Lecture 6 Flashcards
Physiological adaptations to training are largely dependent on…
The “training impulse” (i.e. training volume or overload)
External training load =
Physical output: distance covered, intensity, reps (mechanical work)
Internal training load =
Physiological effect that occurs: HR, biochemical/hormonal response, muscle damage markers
Endurance training
Repeated sessions of continuous, dynamic exercise performed against a moderate workload (60-80% vo2max) for an extended period of time (10min-hours)
Strength training:
Repeated sessions of very brief, intermittent ex performed against a heavy resistance that is usually characterised as a relatively high % of the workload that can be lifted in a single, maximal effort (1RM). A single effort lasts up to several seconds and is repeated several times with minimal rest within a set, and several sets performed with a few minutes rest between sets.
Sprint training:
Repeated sessions of relatively brief, intermittent dynamic ex often performed with all out effort or at intensity which elicits maximal or supramaximal aerobic power (>90%vo2max). last from few seconds to several mins, repeated several time w/ few mins rest/low intensity ex in b/w efforts.
Can you run faster than your vo2max?
yes
Scientific context
Simple interventions employed in lab studies
Removed from complex, periodised strategies norm for competitive athletes
Likelihood of establishing cause and effect (simple design)
Coaching context
Complex training interventions formulated to elicit greatest improvement in performance.
This is regardless of the precise mechanism(s) involved, which can include variables that are not readily explained by physiological changes (mood, motivation).
*The capacity to do work ultimately depends on…
The rate and efficiency at which chemical energy can be converted into mechanical energy for skeletal muscle contraction
What factors contribute to successful performance?
Ability to do work or generate power = major determinant of performance in many sports
Effective program design and monitoring requires ability to measure power and use data in performance analysis
Bioenergentics =
Flow of energy within a living system
-extract energy from macronutrients and transfer energy at the rate required to the contractile elements of skeletal muscle
Irrespective of the rate or type of biological work performed…
All forms of biological work require power generated from transfer of chemical energy
The choice of energy system used is influenced by:
1 supply velocity/demand
2 availability
3 oxygen supply
ATP and PCr during sprinting
Reduction/decreased regeneration of PCr, not ATP, is limiting factor
ATP-PCr summary:
Oxygen – no PCr to Cr ATP formed/s – 10 APT formed/molecule of substrate 1 Available capacity - <15s
Glycolysis summary:
Oxygen – no Glucose of glycogen to lactate ATP formed/s – 5 APT formed/molecule of substrate 2-3 Available capacity - ~1min
Oxidative CHO summary
Oxygen – yes Glucose of glycogen to CO2 and H20 ATP formed/s – 2.5 APT formed/molecule of substrate 36-39 Available capacity - ~90min
Oxidative lipid summary:
Oxygen – yes FFA to CO2 and H2O ATP formed/s – 1.5 APT formed/molecule of substrate >100 Available capacity – days
Training can improve ex capacity through:
- altering rates of energy provision from both non-oxidative and oxidative sources
- maintaining tighter metabolic control through a closer matching b/w rates of ATP hydrolysis and synthesis
- improving fatigue resistance
- increasing economy of motion
Increase in oxidative capacity of skeletal muscle via:
1 morpholigical changes i.e. increased mitochrondrial volume density
2 biochemical changes: i.e. increase in total protein content
3 biochemical changes: i.e. increase in maximal activity of various mitochondrial enzymes
Mitochrondrial volume density:
Increases relatively quickly by endur training in the 3 muscle fibre types in mixed muscle, provided the intensity is sufficient to recruit all motor units
Mitochrondria:
Located around periphery of myofibers ten to be greater in extent after training as compared to those located closer to the centre of the fiber.
Improved respiratory control sensitivity =
Increased mitochrondrial content reduces the rate of o2 and substrate flux per indv mitochondrion – thus a lower [free ATP] is needed to activate cellular respiration to achieve a given rate of ATP formation
Increased mitochrondrial content:
Reduced rate of CHO utilization & increase capacity for LIPox at given submaximal intensity
Classical exercise physiology findings:
Capillarisation
Muscle enzyme activities
Fibre phenotypes and size
Endurance training adaptation =
Fatigue resistant
Resistance training adaptation =
Increased muscle strength and size
Aerobic system changes with training – ventilation-aeroation
Minute ventilation Ventilation:perfusion ration O2 diffusion capacity Hb-o2 affinity Arterial o2 saturation
Aerobic system changes w/ training – active muscle metabolism
Enzymes and oxidative potential Energy stores and substrate availability Myoglobin concentration Mitochondria size & # Active muscle mass Muscle fiber type
Aerobic system changes w/ training – central blood flow
Q (HR, SV)
Arterial BP
O2 transport capacity [Hb]
Aerobic system changes w/ training – peripheral blood flow
Flow to nonactive regions Arterial vascular reactivity Muscle blood flow Muscle capillary density O2 diffusion Muscle vascular conductance O2 extraction Hb-o2 affinity Venous compliance and reactivity
Heart dimensions and training
Aerobic = bigger ventricular chamber – proportional increase in wall thickness RT = unchanged chamber volume – thicker ventricular wall
HR response in relation to vo2
Increases parasympathetic activity & small decrease in sympathetic discharge
SV increased during rest and ex w/ training because of
1 increase in internal left ventricular vol (due to plasma vol expansion & mass)
2 reduced cardiac stiffness
3 increased diastolid filling time (due to Bradycardia)
4 improved cardiac contractile function
Anaerobic adaptations to training:
Increase quantity and activity of key enzymes that control the anaerobic phase of glucose metabolism
Increase capacity to generate high levels of blood lactate during all-out ex
1 increased levels of glycogen & glycolytic enzymes
2 improved motivation and “pain” tolerance to fatiguing ex
