Acute and Early Chronic Responses to Resistance Exercise Using Flywheel or Weights

..................................................................................................................... IV SAMMANDRAG............................................................................................................VI LIST OF PAPERS ..............................................................................................................X 1. INTRODUCTION .....................................................................................................1 1.1. BACKGROUND OF RESISTANCE EXERCISE ................................................................1 1.2. CONCENTRIC AND ECCENTRIC ACTIONS ..................................................................1 1.3. ACUTE RESPONSES TO RESISTANCE EXERCISE .........................................................2 1.3.1. Motor unit recruitment and muscle use assessed by EMG and functional MRI.................................................................................................................2 1.3.2. Neuromuscular fatigue ...................................................................................3 1.3.3. Cellular signalling for muscle hypertrophy....................................................3 1.4. EARLY CHRONIC RESPONSES TO RESISTANCE TRAINING..........................................4 1.4.1. Strength and neural adaptations ....................................................................4 1.4.2. Hypertrophy ...................................................................................................4 1.5. LOADING DURING RESISTANCE EXERCISE................................................................5 1.5.1. Loading during weight training......................................................................5 1.5.1. Loading during flywheel training...................................................................5 3. AIMS AND HYPOTHESES .....................................................................................7 3.1. AIMS .......................................................................................................................7 3.2. HYPOTHESES...........................................................................................................7 4. METHODS..................................................................................................................8 4.1. SUBJECTS ................................................................................................................8 4.2. STUDY DESIGN, TEST AND TRAINING PROTOCOL .....................................................8 4.3. RESISTANCE EXERCISE DEVICES, FORCE AND KNEE JOINT ANGLE..........................13 4.3.1. Flywheel training devices.............................................................................13 4.3.2. Weight training devices ................................................................................15 4.4. ELECTROMYOGRAPHY ..........................................................................................17 4.4.1. Multichannel EMG.......................................................................................17 4.4.2. Bipolar EMG................................................................................................18 4.5. MAGNETIC RESONANCE IMAGING.........................................................................19 4.5.1. MRI for assessment of muscle volume..........................................................19