Lactate Threshold Testing Lab Notes

Course Information: UTS, CRICOS 00099F, 92563 Applied Exercise Physiology.
Lab Focus: Conduct a lab assessment with practical skills, safety, and teamwork.

Main Aim: Conduct lab assessment focusing on:
- Competent preparation and conducting of athlete assessment.
- Accurate data collection to identify lactate thresholds.
- Importance of metabolic thresholds as indicators of exercise performance in endurance events.
Resources: All materials necessary for the lab can be found on Canvas.

Significance: Understanding lactate (LT1) and anaerobic thresholds (LT2) is essential for assessing metabolic stress.
Application: Thresholds guide exercise prescription and performance monitoring, assisting in evaluating fitness changes over time.

Defined as the intensity where lactate levels rise above resting or baseline levels.
Lactate Clearance vs. Production:
- Balance: Steady state is achievable when lactate production equals clearance.
- Identification: Recognized as the first 0.5 mmol/L rise above baseline or at 2.0 mmol/L.

Defined as the intensity where lactate begins to rise rapidly, indicating that lactate production exceeds clearance.
Physiological Changes: At this threshold, reliance on anaerobic energy supply increases, preventing steady state.
Identification: Typically occurs around 4.0 mmol/L (with a range of 3-5 mmol/L).

Team Setup: Groups of 5-6 with defined roles:
- Athlete Preparation: The athlete should not set up their own equipment.
- Team Leader Responsibilities: Download and share data sheet, timing, and data recording.
- Heart Rate: Fitting, pairing, monitoring, and perceived exertion (RPE).
- Bike Setup: Adjusting seat, handlebars, and setting resistance/workload/cadence.
- Temperature Monitoring: Tympanic and skin temperature collection (mark measurement site).
- Blood Lactate Measurement: Safe collection and disposal protocols.
Testing Procedure: Perform step test and record measurements during the last 60 seconds of each stage.
Support: Continuous monitoring (visual & verbal) by team members throughout the test.
Data Analysis: After testing, analyze and interpret collected data.

Ergometer Setup: Appropriate positioning of seat and handlebars, and workout initiation.
Heart Rate Monitor: Must be fitted correctly and paired with watch and ergometer.
Perceptual RPE: Should be anchored and appropriately prompted for accurate monitoring.
Temperature Measurement: Both tympanic and skin temperatures must be accurately recorded.
Blood Lactate: Ensure measurements are safe, reliable, and valid with proper disposal methods.
Lab Safety: Observe cleanliness and protocols regarding waste disposal.
Data Management: Efficient timekeeping and data recording by the team leader.

Missing Measurements: Clarification required on the process if a measurement is missed.
Pre-testing Conditions and Readiness:
- Confirm if the athlete has any chronic health conditions.
- Assess readiness for a maximal test based on training history and current fitness.
- Determine the protocol to estimate LT1 and LT2 based on athlete capability.
- Establish strategy for rest intervals during the test.
- Identify starting workload and target cadence for each workload.

Option 1 – Less Experienced Cyclists:
- Continuous steps of 3 minutes at 25 W increments starting:
- 50W for less trained individuals.
- 75W for individuals under 65kg and aerobically trained.
- 100W for individuals over 65kg and aerobically trained.
- Test Ends: When RPE > 9, volitional exhaustion, HR plateau, or cadence drops below 50 rpm.
Option 2 – More Experienced Cyclists:
- Continuous steps of 5 minutes at 50 W increments starting at 50W.
- Test Ends: As in Option 1.
Option 3 – Maximum Effort:
- Discontinuous steps of 4 minutes with 1 minute rest.
- Continue until blood lactate exceeds 3.5 mmol/L, then rest and conduct one maximal 4-minute effort.

Blood Lactate Measurement: Collect blood lactate values 3 minutes after completing all protocols to understand peak lactate levels.

Access: The data recording sheet can be downloaded from Canvas.
Data Entry: Save and share copies with teammates for collaborative efforts in recording test data.
Included Data: Such as heart rates, lactate levels, temperature, RPE, and durations.

Website: Utilize ExPhysLab at https://www.exphyslab.com/.
Input Data:
- Required details: number and length of steps, starting load, step increments, completion status of final step.
- Input Watts, Blood Lactate, and Heart Rate for analysis.
Curve Fitting: Select a third-degree polynomial, do not include baseline values, and download results.
Calculation for Thresholds:
- Use Log-Poly-ModDmax for LT2.
- Use Bsln + 0.5 for LT1.
Visuals: Include a screenshot of the lactate curve in the data recording sheet for better analysis.

Identified thresholds can guide personalized training programs and track training adaptations across various intensities:
- Increased speed/power at LT1 indicates enhanced base aerobic conditioning.
- Increased speed/power at LT2 indicates improved high-level aerobic endurance.

Lactate concentration in mmol/L over power output (W) vs heart rate (bpm).
Thresholds T1, T2, etc., identify critical points of lactate accumulation and performance.

Peak Oxygen Deficit at OBLA 4.0 mmol/L monitored over years:
- Year 1: 280 W
- Year 2: 350 W
- Year 3: 390 W
Adaptations: Can manifest as rightward and/or downward shifts in lactate threshold and metabolic responses.

Understanding lactate response to exercise and identification of metabolic thresholds (OBLA 2.0 and 4.0, Dmax, ModDmax, LTP1, LTP2).

Lactate Clearance: Explained how lactate is processed during exercise and recovery, mainly through the Cori Cycle and conversion to gluconeogenesis.
Difference between LT1 and LT2:
- LT1 denotes increased anaerobic support with production matching clearance, allowing steady state.
- LT2 signifies a shift to rapid lactate accumulation with production outpacing clearance, limiting sustained workloads.
Relevance of Anaerobic Threshold for Performance:
- LT2 is crucial for endurance, as it represents the upper limit for sustainable exercise. Time spent above LT2 could hinder performance due to lactate accumulation.
- Elite athletes can sustain workloads at LT2 for extended periods.
Factors affecting physiological responses:
- Factors include training load, nutritional status, psychological states, environmental conditions, exercise modes, and measurement validity.

Next Week: Focus on validating LT1 and LT2 and continued competency testing in exercise physiology assessment techniques.