Muscle Soreness A. Acute 1. Shortness shortly after exercise 2. Reasons a. Ischemia (lack of O2) (1) lack of blood flow (2) muscle works anaerobically (3) build up of LA b. Electrolyte imbalance (Na and K) c. Edema (swelling of the tissue from fluid) (1) capillaries are permeable to fluids from the blood (2) when fluid oozes out of the extracellular places, it puts pressure on the nerves and causes pain d. Waste Accumulation (1) due to inadequate blood flow B. Delayed Onset Muscle Soreness - DOMS 1. Occurs 8 - 14 hours later 2. Reaches peak after 48 hours 3. Reasons for it are disagreed upon 4. Theories a. Spasm Theory - ( Devries, USC) (1) looked at EMG as a result of exercise (a) ischemia in muscle i) causes pain a) causes spasm b) causes more ischemia * if a muscle hurts, it contracts (2) Weaknesses in this theory (a) Ischemia produced is greatest during the activity (b) why then does the ischemia peak 48 hours later (c) Also, why does this occur primarily in the untrained? i) should work also in the well trained as they work till they get initial ischemia (d) Abraham tested Devries theory i) did not find the increased EMG during soreness b. Lactic Acid Theory (1) Discounted also (a) LA at the highest level at the end of the activity (b) LA is gone in 1.5 hours if is a large amount (c) Is therefore not around 48 hours later (d) Also, since LA is diffusing, it should go to the other parts of the body and create soreness there also, and it does not c. Eccentric Contractions (1) All research seems to agree that eccentric cont. cause more muscle soreness (2) Research study (a) Treadmill running i) showed higher lactates and lower soreness running uphill when compared to running downhill on a treadmill (3) Recruitment theory (EMG proven) (a) Concentric contractions recruit a large amount muscle fibers to do its work i) therefore, each muscle fiber does not have to work maximally since there are many muscle fibers recruited (b) Eccentric contractions constantly lessen the amount of muscle fibers used. i) This puts more strain on each muscle fiber, causing each to work harder. d. Tissue Edema theory (1) Tissue edema may put pressure on nerves and cause pain. (2) This also should cause soreness immediately and not later, though. e. Damaged muscle theory (Huff 1902) (1) Tested many times by: (a) looking at the amount of myoglobin in the urea (myoglobinurea) (b) if the muscle is damaged, i) myoglobin is released from the muscle ii) leaves blood into the urine (c) high correlation between soreness and myoglobin in urine (2) Abraham studied this and disagreed (a) stated that there was no correlation (b) he suggested that with exercise the permeability of the membrane changed (3) Creatine Kinease was then used for testing (a) this remains in the muscle cell unless the cell membrane is damaged (b) to look for tissue damage, look for high lecels of creatine kinease (is also used in checking the severity of heart attacks) (c) The problem is that people who exercise regularly have high resting levels of creatine kinease (d) These high levels may take as much as 12 weeks to subside (after a long exercise such as a marathon) (e) Also, if one exercises with a high CK level it will take even longer for it to diminish. f. Connective Tissue Damage Theory (1) Hydroxyproline (OHP) is released into the blood as a result of CT damage (a) it is also excreated by the kidneys (2) Abraham found peak levels of OHP to be around when peak levels of soreness ocurred g. Eccentric Contractions (1) tend to wear out muscle and CT h. Starting and Stopping (1) Activities with large amounts of this produced soreness also i. Stretching (1) Static (a) Causes less soreness i) ballistic stretching uses the "stretch reflex" to stop the motion. It is believed that this is an eccentric contraction, and this leads to soreness. C. Prevention and treatment of muscle soreness 1. Prevention a. Warm up sufficiently prior to the exercise (1) gradually increase the temperature of the muscle, tendons, and the joint. (2) increases in temp. decrease the viscosity within and outside the joint, and also in the CT b. Following the activity, warm down is the reverse of the warm up. (1) keeps blood flow high (a) gets rid of metabolic wastes (b) helps reduce the # of edema 2. Treatment a. Static Stretching (1) the stretching causes electrical activity that causes relaxation b. Do the same activity again (while still sore) but to a lesser degree (1) uses the same tissues and CT that are sore (2) stretches the muscle and increases the blood flow there c. Heat works but penetrates slowly (1) (whirlpool avg. temp is 110) d. Ben Gay (1) Doesn't penetrate deep (2) doesn't heat, instead irritates the skin much as a chili pepper does e. Massage (1) May work as it stimulates blood flow (2) May also cause more soreness as those muscles need rest to recover I. General Principles of training A. Regulate the intervals of training 1. Depend on the reason for training a. athlete, burn cal's, etc. 2. One way to measure is to moniter HR (1) Need O2 to muscle a. Maximal HR (1) Male (max. HR = 220 - age) (2) Female (max. HR = 226 - age) b. Heart rate range (1) MHR - RHR = HRR max - rest= range (2) % of MHR depends on the reason for the training (a) threshold level for training effect is 75 %. c. Karvonins Formula (1) THR = ((MHR - RHR) * .60) + RHR T = training (2) This formula may need to be adjusted at the % to fit the proper HR. This seems like a somewhat useless formula then. 3. Anaerobic Threshold a. Ways to determine (1) by ventilatory measures, referred to as "ventilatory threshold" (a) measure respiratory phenomenom i) look at the intensity of the exercise ii) relate it to MVV iii) relate MVV to VO2max iv) relate CO2 to VO2max (b) problem arises when trying to determine the exact point where the break occurs. Instead of seeing a sharp point, will probably see a curve. i) To get around this, possible plot 2 factors vertically vs. 1 horizontally (2) OBLA (onset of blood lactate accumulation) (a) it's a more accurate way than resp. but it also has pitfalls (b) 1 millimole of lactate present at rest (c) At about 4 mm, the increased production of lactate increases dramatically (d) this is an indication of AT b. Significance (1) To get an idea of workload intensity (a) work too hard - lactate (b) work too easy - no effect (2) Its important as an indicator of speed (a) if two subjects have the same VO2 max, the subject with the higher AT will probably win (b) running economy is also a factor i) determined by measuring l/min of O2 consumption at a set mph against a standard c. Text suggests (1) To reach AT (a) 85 % of MHH .or. (b) 80 % of HRR