7What is the Lactate Threshold (LT)? La- production exceeds removal in bloodLa- rises in a non-linear fashionRest [La-] 1 mM blood (max mM)LT represents first break-point on the lactate intensity curve: in glycogenolysis and glycolytic metabolism recruitment of fast-twitch motor unitsexceeding mitochondrial capacity for pyruvatepyruvate converted to lactate to regenerate NAD+ so glycolysis can continue redox potential (NAD+/NADH)
8Other LT Terminology Anaerobic threshold (no longer used) First used in 1964Based on association of blood La- with hypoxiaMaximal lactate at steady state (MLSS) or Onset of blood lactate accumulation (OBLA)Upper limit of blood lactate that results in a lactate steady state during prolonged exerciseCan vary between 3 and 8 mmol/LUsually ~ 4 mmol/L
9Formation of Lactate is Critical to Cellular Function Does not cause acidosis related to fatiguepH in body too high for Lactic Acid to be formedAssists in regenerating NAD+ (oxidizing power)No NAD+, no glycolysis, no ATPRemoves H+ when it leaves cell: proton consumerHelps maintain pH in muscleSubstrate for glucose/glycogen
10Oxygen Uptake and Exercise Domains LCONSTANTLOADLTMLSSSevere44HeavyVO2 (L/min)Severe22ModerateHeavyModerate1503001224Work Rate (Watts)Time (minutes)
11Ventilatory Thresholds Minute ventilation-O2 uptake (VE-VO2) relation during incremental exercise has 2 inflection points:Ventilatory threshold (VT): point of a non-linear increase in VE with respect to VO2Respiratory compensation point (RCP): onset of hyperventilation (respiratory compensation) during incremental exercise – a steeper increase in VE vs VO2 than VT
12Ventilatory Threshold VT corresponds closely with LT (r = .93); ~ 30 sec difference between LT and VT200150VTVE (L/min)1005080100120140160180Heart Rate
13Respiratory Compensation Point RCP is positively related to VO2max200150RCPVE (L/min)1005080100120140160180Heart Rate
14Heart Rate ThresholdHR doesn’t increase linearly as a function of VO2 in all peopleCan lead to errors in predicting VO2maxPoint where HR-VO2 relation deviates from linearity:Heart Rate Threshold (HRT)Heart Rate Deflection Point
15Heart Rate and VO2max % of Maximal Heart Rate % of VO2max 100 90 80 70 6050403020406080100% of VO2max
16Heart Rate Performance Curve A Initial speed: 5 mph increase by 0.31 mph every minuteRosic et al. Acta Physiologica Hungarica. 2011;98:59–70.
17Heart Rate Performance Curve B Initial speed: 5 mph increase by 0.62 mph every minuteRosic et al. Acta Physiologica Hungarica. 2011;98:59–70.
18Heart Rate Performance Curve C Initial speed: 6.2 mph increase by 0.31 mph every minuteRosic et al. Acta Physiologica Hungarica. 2011;98:59–70.
19EconomyEconomy: energy cost of exercise, "economy of movement”, rate of energy expenditure during runningO2 cost to run/cycle at a given speed by interval, plyometric, explosive strength (low load and maximal velocity), and high intensity interval trainingMeasure VO2 at 3 speeds between 6 and 12 mph
20Economy of Two Runners Cycling: Running: Physiology Seat height Pedal cadenceShoesWind resistanceRunning:Stride lengthBraking on foot strikeMechanical factors, including vertical displacement and so-called braking on foot strikeHigher economy suggests fuel use would be lower and perhaps glycogen depletion delayed.Second, metabolic heat production would also be lower, potentiallyreducing thermal stress.
21Velocity at Maximal Aerobic Power or vVO2max Running speed that elicits VO2maxUsed by coaches to set training velocity.Different methodologies used to establish:Extrapolation from treadmill testDerived from track runsHigher in endurance runners than sprinters.Improved by endurance trainingGood indicator of endurance performance in middle- and long-distance running events
22Velocity at Maximal Heart Rate and Oxygen Uptake 120130150170190200180160140706050Heart Rate (bpm)Oxygen Uptake (ml/kg/min)40Velocity at VO2maxor vVO2max30205.06.07.08.09.010.011.0Treadmill Speed (mph)
23Predicting Performance From Peak Running Velocity
24Training to Improve Performance Goals: VO2maxShift LT and MLSS to right Anaerobic power/capacity Economy of movementTraining methodsInterval training (High intensity)High-intensity, continuous exerciseSprints/Accelerations/Speed Play (Fartlek)Hill temposLong, slow distanceStrength training
25Types of Exercise Performance Tests VO2max for aerobic power and capacityWingate and Running tests for anaerobic power, capacity, and fatigue indexSubmaximal cycle/running tests - are more sensitive to training and yield valuable information regarding the training status.Functional Movement Screening
26Key Training and Performance Principles OverloadProgressionFITT: Frequency, Intensity, Time, TypeSpecificityIndividualismAdaptationReversibilityPeriodization
27Guidelines for Interval Training % of Max Anaerobic PowerEnergy SystemInterval TimeWork to Rest Ratio90-100CP5-10 s1:12 to 1:2075-90CP-LA15-30 s1:3 to 1:530-75LA-Aer1-3 m1:3 to 1:420-35Aerobic> 3 m1:1 to 1:3
28Long, Slow Distance Low-intensity exercise 57% VO2max or 70% HRmaxDuration > than expected in competitionBased on idea that training improvements are based on volume of training
29High-Intensity, Continuous Exercise May be best method for increasing VO2max LT, MLSS, and economyHigh-intensity exerciseRepeated exercise bouts (30 sec at intensity ~ % VO2max or % HRmax) separated by short (30 sec), light activity recovery periodsSlightly above MLSSDuration of minDepends on individual fitness levelVO2max more likely to be reached when work intervals are intense and rest intervals short.
31Anaerobic Power and Capacity Depends on ATP-PC energy reserves and maximal rate at which energy can be produced by ATP-PCR system.Maximal effortCyclists and speed skaters highest.
32Anaerobic Power Tests Margaria-Kalamen Power Stair Test Standing broad jumpVertical jump35 m (40 yd) sprintsWingate TestStair Test- flight of 12 steps with a starting line of 6 meters in front of the first step. Each step is approximately 17.5 cm high with the 3rd, 6th and 9th step clearly marked. The vertical distance between the 3rd and 9th step must be accurately measured for use in the results formula.
33Wingate Test for Anaerobic Power Mechanically-braked bicycle ergometer.After 10 min warm up, athlete begins pedaling as fast as possibleA fixed resistance is applied by 3 sec and athlete continues to pedal "all out" for 30 secCalculate peak/mean power output, anaerobic fatigue, and anaerobic capacity
34Wingate Test for Anaerobic Power Peak Power (PP): energy generating capacity of immediate energy system (ATP and CP).Highest power output during first 5 sec of testRelative PP (RPP) = PP/Body mass (kg)Average Power (AP): energy generating capacity of short-term energy system (LA-CP glycolysis).
35Wingate Test for Anaerobic Power Anaerobic Fatigue (AF): total capacity to produce ATP via immediate and short term energy systems - % decline in power output.AF = (Highest PP - Lowest PP)*100 /Highest PPAnaerobic Capacity (AC): maximum amount of work that can be produced from immediate energy system.AC = Average power X 30 sec or sum of power over 30 sec.
37Comparison to HPL Data45%tile20%tile~15%tile<10%tile
38Running-Based Anaerobic Sprint Test 400 meter track with straight, 35 m marked sectionComplete six 35 m sprints at max pace (10 sec between sprints for turnaround)Record time for each sprint to 0.01 secCalculate Power = (Weight × Distance²)/Time³Maximum power: highest valueMinimum power: lowest valueAverage power: sum of all six values ÷ 6Fatigue Index: (Maximum - Minimum power) ÷ Total time for 6 sprints
39Series of 40-yard Dashes to Quantify Anaerobic Power
40Training for Improved Anaerobic Power ATP-PC systemShort: 5-10 sec high-intensity work intervals30-60 sec rest intervalsGlycolytic systemShort: sec high-intensity work intervals1.2-4 min rests intervalsAerobic System:Short: sec high-intensity work intervalssec rest intervals
41Relative Contribution of Aerobic Energy to Total Energy
43What is FMS? Series of movements designed to screen for: FlexibilityBody movement asymmetryCore muscle weaknessScreening can potentially predict injuryIf we can predict it, we can prevent itFind the weak link and fix it!Less Injuries =Decreased training lossesBetter soldier retentionLess use of medical resourcesSave money
44What is FMS? 7 fundamental movement patterns Graded by trained examinerEach movement graded 0 to 3Able to target problem movementsCreates individual functional baselineSimple, quick, reproducibleDeficits corrected by physical therapy program
457 Movements Deep Squat Hurdle Step In-Line Lunge Shoulder Mobility Straight Leg RaisePush-UpRotational Stability
46FMS Scores by Cycle Length Mean FMS Scores: Long 16.5 ± 1.5 vs. Short 16.7 ± 1.9% of Scores ≤ % (36)13.1% (57)
47Injury Incidence Rates by FMS Scores: ≤14 and >14 CycleScorenTotal Training DaysInjured (n)Rate/ 1,000 person -daysRisk Ratio95%CIPLong≤14361,961199.691.65( ).03>1439122,2801315.89Short571,7142313.421.91( )<.0139013,822977.02
49Case 1: 37 year old, 84.5 kg, male runner Wants to 10k run time by 40 secVO2max = 60 ml/kg/minVT = 50.1 ml/kg/minLT = 45.2 ml/kg/minVT = 83.5% and LT = 75.2% of VO2maxPossible Recommendations:sec sprints at vVO2max8 X 400 m repeats at 1 mile pace with 400 m recovery
50Case 2: 27 year old, 120 kg male weightlifter Wants to upper body strengthVO2max = 30.1 ml/kg/minVT = 15.1 ml/kg/minPeak/Minimal Power = 1,111/306 Watts;VT = 50% of VO2max and AF = 72.5%Possible Recommendations:Place on aerobic conditioning programWalk on a treadmill at 3 mph and 2.5% grade 30 min, 4X/week
51Case 3: 29 year old, 61.5 kg female cyclist Wants to 50 k bike time by 15 minVO2max = 50 ml/kg/min or ~212 Watts or 3.5 Watts/kg; LT at 2.5 Watts/kgPeak Power = 410 Watts or 6.7 Watts/kgLT = 71.4% of VO2maxPossible Recommendations:mile repeats between LT and max3 X 8 min all out with min recovery
52What tests would you want? Case 4: 18 yo 50 kg female, cross country runner want to improve 5k timeWhat tests would you want?
53Case 5: 49 yo 80 kg male wants to improve marathon time What tests results would you want?
54SummaryCertain physiologic measures are good indicators of performanceMany performance tests can be conductedMultiple variations of training programs can be devised to improve performanceAll energy systems should be trained.