Types of Contractions/Movements Types of Contractions/Movements Type Definition Example Isotonic Force remains constant through ROM -improves motor performance Biceps curls using free weights Isometric Constant muscle length and tension that is proportional to the external load-Causes muscle hypertrophy Pushing against an immovable object Concentric Shortened muscle and tension that is proportional to the external load Biceps curl with elbow flexing Eccentric Force remains constant as muscle lengthens Most efficient method of strengthening muscle Biceps curl with elbow extending Isokinetic Muscle contracts at a constant velocity through varied resistance.-often used to objectively evaluate muscle strength during injury rehabilitation Require special machines (e.g, Cybex). Plyometric Rapid eccentric-concentric shortening Good training for sports that require power Box jumps Open chain Distal end of extremity moves freely Seated leg extensions and curls Closed chain Distal end of extremity is fixed Squats with planted foot Anaerobic vs. Aerobic Anaerobic vs. Aerobic Anaerobic Glycolytic Aerobic Energy source ATP-CP Lactic acid Oxidative phosphorylation (Krebs cycle)Glycogen and fatty acids Muscle type Type II (A, B) muscle-fast twitching Type I muscle-slow twitching Exercise duration 10 seconds of high intensity 2-3 minutes endurance Note Type IIA: aerobic and anaerobic Type IIB: primarily anaerobic, last to be recruited Low ATP yield Lactic acidosis after several minutes High yield ATP Requires O2 "Slow red ox muscles" First to be recruited Exercise Programs Definitions Periodization strength and conditioning term for planned variation in intensity and duration of a specific workout over a predefined duration of time Dynamic exercise improves cardiac output by increasing cardiac stroke volume Endurance (aerobic) Training results in changes in circulation and muscle metabolism contractile muscle adapts by increasing energy efficiency increases in mitochondrial size, number, and density increases in enzymes involved in Krebs cycle, fatty acid processing, and respiratory chain over time, increased use of fatty acids > glycogen over time, oxidative capacity of Type I, IIA, and IIB fibers increase percentage of more highly oxygenated IIA fibers increases Aerobic Threshold: level of effort at which anaerobic energy pathways become significant energy producer Anaerobic (lactate) Threshold: level of effort at which lactate production > lactate removal Strength Training typically high-load, low-repetition activities results in increased cross-sectional area of muscle due to muscle hypertrophy hyperplasia (increased number of fibers) less likely results in increased motor unit recruitment +/- improved synchronization of muscule activity maximal force production is proportional to muscle physiologic cross-sectional area adolescents can safely participate in appropriate strength training programs gains in strength largely due to improved neuromuscular activation and coordination rather than muscle hypertrophy gains for adolescents are reversible if training is discontinued Aquatic training Benefits decreases joint stress by lowering vertical component of the ground reaction force through buoyancy unique advantages in cardiorespiratory fitness when compared to land training less abrupt increases in heart rate increased oxygen consumption prevents secondary injuries to the lower limb Exercise Induced Laryngeal Obstruction (EILO) Commonly mistaken for exercise-induced bronchoconstriction in athletes Epidemiology gender - more common in females Mechanism - unknown Symptoms dyspnoea wheezing Differential diagnoses exercise-induced bronchoconstriction (EIB, or exercise-induced asthma) hyperventilation cardiac conditions Diagnosis negative bronchodilator reversibility test (with beta2-agonist) positive in EIB negative bronchoprovocation tests (e.g. methacholine challenge, mannitol challenge, eucapnic voluntary hyperventilation test) positive in EIB positive continuous laryngoscopy during exercise (CLE) Types (anatomic location) supraglottic level glottic level Treatment optimum treatment is being investigated Exercise-Induced Hematuria Epidemiology Incidence Microscopic hematuria present in 16.7 - 46.7% of athletes Macroscopic hematuria present in 3.1 - 19.2% of athletes Risk Factors Exercise intensity Posture Age Heat load Altitude Pre-existing kidney disease Pathophysiology Proposed pathophysiology of exercise-induced hematuria Bladder/kidney contusion from up and down motion Vascular spasm to kidney Presentation History Presence of hematuria correlates with increased exercise intensity Symptoms Asymptomatic Differential Urinary tract infection or Sexually transmitted infection Pyuria and dysuria Papillary necrosis Personal or family history of Sickle cell trait or disease Kidney Contusion Blunt impact to flank and flank pain Kidney Stone Dysuria and flank pain Treatment Nonoperative Cessation of exercise, repeat urinalysis in 48-72 hours Further workup indicated if: Hematuria persists >7 days after cessation of exercise Age >50 Weight training Effects on muscles increased cross-sectional area increased strength increased mitochondria increased capillary density thickened connective tissue Adult strength gains are associated with muscle hypertrophy Adolescent strength gains occur more from increased muscle firing efficiency and coordination Nutritional training Carbohydrate loading involves increasing carbohydrates three days prior to an event and decreasing physical activity to build up carbohydrates stores increases the stores of muscle glycogen to provide improved endurance, especially in events lasting > 90 minutes when the bodies normal supply of glycogen runs low best technique for athlete is to instead maintain normal diet Fluid loading and replacement magnitude of core temperature and heart rate increase accompanying work are proportional to the magnitude of water debt at the onset of exercise best technique is to replace enough water to maintain prepractice weight Fluid carbohydrate and electrolyte replacement best done with low osmolarity (< 10%) fluids of carbohydrates and electrolyties which enhances absorption in the gut glucose polymers decrease osmolarity Muscle Injury Muscles soreness caused by edema and inflammation in the connective tissue leads to increased intramuscular pressure occurs primarily in Type IIB fibers worse with unaccustomed eccentric exercise often with delayed onset: Delayed-Onset Muscle Soreness (DOMS) peaks at 24-72 hours elevated CK levels seen in serum Muscles strain occurs commonly at myotendinous junction (often during eccentric contraction which produces highest forces in skeletal muscle) pathoanatomy in inflammation followed by fibrosis Muscle contusion non-penetrating blunt injury leads to hematoma and inflammation extracellular connective tissue forms within 2 days, peaks between 5-21 days healing characterized by late scar formation, variable muscle regeneration myositis ossificans (bone formation within the muscle tissue) most apparent 4 weeks post-injury Muscle laceration (complete tear) typically occur near myotendinous junction characterized by abnormal muscle countour fragments heal by dense connective scar tissue mediated by myofibroblasts TGF-beta stimulates differentiation and proliferation of myofibroblasts regeneration and renervation: unpredictable and likely incomplete Muscle Immobilization Can result in shorter muscle position and atrophy Leads to decreased ability to generate tension and increased fatigability Results in fatty infiltration Atrophy occurs faster in muscles crossing a single joint Atrophy occurs at a non-linear rate most changes occur during initial days of disuse seen at cellular level: loss of myofibrils within the fibers related to duration of immobilization Atrophy is more prominent if immobilization occurs without tension quadriceps atrophy greater than hamstrings with knee immobilization in extension Treatment Local treatments designed to assist with soft tissue recovery or rehabilitation Goals of treatment decrease inflammation increase local blood flow increase tissue compliance Modalities include cryo or heat treatments massage ultrasound electrical stimulation Iontophoresis use of an electrical current to drive charged molecules of medicine through the skin to the deep tissues medications including steroids, local anesthetics, salicylates, and non-steroidal anti-inflammatory drugs (see table below) indications - see table below contraindications susceptibility to applied currents e.g. cardiac pacemakers hypersensitivity/allergy to drug used Iontophoresis Indication Iontophoresis Drug/Solution Hyperhydrosis Tap water, glycopyrrolate Muscle spasm Magnesium sulfate, calcium chloride Edema Hyaluronidase Adhesive conditions Iodine Inflammation Dexamethasone, hydrocortisone, prednisone, lidocaine, salicylates Calcific tendinitis Acetic acid Myositis ossificans Acetic acid Open wounds Zinc oxide, tolazoline hydrochloride