SHERRIDEN BYRNE AND TRACEY YOUNG

Vo2 Max and LIP testing in elite and non elite athletes

Introduction

VO2 Max & Lactate Inflection Point (LIP)Determinants of LIPRelationship between LIP and VO2 MaxGender differences in LIPGender Differences in VO2 MaxDifferences between trained/untrained athletes,

Chronic adaptations to exerciseVO2 Max and LIP test procedureResults discussionConclusion

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

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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.

AgeHeart RateStroke volumeHaemoglobin concentration Bicarbonate levels

Gender differences in LIP

2 Volunteers: Male and femaleWho 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

btc.montana.edu/Olympics/physiology/pb02.html

• 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

Trained/untrained differences Chronic adaptation to exercise

http://www.sport-fitness-advisor.com/lactate-threshold.html

•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

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.

Trained/untrained differences Chronic adaptation to exercise

Assistants

Warm up – calculate 20% HR and warm up on treadmill

TimerSpeed setterHeart rate monitorRecorder

Heart rate Perceived Rate of Exertion Anecdotal comments

Lactate measurement Enter results into computerCool down

Test Procedure

Warm up on treadmill until their HR is approx 20% of their Vo2 Max

Start the test – treadmill at 3% inclineAfter 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

Results

Conclusion

Trained/untrained Chronic adaptations