Cardiorespiratory Endurance Training

• This lecture is about cardiorespiratory endurance, and ways to prescribe training for populations
• Stretching may be a common practice, it does not correlate with prevention of injuries, according to a systematic review of literature.
• Strength training, increases the tensile strength of muscles and tendons, and is the best protection against muscle strains.

Indicators of performance for Cardiorespiratory endurance Training

• Prescriptions for populations
• VO2 max, lactate threshold, and economy, are all indicators of performance
• Adaptations and trainability (time course and mechanisms)
• Synergistic effect of training, as well as aerobic training prescriptions

Understanding Cardiovascular Endurance

• Regular and progressive activity that is dynamic in nature is key
• Involves a substantial portion of musculature, such as cycling, rowing, running, skating, etc
• Energy is coming from oxidative phosphorylation.
• Training leads to morphological and biochemical adaptations that increase one or more indices of endurance performance
• VO2 Max is acutely trainable, and can improve quickly
• Lactate threshold is chronically trainable, and takes longer to train.
• Economy of movement is trainable, depending on what it contributes to the economy of movement

VO2 Max

• The VO2 max was "born" around 1923-25
• Archibald Vivian demonstrated that oxygen uptake increased linearly with running speed, but eventually reaches a maximum
• People have been measuring VO2 max for roughly 100 years
• The maximum rate of O2 consumption via oxidative phosphorylation during whole body, dynamic exercise
• High plasticity, can change and is flexible, and take only minutes to attain
• Cannot be sustained indefinitely, as it increases with activity/training, but declines with inactivity and age Forms of Expression:
• Expressed in Liters/min (absolute)
• Expressed in ml/kg/min (relative)
• A rate not a capacity: pros and cons (rate of oxygen consumption / minute)
• Absolute makes it better to compare two people
• The bigger person - between two people with the same fitness levels will have a larger v02 max
• Relative allows comparison of individuals

VO2 Max Cont.

• Large inter individual differences exist, because different people have two different VO2 maxes
• Genetics vs training? It's very hard to determine why someone has the VO2 max
• Could be fitness and training but also due to genetics and their genetic makeup.
• Very reliable laboratory measure; score is very specific to test.
• Relative V02 max indicate performance limitation
• Relative VO2 Max scores vary among athletes

VO2 max scores

• High score ever recorded 98-99 ml/kg/min in a cyclist
• Female elite score = joan benoit, and may be limited by size
• Cross country skiers have the highest values, and more of their musculature is needed than runners.
• Therefore, O2 needs to be replaced and replenished.
• A good score is typically a combination of both training and genetics
• Age dependent decline in VO2 max - 5-10% per decade
• Males typically have a larger peak score due to size

VO2 Max Normatives

• Relative scores between men and women - men typically have better VO2 max and cardiovascular fitness.
• Scores are dynamic change for what is a good score - baseline score based on age.
• Animal vo2 max is related to animal size
• 180 ml/kg/min - horses
• 240 ml/kg/min - dogs
• Typical increase is 25% within 10-15 weeks of training Range: 0-100%, Greatest increase observed in untrained or clinical populations, while Smallest increase observed in trained populations
• After several months of training, VO2 max may not increase further
• Central adaptations occur more quickly than peripheral adaptations. Q = cardiac output
• Endurance training and maximal oxygen consumption with ageing relates to the role of maximal cardiac output and oxygen extraction
• VO2 max increase can be attributed to the increase in Qmax, or increase in AVO2 delta (central vs peripheral)
• Metal analysis on 16 studies (cutoff may 2015) took place between 8-52 weeks endurance training

More factors for VO2 Max

• Training induced increased Qmax correlates with increased VO2 max across lifespan
• Training induced increase AVO2 delta possible, but took >12 weeks training, It showed a high correlation with pre-training Qmax.
• Performance and VO2 max are not always related at a rate of one to one
• The lactate threshold is the exercise intensity corresponding to rapid increase in blood lactate during whole body, dynamic exercise
• The lactate threshold is the intensity corresponding to onset of blood lactate accumulation during progressive whole body, dynamic exercise
• Expressed as %vo2 max or % max HR, this represents the highest percentage of VO2 max that can be sustained
• May be most important performance parameter, but less reliable measure than VO2 max
• The single most important factor for endurance, but a less reliable laboratory measure than VO2 max.
• Trainable but responds more slowly than VO2 max
• Untrained - at near 40-50% vo2 max
• Trained - at 50-70% vo2 max
• Superior >70% vo2 max

Lactate Threshold and adaptations

• Reflects adaptations in peripheral physiology, due to increase AVO2 delta
• Continues to increase after VO2 max has plateaued.
• Even if VO2 max does not increase this change will increase submaximal performance
• The longer you can delay blood lactate the fitter you are.
• LT can increase relative to VO2 max with extended training
• Speed at LT is most important performance parameter
• the training induced increase in LT is that which most increase endurance performance

Running Economy Factors

• Running economy refers to the energy demand for a given velocity of running
• Determined by steady state VO2 vs speed, and expressed in ml/kg/vel
• VO2 max is like the gas tank in a car, but running economy is like the mileage on the car
• Higher economy relates to a lower VO2 for a given speed (assuming same mass), related to biomechanics of gait and or viscoelatic properties of muscles
• Long distance runners have tend to have most economical gaits, that peaks at 6-12 mph, but can be related as cause or effect
• Folland et al. (2017) study found a relationship between kinematics and running economy, where n = 97 (50 ♂ 47 ♀) at various levels
• Performed discontinuous treadmill running in 4-min stages with speed increase of 1 km hr-1 until LT
• Measured 3-dimensional full-body kinematics and VO2 at 10 - 12 km hr-1
• derived energy cost at the highest common LT
• 3 kinematic variables explained 39% of variability in economy
• Vertical oscillation
• Minimum knee joint angle, is the knee angle is during ground contact
• Minimum horizontal pelvis velocity

Running Economy Explained

• Strive performance
• With gait training, you can become more efficient.
• The better the economy - the more efficient you get, and you can train VO2 max all you want but you should also train gait to improve
• You need the right foot placement, body placement, and aspect ratio to have a better running economy and improve vo2 max
• FITT factors interact and changes in intensity will change volume requirements and vice versa
• Increased frequency of training can incur greatly increased risk of injury and overtraining
• The general population only need 30 - 90 minutes of working out to see adaptations
• VO2 Max adapts quickly, but other indices adapt more slowly
• Central and peripheral adaptations directly affect VO2 Max, while peripheral adaptations can change lactate threshold

Training Prescriptions

• Intensity is the most important variable
• Training effect proportional to training intensity
• optimal training for general population differs from athletes in quality instead of quantity vs specificity Typical Objectives: ↑ Fitness ↑ Health morbidity, Obesity,↓ BMI,↓ WC,↓ BP,↓ BLs F = 3-4 per week I = 60-85% MHR T = 30-90 min T = does it matter?
• For Continuous Training
• Always a duration x intensity trade off, with a linear relationship between intensity and CRE adaptations
• Competitive athletes require increased↑ training intensity, since its the best way to ensure specificity and progress training load

Types of Training

• The difference between continuous (LSD) training which provides volume, not intensity and discontinuous (fartlek, intervals) which provide intensity stems from their intensity and volume combinations
• Intensity is most important training variable
• High intensity eliminates non-responders
• Training effect proportional to training intensity
• Training can create increased oxidative potential and lower fatiguability = a key training adaptation
• Discontinuous training allows for repeated bouts of high intensity exercise: Interval vs intermittent Provides high intensity Provides critical volume Most efficacious training method
• For maximal aerobic adaptations: long work (up to 5 minutes) with work to rest ratios of (1:1) By recruiting type 2 x fibers Increased oxidative capacity and decreased fatigability Also displace hypertrophy Also increased metabolic load

More on Training Types

• Intensity targets type 2x fibers, since these adaptations do not occur at lower intensities because type 2 x not recruited
• Hickson et al. (1977) Linear increase in aerobic power induced by a strenuous program of endurance exercise
• Bacon et al. (2013) VO2 Max Trainability and HIIT Meta Analysis
• Do non responders exist because CAT is low intensity? Examined studies using IT and IT + CAT (from 1965 - 2012)
• Studies lasted 6 - 13 weeks
• No non responders found!
• Sprint interval training (SIT) as a Novel model using supramaximal cycling Typical SIT results Increased performance

This lecture discusses cardiorespiratory endurance, training prescriptions for various populations, and indicators of performance. It covers VO2 max, lactate threshold, economy, adaptations, and trainability. Strength training increases muscle and tendon tensile strength, offering the best defense against muscle strains.