Lactate Lab_and VT 2023

KIN 359 – 2022 MEASUREMENT OF THE BLOOD LACTATE RESPONSE TO GRADED EXERCISE AND DETERMINATION OF THE LACTATE AND VENTILATORY THRESHOLDS Data Analysis Perform the data analysis on the subject from your group using the data provided in Canvas. Danielle’s Data Collection Sheet Stage Time (Min) HR (bpm) RPE Workrate (W) Lactate VO2 (mL/kg/min ) Rest 0 100 6 60 3 0.45 1 3 116 7 80 1.4 1.10 2 6 146 9 100 5 1.54 3 9 155 12 120 9.1 1.77 4 12 173 13 140 8.3 2.18 5 D-N-C 173 15 160 7.7 2.18 … X X X X X X Rest X X X X X X Final 1 X X X X X X Final 2 X X X X X X 1. Create a table showing subject characteristics (height, weight, sex, age, VO2peak, etc.). (3 points) Danielle’ s Informati on Height Weight Sex Age VO2 Peak 1.753 m 70 kg Female 20 43.7 2. Construct a graph of blood lactate versus time. To visually determine the lactate threshold, determine the minute just before the onset of a systematic, sustained increase in lactate above baseline values. The exercise intensity or rate of aerobic metabolism during this minute is the lactate threshold. Identify it on the graph. Report the time at which the LT occurred, the corresponding VO2, relative intensity (%VO2peak), HR, RPE, and work rate. Report the data in a table similar to the one shown below. (5 points) 1

0 1 2 3 4 5 6 7 8 0.0 5.0 10.0 15.0 20.0 Lactate Prodction while Exercising Time (stages / min) Lactate (mmol) 3. Obtain 2 more estimates of the lactate threshold or OBLA. Specify and label the criterion ( highlighted below) you selected to determine each (e.g., 2 mmol/L above baseline or 4 mmol/L). Report the data in the same table as in #2 (similar to the one shown below). (5 points) 4. Determine Ventilatory Threshold using 3 different methods (you will need to construct a separate graph for each method (3 total)). Report results in a table similar to the one shown below. (9 points) Table example: Lactate Threshold Ventilatory Threshold Variable LT OBLA 2mmol OBLA 4mmol Ventilati on vs Watts V-Slope Vent Eq. Work Rate (Watts) V.O 2 (ml/kg/min) % V.O 2max Heart Rate (bpm) RPE 140 _25.72_ _58.8_ _143 _ __12___ _ 120_ __22.51_ __51.4__ __126___ ___8___ __160__ __29.76__ __68__ __158__ __14__ __140__ __25.72__ __58.8__ __143__ ___12___ __160__ __29.76__ __68__ __158__ ___14___ __220__ __43.73__ __100__ __191__ __20__ 2

1 2 3 4 5 6 7 8 9 0.00 5.00 10.00 15.00 20.00 25.00 30.00 35.00 40.00 Vent Eq. Ventilatory Threshold VE/VO2 VE/VCO2 Stages Vent. Eq. Present all graphs and tables here, above the discussion questions below. Answer the following questions (make sure to support your answers with your data): l. Did blood lactate change as expected as a function of relative exercise intensity? Explain (i.e., what was expected and what was observed?). How did the multiple estimates of the lactate threshold compare? (4 points) Blood lactate increased as the intensity of the workout (Watts) was increased. This is as you would suspect 2. Briefly summarize the physiological mechanisms that are thought to be responsible for the accumulation of lactate in the blood during graded exercise. (4 points) During graded exercise pyruvate becomes converted into lactate via the glycolysis cycle from the lactate dehydrogenase molecule. 3. Based on the subject’s lactate threshold, expressed both as %V.O 2max and absolute workrate, would you consider him or her to be an endurance trained or an untrained individual? Provide reasoning for your choice based on data discussed in lab or your textbook. (4 points) Based on the subject’s lactate threshold, expressed percentage of VO2 max and absolute work rate I would consider this individual to be in the upper echelon category of an untrained individual. 4. Compare VT and LT. Which method do you think is most valid? Why? (4 points) It depends on the form of activity that the subject is training for and what their specific goals are. Both methods are valid forms to determine the overall fitness of an individual. 5. How did the perceptions of exertion at the lactate and ventilatory thresholds compare in our subject? How do these ratings compare with the literature? (5 points) The ratings of perceived exertion (RPE) for the lactate and ventilatory thresholds were similar in our subject. Lactate was measured as a 12 and ventilatory threshold was 4

measured as a 14. The RPE is scored based on a 6 to 20 point scale, the ratings in the literature were similar to the RPE’s we collected meaning that our data may be valid. 6. Evaluate whether the subject reached a true max during the test (support with data). (3 points) The subject did reach a true max during the test because she was unable to complete the final stage of the exercise. 7. Discuss the implications of the lactate threshold on exercise performance and fatigue. Based on the data from lab, would they perform better or worse than a participant with a VO 2 max of 50 mL/kg/min and a lactate threshold of 60% of their VO 2 max on a cycling time trial on a flat road? Provide rationale. (5 points) Lactate Threshold is used as a predictor of an individual’s endurance. Someone who has a high lactate threshold is ideal for long distance and drawled out extraneous activity. Based on the data we collected our subjects VO2 max was 43.73 which is less than 50 mL/kg/min and the lactate threshold percentage of VO2 max was less than 60% therefore indicating that their overall performance is less than the provided. This means that our subject would have a more difficult time cycling on a flat road than the participant in the question due to the lower overall fitness levels. 8. Based on the physiological mechanisms involved in lactate accumulation, explain how a 6- month endurance training program would affect lactate threshold. Why (physiological mechanisms)? (4 points) A 6-month training regime would improve the subjects Lactate Threshold, due to the increase in their endurance performance. Interval running trains your muscles allowing them to surpass the current lactate threshold whilst also increasing the efficiency of used oxygen. In Class Notes VO2 Max is a great predictor for aerobic fitness Lactate threshold is why records continue to be broken, and you continue to improve although VO2 max has been reached. Three different Ways to determine Lactate Threshold (1) Visual (2) 2 Above Base (3) 4 mmol 5