Exam 4

• The prescription of exercise


  an exercise prescription (E x Rx) is a natural extension of the exercise if medicine concept

  
  

  Ex Rx impact parallels medical applications of a pharmaceutical Rx

  - dose

  - effect
• Dose response relationships


  the effect (response) of the amount of a drug

  - potency- dose of exercise required to bring about the desired effect

  - slope- how much change in effect comes from a change in dose

  - maximal effect- maximal benefits achieved from exercise

  - efficacy

  - variability- effect varies between and within individuals

  - side effect

  - adverse effect
• FITT principle


  frequency- days per week, times per day

  intensity- % VO2 max, % maximal HR

  - rating of perceived exertion

  - lactate threshold

  time- number of minutes of exercise

  type- resistance, cardiovascular, endurance
• FITT-VP principle


  the addition of volume and progression to FITT

  volume- frequency x intensity x time

  progression- transition from easier to harder exercise
• Current PA guidelines


  - 150 min of moderate intensity/ week OR 75 min of vigorous aerobic activity/ week

  - 2x per week of muscle strengthening activities or 2 or more days a week that work all major muscle groups
• Moderate to vigorous physical activity is commonly abbreviated MVPA


  MET costs of various exercises, physical activities, and common activities of daily living are well described and can be prescribed according to reference materials
• Is vigorous exercise better than moderate activity?

  vigorous PA is associated with reduced risk of CHD compared to lower intensities

  - CHD risk factors also lower

  vigorous PA is more beneficial for altering CHG risk factors

  higher intensity PA associated with:

  - greater impact on CHD risk factors

  - less sick leave

  moderate intensity PA

  - 3-6 METs

  - may be vigorous for deconditioned subjects
• Prescribing exercise to improve VO2 max

  - exercise intensity refers to the overload placed on the cardiovascular system

  - because of linear relationships between intensity and HR, exercise intensity can be monitored by HR

  - heart rate reserve (HRR) and percent of VO2 reserve (VO2R)

  - HRR is the difference between resting HR and max HR

  - VO2R is the difference between resting VO2 and VO2 max

  - methods:

  - direct- measure HR during graded exercise

  - indirect- estimated HR max from formula
• Assessing VO2 max


  - graded exercise test (GXT) is optimal

  - arm ergometry can produce 70% lower compared to leg ergometry
• Estimations of VO2 max

  - can be estimated from submaximal exercise

  - HR workload relationships can be used to extrapolate VO2 max based on known estimated HR max value
• General guidelines for improving fitness

  screening

  progression

  warm up, stretch and cool down, stretch
• Exercise prescription to improve cardiorespiratory fitness (CRF)

  dynamic, large muscle activities- walking, running, swimming, etc

  2-5 x per week, 20-60 minutes, intensity 40-89% HRR or VO2R, volume of 500-1000 MET-min/ week
• Direct method


  - because the relationship between HR and VO2 is linear, HR can be used to track exercise workload intensity

  - the target HR range can be determined from maximal GXT
• Indirect method


  Karvonen's HRR method

  - subtract resting HR from max to get HRR, take 60% and 80% of HRR, ass each HRR to resting HRR to obtain THR range

  Percentage of maximal HR (HR max)

  - take 70% and 85% of max HR as THR range

  Use RPE scale in addition to HR to track exercise intensity

  - RPE 12-17 is about 40-89% HRR
• Strength and flexibility training

  muscular strength and flexibility are important components of a complete fitness program

  ACSM recommendation: dynamic exercises, done on a routine basis
• Health benefits of resistance training vs aerobic training

  
• Single vs multiple sets

  recommendations:

  - one set 8-10

  - 8-12 reps per set

  - 2-3 sessions per week

  multiple sets more effective for improving strength and mass

  single set sufficient when strength gain is not primary goal
• Advanced training guidelines


  multiple sets with variations in volume and intensity

  exhaust each muscle group 1-2 days/ week

  allow 1-2 days of rest

  HIIT
• Environmental concerns for exercise

  environmental conditions can elevate HR

  - heat/ humidity- increases blood circulation to skin

  - altitude- decreases oxygen bound to Hb

  adjust exercise intensity in adverse environments

  exercise in cold is typically safe
• Overload


  increased capacity of a system in response to training above the level to which it is accustomed

  too much leads to overtraining
• Specificity


  specific muscle involved

  specific energy system that are utilized
• Reversibility


  when training is stopped, the training effect is quickly lost
• Four pillars of effective training

  adherence- the single most important predictor of achieving fitness outcomes

  progressive overload- second most important

  individualization- take into account personal preferences, equipment availability, and other unique factors

  goal setting- setting appropriate targeted goals
• Influence of genetics


  genetics play an important role in how an individual responds to training

  - high responders vs low responders

  anaerobic capacity is more genetically determined than aerobic capacity

  - training can only improve anaerobic performance to a small degree

  dependent largely on fast (2x) fibers
• Training to improve aerobic power

  training to improve power must overload the circulatory system and stress the oxidative capacities of skeletal muscle

  
  

  3 principal training methods

  - interval training

  - long, slow distance

  - high intensity continuous exercise

  
  

  training is designed to improve:

  - VO2 max

  - lactate threshold

  - running economy
• HIIT


  characterized by

  - repeated high intensity exercise bouts- separated by brief recovery periods

  work interval

  - rest interval- light activity

  - contrasts moderate intensity continuous training (MICT)

  - training outcomes of HIIT- improved VO2 max, running economy, and lactate threshold better
• SIT


  characterized by:

  - short duration intervals interspersed with passive rest or active recovery

  - different from HIIT- performed at an intensity above VO2 max- supramaximal intensity

  - can improve VO2 max and mitochondrial density in skeletal muscle
• Measurement of peak running velocity for improved performance

  peak running velocity- highest speed that can be maintained for 5+ seconds

  peak running velocity is inversely correlated to endurance race finish times
• Long, slow distance


  - low intensity exercise: 50-65% VO2 max or 60-70% HR max

  - training duration is greater than event or competition duration

  - training improvements are based on the volume of training

  - however, short term high intensity training is better for improving VO2 max
• High intensity, continuous exercise

  - an excellent method of increasing VO2 max and lactate threshold

  - at or slight above lactate threshold

  - 80-100% VO2 max for most athletes

  - monitor intensity using HR
• Altitude training improves exercise performance at sea level


  altitude training may not always imporve performance at sea level

  - lower training intensity at altitude may result in detraining

  live high, train low

  - spend sleeping and resting time at altitude

  - increases rbc volume and oxygen transport capacity of blood

  - better performance gains compared to living and training at sea level
• Injuries and endurance training

  most injuries are a result of overtraining

  10% rule for increasing training load

  other risk factors:

  - strength and flexibility imbalance

  - footwear problems

  - malalignment

  - poor running surface

  - disease
• Training to improve anaerobic power- ATP-PC and glycolytic systems

  ATP-PC system

  - short (5-10 s), high intensity work intervals

  30-60 second rest intervals- little lactic acid is produced, so recovery is rapid

  glycolytic system

  - short (20-60 s), high intensity work intervals

  - may deplete muscle glycogen levels
• Training to improve muscular strength

  the goal of strength training is to increase maximum force and power

  strength training exercises classified as: isometric/ static, dynamic, isotonic

  variable resistance exercise- describes exercise machines
• Strength training adaptations


  increased muscle force production

  - proportional to muscle cross sectional area

  increased muscle mass

  - hypertrophy- increased muscle fiber diameter; responsible for most of the increase in muscle size

  - hyperplasia- increased number of muscle fibers
• Progressive resistance exercise


  improvements in strength via progressive overload

  - periodically increasing resistance to continue to overload the muscle

  basis for most weight training programs

  intensity based on % of 1-RM

  volume- number of repetitions, number of sets
• General strength training principles

  intensity- 8-12 RM

  number of sets for maximal strength gains

  - 2+ sets result in greater strength gains and hypertrophy

  - >10 sets not recommended

  frequency- 2-4 days/ week, 4-6 days if using "split" routines

  should involve muscles used in competition

  speed of muscle shortening similar to speeds used in events
• Free weights vs machines

  strength gains are similar following training using free weight and machines

  free weights:

  - produce greater strength gains

  - produce greater movement variability and specificity

  - force control of balance and stabilization

  disadvantages of free weights:

  - potential for injury

  proper lifting technique required

  - spotters needed
• Periodization of strength training

  -Systematic variation of volume and intensity over time

  -Achieve optimal gains in strength, power, motor performance, and/or hypertrophy (Over the course of a season, year, or career)

  -Linear periodization (Shift from high volume/low intensity to low volume/high intensity training)

  -Strength gains greater with periodized programs
• Concurrent strength and endurance training programs

  combined strength and endurance training may limit strength gains vs strength training alone

  - depends on training state of subject, volume/ frequency of training, way the two methods are integrated, endurance training more than 3 days a week