Vo2 Max and LIP testing in elite and non elite athletes Sherriden Byrne and Tracey Young
Introduction • VO2 Max & Lactate Inflection Point (LIP) • Determinants of LIP • Relationship between LIP and VO2 Max • Gender differences in LIP • Gender Differences in VO2 Max • Differences between trained/untrained athletes, Chronic adaptations to exercise • VO2 Max and LIP test procedure • Results discussion • Conclusion
Lactate Inflexion Point (LIP) • The Lactate Inflection Point is the point at which lactic acid starts to accumulate in the blood stream as it is being produced faster than it can be removed. • If exercise intensity increases beyond the LIP then the athlete has to reduce or stop muscle effort. • When exercising below the LIP intensity any lactate produced by the muscles is removed by the body without it building up. The lactate threshold is a useful measure for deciding exercise intensity for training and racing in endurance sports.
Lactate Inflexion Point bp0.blogger.com/.../E5_KlzXmnAA/s400/lactate.JPG
Relationship between LIP and Vo2 Max • LIP is normally expressed as a percentage of an individuals VO2 Max therefore reflects the maximum capacity of the aerobic system. • For example, if Paul’s VO2 max occurs at 24 km/h on a treadmill test and a sharp rise in blood lactate concentration above resting levels is seen at 12 km/h then the LIP is said to be 50% VO2 max. • If Joey’sVo2 Max occurs at 30 km/h and a sharp rise in blood lactate concentration is seen at 22 km/h what would the LIP be? • Who do you think is more likely to be a trained athlete and why?
Determinants of LIP • Training: Trained athletes have a higher LIP relative to their VO2 Max as LIP occurs at a higher intensity of exercise. • Age • Heart Rate • Stroke volume • Haemoglobin concentration • Bicarbonate levels
Gender differences in LIP • 2 Volunteers: Male and female • Who would have a better Lactate Inflexion Point? Why? • Little or no difference is seen in the Lactate Inflexion Point results in equally trained/untrained men and women. • Reflects state of fitness not gender
Gender Differences in Vo2 Max • Two volunteers: male and female • Who would have a better Vo2 Max and why? • Healthy untrained women 15%- 30% below the scores for men • Trained athletes 10%-20% • Differences attributed to • Body composition (body fat) • Blood’s haemoglobin concentration • Lung Volume • Heart size btc.montana.edu/Olympics/physiology/pb02.html
Trained/untrained differences Chronic adaptation to exercise • Lung volume increases • Vo2 Max increases up to 30% • Recovery heart rate returns to resting levels faster • Lactate Inflexion Point increases • Stroke volume increases • Blood volume increases • Haemoglobin count increases • Volume of left ventricle increases after aerobic training • Hypertrophy of left ventricle occurs after anaerobic training • Max heart rate remains the same http://www.sport-fitness-advisor.com/lactate-threshold.html
Trained/untrained differences Chronic adaptation to exercise • As the exercise intensity draws closer to VO2 max • sharp increase in blood lactate accumulation • fatigue occurs • lactate threshold is broken. • In world-class athletes lactate threshold typically occurs at 70-80% VO2 max. • In untrained individual’s it occurs at about 50-60% VO2 max • Generally, in two people with the same VO2 max, the one with a higher lactate inflexion point will perform better in endurance events.
Assistants • Warm up – calculate 20% HR and warm up on treadmill • Timer • Speed setter • Heart rate monitor • Recorder • Heart rate • Perceived Rate of Exertion • Anecdotal comments • Lactate measurement • Enter results into computer • Cool down
Test Procedure • Warm up on treadmill until their HR is approx 20% of their Vo2 Max • Start the test – treadmill at 3% incline • After 5 minutes • Straddle the treadmill • Increase the treadmill by 0.5km/hr • Take blood lactate reading • Take heart rate reading • Ask the subject for their PRE • Continue to increase treadmill speed and take readings until termination
Conclusion • Trained/untrained • Chronic adaptations