Transcript muscle3
Muscular Fatigue • reduces pool of fibers available to contract and force – 1. lactate accumulation – 2. glycogen depletion • lactate accumulation – high intensity exercise – increased muscle lactate • reduces pH (acidic) – muscles fail to contract • decreases rate of energy production – lactate accumulation in FG fibers first • reduction of power – light exercise hastens removal • glycogen depletion • not the fatigue factor for high intensity work – low intensity work – depletion reflects recruitment pattern • ST - first to fatigue • FOG fibers second • FG may eventually deplete – as one fiber type is depleted the next is recruited – fibers dependent on fats for energy • decreased rate of energy production • must slow speed • fatigue before completely out of adipose tissue – repletion of glycogen • 2 days • reverse order of recruitment • ability to perform is limited by onset of fatigue • impairment of muscle function – depletion of substrate – disruption of energy production – electrolyte gradients – alteration of calcium uptake and release by SR – decrease blood flow and/or too much temperature increase in muscles Diseases • muscle strain – over-stretched muscle • increases heat (increased blood flow) • swelling from fluid accumulation • pain – rest and cold hydo-therapy – recovery time • days to weeks – test for muscle damage • CK • Exertional Rhabdomyolysis- tying up, azoturia – exercise induced damage to muscle • mild cramping to inability to move – common conditions • well conditioned horse – after day or two rest and full feed • over exercised • fluid/electrolyte imbalance- dehydration (decreased chloride and calcium) • deficiency of selenium and /or Vit E • hormonal effect – high strung – female • genetic predisposition • symptoms – stiff gait to not moving at all – if down, unable to get up – muscles of hind quarters and back most affected • shoulder muscles – muscle feel rigid; deep palpation causes pain – distressed, sweating, increased temperature, increases RR and increases HR • treatment – limit muscle damage – restore fluid and electrolytes – relaxants/pain relievers – keep warm and still • mild cases - walk • prevention – change diet – training • often reoccurs