 2. figure 13.6 (running efficiency)
  • E. VO2 Kinetics
    • 1. VO2 kinetics is measured by change in VO2 for a given increase in exercise intensity.
  • F. Heart Rate Threshold
    • 1. conflicting results from different studies over the similarity/dissimilarity between LT and HR

III. Measuring Maximal Muscle Power and Anaerobic Capacity

• A. Measuring Maximal Muscle Power
  • 1. tests of muscle power are categorized according to the length of test
  • 2. short-term tests (<10 seconds)
    • a. Sargent's Jump and Reach Test
    • b. Margaria Power Test
  • 3. intermediate-term anaerobic tests (between 20 to 60 seconds)
    • a. Wingate test
    • b. Isokinetic tests (figure 13.7)
  • 4. long-term anaerobic tests (60 to 120 seconds)
    • a. Anaerobic capacity - reflects the ability to regenerate ATP from non-mitochondrial sources.
    • b. muscle metabolic accumulation
    • c. Accumulated oxygen deficit - the difference between the total energy requirements of exercise by calculating the theoretical VO2 required for the exercise intensity and subtracting from this value the measured VO2. This measure reflects anaerobic capacity (figure 13.8)
    • d. Accumulated oxygen deficit values (figure 13.9)

IV. Strength

• A. Muscular strength - defined as the maximal force exerted by a muscle or muscle group at a specific velocity.
• B. Muscular Strength Testing Equipment
  • 1. Dynamometer - an inexpensive device used to measure static strength (table 3.5)
  • 2. Cable tensiometer - isometric testing
  • 3. 1 repetition maximum (1 RM) - the amount of weight that can be lifted in one repetition.
• C. Interpreting Results of Muscular Strength Tests
  • 1. specific to the muscle group tested
  • 2. table 13.6 (norms for grip strength)
  • 3. table 13.6 (norms for strength relative to body weight for 1 RM bench press).