This chapter is about the bodies short and long termed response to Aerobic endurance training. Like chapter 5 on the bodies response to resistance training, there is also a pretty important discussion on the training and recovery relationship that can result in overtraining when mismanaged.

Key Items:

• Know how to calculate maximal heart rate with each method.
• Understand the different adaptations to aerobic endurance training both on a short term and long term time frame.
• Understand how to prevent overtraining syndrome.

Adaptations to Aerobic Endurance Training Programs

• Aerobic endurance training produces a lot of acute and long term responses to training. Many sports involves a basic level of cardiovascular endurance for health and recovery reasons.

Acute Responses to Aerobic Exercise

• The main functions of the cardiovascular system system during exercise are to deliver oxygen and nutrients to working muscles and to remove metabolites and waste.
• Cardiac Output - amount of blood pumped by heart in liters per minute.
• Stroke Volume - amount of blood pumped in one beat.
• Heart Rate - how fast the heart is pumping.
• End-Diastole Volume - blood that can be pumped by the left ventricle at the end of the filling phase.
• Venous Return - blood that returns to the heart.
• Frank-Starling Mechanism - the length that the fibers of the heart are stretched in related to the amount of force that they produce during contraction. Like a rubber band, the further they're stretched, they harder they produce force.
• Ejection Fraction - the fraction of the end-diastolic volume that is sent out from the heart.
• Maximal Heart Rate - the fastest your heart can beat.
• Oxygen Uptake - how much oxygen the body's tissues use.
• Maximal Oxygen Uptake - the most oxygen that you can use at the cellular level.
• Metabolic Equivalent (MET) - standardized unit of measurement, 3.5 ml of oxygen per kilogram of body weight per minute. The amount of oxygen the body consumes at rest for an average person.
• Fick Equation - another way to calculate oxygen uptake. Oxygen uptake (VO2) is equal to cardiac output times the arteriovenous oxygen difference.
• Arteriovenous Oxygen Difference - the difference between the amount of oxygen arterial an venous blood.
• Systolic Blood Pressure - the amount or pressure exerted against arterial walls when blood is forcefully sent out.
• Systole - ventricular contraction. Pumping blood from ventricles into the arteries.
• Rate-Pressure Product - an estimate of the workload on the heart. Heart rate times systolic blood pressure.
• Double Product - another term for rate-pressure product.
• Diastolic Blood Pressure - the pressure exerted against arterial walls when no blood is being forcefully sent out.
• Diastole - ventricular relaxation. Heart is allowed to fill back up with blood.
• Mean Arterial Pressure - the average amount of pressure in the arteries during the cardiac cycle.
• Vasoconstriction - the constriction of blood vessels. Increases blood pressure.
• Vasodilation - another term for vasoconstriction.
• Acute aerobic exercise decreases the amount of blood that flows through the rest of the body and increase the amount of blood supplied to skeletal muscle.
• Minute Ventilation - the amount of air breathed per minute.
• Tidal Volume - amount amount of air inhaled and exhaled per breath.
• Ventilatory Equivalent - the ratio of minute ventilation to oxygen uptake.
• Alveoli - where gas exchange happens in the lungs.
• Anatomical Dead Space - the areas in the lungs where air occupies space but, gas exchange cannot occur. Ex. Nose, Mouth and Trachea.
• Physiological Dead Space - alveoli where poor blood flow, ventilation or other problems with the alveolar surface impair gas exchange.
• Diffusion - the movement of molecules across a cell membrane. From higher to lower concentrations.
• Oxygen is carried in the blood by hemoglobin.
• Carbon dioxide is primarily removed from the body through combination with water and delivery to the lungs.
• Onset of blood lactate accumulation is the point where the body begins to show an increase in the amount of blood lactate that is being accumulated.

Chronic Adaptations to Aerobic Exercise

• Bradycardia - slower than normal heart rate. Found in well trained aerobic endurance athletes.
• Increased capillary density per unit of muscle decreases the distance that oxygen and metabolic substrates need to travel for diffusion.
• Ventilation is only moderately or unaffected by training.
• Neurologically, muscles become more synergistic in response to training in order to use less energy.
• Myoglobin - protein that transports oxygen in a cell.
• Mitochondria - cells power plant, produce ATP.
• Aerobic programs most successfully linked to stimulating bone growth are higher in intensity like running, and high intensity aerobics. Must be more intense than what the person experiences in daily activities.
• The hormone concentrations in a trained athlete are the same as untrained people at the same sub-maximal intensities.

Adaptations to Aerobic Endurance Training

• Aerobic metabolism plays an important role in human performance and is basic to all sports for recovery.
• Different sports involve different relationships with the aerobic system and must be trained appropriately.
• Interval training can produce significant results apart from stereotypical sub-maximal training methods.
• According to the text, aerobic endurance training can produce gains in aerobic power by 5-30% depending on the starting fitness level of the individual and genetics. Most adaptation occurs within a 6-12 month training period. Further increases are related to efficiency and increased lactate threshold.
• Intensity of training is one of the most important factors in improving and maintaining aerobic power.
• Aerobic endurance training often decreases the amount of relative body fat a person carries but, has little or no significant effect on fat-free mass.

External and Individual Factors Influencing Adaptations to Aerobic Endurance Training

• Hyperventilation - rapid and deep breathing.
• The body responds to the increased oxygen demands at higher altitudes by first increasing breathing rate at rest and during exercise and then by increasing tidal volume.
• Hyperoxic Breathing - breathing an oxygen-enriched gas mixture.
• Blood Doping - artificially increasing red blood cells in the body in order to try and improve athletic performance.
• Erythropoietin (EPO) - a hormone that stimulates red blood cell production.
• A person's genetic potential plays an important role in the magnitude of training adaptations that can occur. As someone gets closer to their upper limit, smaller and smaller increases will be seen.

Overtraining: Definition, Prevalence, Diagnosis and Potential Markers

• Overtraining - exceeding the ability of the athlete to recover.
• Overtraining Syndrome (OTS) - difficult to define, evaluate and fix. A chronically overtrained state that requires months to recover from.
• Overreaching - exceeding the level that a person can recover from.
• Functional Overreaching - temporarily exceeding the level that a person can recover from.
• Nonfunctional Overreaching - extreme, long term exceeding the level that a person can recover from.
• Heart rate can increase or decrease in response to overtraining syndrome.
• Decreases in the ratio of free testosterone to cortisol of more than 30% may be a potential marker of overtraining syndrome.
• Enough sleep, good nutrition and management of stress can help prevent overtraining syndrome.
• Detraining - the partial or complete loss of training adaptations in response to an insufficient stimulus.
• Tapering - the planned reduction in training volume that occurs before competition or planned recovery phase. Intensity is usually kept high.
• Aerobic endurance adaptations are the most sensitive to periods of inactivity.