--- module: 104-02 language: en chapter: 104 title: "Exercise, Adaptation, Thermoregulation, Altitude, and Extreme Environments" module_title: "Training adaptation, fatigue, recovery, and performance" source_sha256: 5dcc0627b47988a9625c7f7f7b1dc8bbc8346d18403ef57018d0f4a078c02841 --- # Training adaptation, fatigue, and recovery ## Training principles ### Stimulus exceeds accustomed demand ### Recovery permits remodelling ### Specificity, with transfer via shared limits ### Progressive overload as capacity grows ### Variation spares repeatedly stressed tissues ### Reversibility when stimulus is removed ### Balance of signal and recoverable cost ## Signals to adaptation ### Bout alters calcium, energy, redox, tension ### Kinases, transcription, protein synthesis ### Early molecular response is not proof #### Repeated bouts must accumulate ### Novice stimulus may be expert maintenance ## Endurance and interval training ### Mitochondria, capillaries, fat oxidation ### Lactate transport, plasma volume, autonomic efficiency ### Larger stroke volume lowers submaximal heart rate ### Maximal uptake: central delivery, peripheral extraction ### Performance also via economy, threshold, glycogen ### Intervals: adaptation in less total time #### High physiological and perceptual burden #### Label alone cannot prescribe or compare ### Low-intensity volume builds tolerance and skill ## Strength, power, and eccentric work ### Early strength gains largely neural ### Hypertrophy when synthesis exceeds breakdown ### Mechanical tension as major signal #### Heavy load or light load near fatigue ### Size explains much but not all strength #### Architecture, leverage, tendon, neural control ### Power declines with age before strength #### Train with intent to move rapidly ### Eccentric: high force, low metabolic cost #### Greater initial damage when unaccustomed #### Repeated-bout effect protects ### Transfer depends on angle, velocity, range ## Connective tissue and flexibility ### Bone responds to dynamic, novel strain #### Short varied impact is osteogenic #### Continuous low strain saturates response ### Tendon adaptation may lag muscle #### Strength can outpace tissue readiness ### Cartilage needs cyclic loading within capacity ### Stretching raises tolerance as well as structure ### Intense static stretch may cut power ### Flexibility is not universally protective ## Skill and concurrent training ### External focus supports automatic control ### Variable practice improves transfer ### Fatigue changes technique and error #### Severe fatigue can reinforce unsafe patterns ### Concurrent training can blunt strength gains #### Load, modality, nutrition, session proximity ### Prioritise key quality when fatigue is low ## Load, overreaching, and soreness ### External load: work performed ### Internal load: physiological, perceptual response ### Monitoring one alone misleads ### Functional overreaching: planned dip, then gain ### Nonfunctional: longer impairment, no gain ### Overtraining syndrome: exclude other causes #### Infection, iron, energy availability, sleep ### Soreness reflects structure, not lactate #### Red flags: dark urine, swelling, weakness ## Recovery, sleep, and nutrition ### Systems recover on different timescales ### Low-intensity movement can aid comfort ### Judge strategies by meaningful outcomes ### Sleep supports learning, immunity, repair #### Extend opportunity and stabilise timing ### Protein spread, but daily total central ### Match carbohydrate availability to demand ### Low energy availability harms many systems ### Pre-exercise overdrinking raises hyponatraemia risk ### Supplements: mechanism, dose, contamination ## Injury and periodisation ### Tissue capacity interacts with load and chance ### No single ratio predicts all injury ### Pain and imaging imperfectly track damage ### Exclude serious pathology, restore function ### Complete rest reduces capacity ### Plans adapt to measured response ### Goal, limits, minimal stimulus, monitor, revise