Exercise Testing and Prescription Study Guide 3 Tony Berardi 1 Both guides attached 2 Know the metabolic equations This guide is also attached 3 Know terms for isometric eccentric concentric isokinetic isotonic muscular strength muscular endurance and flexibility Know the physiological mechanisms of how strength increases over time These are terms everyone should know at this point in exercise science Isometric means the same length so an example would be using a handgrip test or pushing against a wall The muscle is staying at the same length throughout the whole contraction Eccentric is the lengthening of the muscle So it would be the down part of a bicep curl the muscle is becoming straight Ideally this motion should be 3 4 sec Concentric is the shortening of the muscle So it would be the curl part of the bicep curl Ideally this motion should be 2 3 sec Isokinetic means the same velocity The only machines that produce this motion are therapy machines and are very expensive Isotonic means the same tension So free weights would be called isotonic the Muscular strength is the maximum force you can produce It s your 1 RM Muscular endurance is the ability for your muscles to lift at submaximal about for tension does not change an extended duration Flexibility is simply the ability to move your muscle through it ROM Once an individual starts a workout program they undergo neural adaptations for the first few weeks This is the body increasing the number of motor units recruited synchronization of them and increasing their firing rate So no real hypertrophy happens in those first few weeks Then after that period hypertrophy starts and one increases their lean body mass This is why some people don t get results when they work out They lift for a few weeks and don t see any results but they are gaining neural adaptations so they stop before the hypertrophy starts 4 Know conduction blocks First Degree Second Degree Mobitz Type I or Wenckebach Block Mobitz Type II Third Degree Heart Block Conduction block occurs when the electrical signal gets delayed at some point in the heart In different conduction blocks the signal is delayed at different parts of the heart Blocks can occur anywhere but it is more likely to happen in the AV node or in the bundle branches First degree block occurs when the PR interval is greater than 0 2 sec So the signal is taking a delayed time to reach the ventricles meaning the signal is delayed at the AV node It spreads from the sinus node normally and then something slows it down at the AV node This delay will slow the PR interval down So technically it s not a block just a delay in conduction It is not a concern but could be an early sign of disease of the conduction system Second degree block is when every signal does not produce a contraction Meaning some pulses make it through the AV node and some don t So for every P wave you might not have a QRS wave There are two types of second degree block Wenckebach block is a block in the AV node just like first degree block The difference is the PR interval gets more delayed with every beat because there is a variable block Eventually one signal doesn t not make it through so you will have a dropped beat P wave with no QRS and after the cycle will repeat Since it is in the AV node it will probably not progress to third degree block meaning it is benign usually Mobitz block is a block below the AV node Unlike wenckebach the delay is not variable but there are still dropped beats So you will have normal PR intervals for a couple beats then a dropped beat will occur This is far more serious than wenckebach because it is below the AV node and closer to the ventricles It is more likely to progress to third degree block very bad Third degree block is bad This means that no atrial signals are making it through the AV node to the ventricles If you remember everything about the arrhythmias if no atrial signals are making it to the ventricles there is no contraction so they will enter aystole if no other action occurs The pacemaker in the ventricles will take over but this fire very slowly and these are the start of those ventricular arrhythmias we went over The atria are still contracting but the signal is stopped at the AV node and the ventricles are also contracting The both are contracting separately because the SA node fires at 60 100 BPM and the ventricles at 30 45 so the P wave and the QRS complexes are occurring randomly PVC s are seen since the ventricle pacemaker is firing This is almost always from a degenerative conduction problem or from an MI The patient needs a pacemaker to correct conduction 5 Know what the right and left bundle branch blocks look like Know characteristics Bundle blocks occur in the left and right bundle branches so they affect conduction of the signal to the left and right ventricles respectively So since the conduction is messed up with the ventricles the QRS complex will be wide or have a weird shape For the right bundle block the right ventricle receives the signal after the left ventricle has already contracted The QRS will be wide and there will be distinct notch in the complex in leads V1 and V2 since these overlie the right ventricle There will also be a deep S wave in the leads that overlie the left ventricle leads 1 V5 V6 aVL because the late right ventricle changes the signal In left bundle block the left ventricle is depolarizing late The QRS will be wide of course and the leads over the left ventricle I V5 V6 aVL will have an altered shape Since conduction is delayed in this leads the R wave will be prolonged so instead of the sharp spike it normally has it will be round since it is wider Repolarization is also affected So you might have ST depression and T wave inversion Right bundle branch is not severe and is usually benign the right ventricle isn t really important but left bundle branch is always bad since this ventricle pumps blood to the whole body Sometimes the blocks only occur when the heart hits a certain rate and this is called the critical rate 6 Know all of the arrhythmias including the two pre excitation conditions and the stages of a myocardial infarction Know how to diagnose a Myocardial Infarction What tests do we do We went over the conduction blocks where the signal is delayed more than usual but it also be conducted too quickly There are two possible pre excitation conditions o In wolf parkingsons white WPW there is a shortcut that bypasses the AV node so the
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