Muscle pain and fatigue.pdf

Centre for Exercise Science and Sports Medicine, FIFA Medical Centre of Excellence School of Therapeutic sciences, Faculty of Health Sciences, University of the Witwatersrand Johannesburg Muscle pain and fatigue Aim Learn what causes muscle soreness and how to prevent it. Objectives To in...

Centre for Exercise Science and Sports Medicine, FIFA Medical Centre of Excellence School of Therapeutic sciences, Faculty of Health Sciences, University of the Witwatersrand Johannesburg Muscle pain and fatigue Aim Learn what causes muscle soreness and how to prevent it. Objectives To investigate the following concepts: 1. Acute muscle soreness 2. DOMS 3. Exercise Induced muscle soreness 4. Muscle fatigue 5. Stich Acute Muscle Soreness Accumulation of the end products Pain that occurs during activity Possible Explanation: Ischemia The effects ò forceful weight training Impedes movement ò waste products Stimulate the sensitive nerve endings. Movement ò fluids out ò the capilleries causes swelling, resulting in pain. Exercise induced cramps Exercise induced muscle cramps During the height of competition, immediately after comp, or at night in the deep of sleep. Frustrating phenomenon Most ex-induced muscle cramps are unrelated to disease or medical disorder. Symptoms: painful, spasmodic, involuntary contractions of skeletal muscles that occur during or immediately after ex. Nocturnal musc cramps may or may not be associated with ex. Treatment of Exercise induced muscle cramps Rest and stretcing Fluid intake Prevent EIMC’s Be well conditioned Regularly stretch Maintain fluid + electrolyte balance ↓ ex intensity and duration if necessary Delayed-Onset Muscle Soreness (DOMS) Soreness is felt 12 to 48 hours after a strenuous bout of exercise Results primarily from eccentric muscle activity Is associated with: – Structural damage – Impaired calcium homeostasis leading to necrosis – Accumulation of irritants – Increased macrophage activity May be caused by inflammatory reaction inside damaged muscles Electron Micrograph of a Muscle Sample Taken Immediately After a Marathon From R.C. Hagerman et al., 1984, "Muscle damage in marathon runners," Physician and Sportsmedicine 12: 39-48. Electron Micrograph Showing Normal Arrangement of Actin and Myosin Filaments and Z-disk Before and Immediately After a Marathon From R.C. Hagerman et al., 1984, "Muscle damage in marathon runners," Physician and Sportsmedicine 12: 39-48. 1. LA accumulation theory The building up ò LA goes hand in hand with intensive training. 2. Spasm theory DOMS is a cycle which repeats itself: Strenuous activity causes musc ischemia, leading to the accumulation ò met wastes which stimulate the nerve endings, causing pain. 3. Eccentric Contractions Talag found that the group trained solely with eccentric contractions experienced extreme musc soreness, while the isometric and concentric groups experienced little or no soreness. 4. Abraham’s Muscle Tissue Damage Theory 1979 Muscle soreness to correlate with the appeareance of myoglobin in the urine, with myoglobin being the marker ò musc fibre trauma. Armstrong’s Sequence of Events in DOMS 1. Structural damage to the muscle cell and cell membrane 2. Impaired calcium availability 3. Increased microphage activity DOMS – Who’s at risk? The weekend warrior Doing too much too soon, The less conditioned musc  Task specificity is another possible cause of DOMS even in highly conditioned athletes The change of sport Prevent DOMS Ex only within your own comfort range Avoid intense jerky movements Perform a variety of stretching exercises Be very careful when weight training. Treatment for DOMS Massage, heat, static stretching and mild ex may temporarily remove the symptoms Do not attempt to work through pain Consult your physician Muscle Fatigue Most efforts to describe underlying causes and sites of fatigue focus on: − The energy systems − The accumulation of met by products − The NS − The failure of the musc fibre’s contractile mechanism 1A. Energy Systems – PCr depletion Biopsy studies of human thigh muscle have shown that during repeated max contractions, fatigue coincides with PCr depletion. 1B. Energy Systems – Glycogen depletion Glycogen reserves are limited and are depleted quickly.  2. Accumulation of Met products Although most people believe that LA is responsible for fatigue and exhaustion in all types of ex, LA accumulates within the musc fibre only during relatively brief, highly intense muscular effort. 3. Neural Transmission Fatigue may occur at the NMJ: The release / synthesis of Ach might be reduced Cholinesterase might become hyperactive Cholinesterase activity might become hypoactive, The muscle fibre membrane might develop a higher threshold Some substances might compete with ACh for the receptors on the musc membrane K+ might leave the intracellular space of the contracting musc 4. Central Nervous System CNS also might be site of fatigue, perhaps as a protective mechanism. Perceived fatigue usually precedes physiological fatigue, and athletes who feel exhausted often can be psychologically encouraged to continue. Stitch Many athletes complain of a sharp, colicky pain in the left or right upper quadrant during strenuous exercise. Reducing Muscle Soreness 1. Reduce the eccentric component 2. Start training at a low intensity 3. Begin with a high-intensity, exhaustive bout of eccentric-action exercise Summary Acute muscle soreness occurs late in an exercise bout and during the immediate recovery period after an exercise bout Delayed-onset muscle soreness (DOMS) occurs 12 to 48 hours after exercise Occurs mostly with eccentric muscle action Causes include structural damage to muscle cells and inflammatory reactions within the muscles Muscle soreness may be an important part of maximizing the resistance training response