HK 100 Exam 1 with correct Answers 2024/25

motor unit - ANS-A motor neuron and all of the nerve and muscle fibers it innervates; controls muscle fibers within a muscle sacromere - ANS-Basic contracting unit of muscle cell consists of actin and myosin filaments between z-lines in a muscle cell delayed onset muscle soreness - ANS-Pain or discomfort often felt 24 to 72 hours after intense exercise or unaccustomed physical activity (DOMS) concentric - ANS-when muscle fibers are shortening (Ceiling)(flexion) eccentric - ANS-when muscle fibers lengthen (Earth)(extension) isometric - ANS-when muscle fibers tense (tension) but no actual movement (In between) sliding filament hypothesis - ANS-thin filaments slide over thick filaments, shortening the sarcomere cross-bridge hypothesis - ANS-muscle contraction states how force is produced, and how the filaments actin and myosin are moved relative to each other to produce muscle shortening Electromyography (EMG) - ANS-the electrical recording of muscle activity myosin - ANS-thick filament (in A-band) actin - ANS-thin filaments first step of muscle contraction - ANS-in the neuromuscular junction, a chemical is released from the end of the nerve fiber, which causes a rapid change in voltage in the muscle second step of muscle contraction - ANS-the electrical signal travels over the surface of, and along, the muscle fibers third step of muscle contraction - ANS-the electrical signal causes the release of calcium ions into the cytoplasm (intracellular fluid( of the muscle fiber. this i san important part of the process because it is the line between excitation and contraction) fourth step of muscle contraction - ANS-the calcium ions expose active sites on the actin (thin) myofilaments, to which the myosin filaments immediately attach final step of muscle contraction - ANS-because of these attachments (cross-bridges), each myosin filament pulls the actin filaments that overlap with it at either end toward its center, producing cross-bridge cycling, which is the mechanical response to the electrical signal - ANS-number of muscle fibers per motor unit? transduction - ANS-conversion of one form of energy into another. ATP - ANS-(adenosine triphosphate) main energy source that cells use for most of their work phsophagen - ANS-Substrate : ATP, PCr, or glucose Relative Rate for ATP Production : VERY FAST Duration of Maximal Pace : 0-30 secs. Limiting Factors : PCr depletion Ex. Activities : power or weight lifting, short sprints, jumping, throwing anaerobic glycolytic - ANS-Substrate : Glycogen or Glucose Relative Rate for ATP Production : FAST Duration of Maximal Pace : 20-180 secs. Limiting Factors : lactic acid accumination Ex. Activities : longer sprints, middle-distance team sports, ball games oxidative - ANS-Substrate : glycogen, fat, or protein Relative Rate for ATP Production : SLOWER Duration of Maximal Pace : >3 min. Limiting Factors : glycogen depletion Ex. Activities : endurance events. team sports, ball games Pcr - ANS-phosphocreatine carbs, fats, proteins - ANS-resynthesizes ATP by being broken down to releases energy from chemical bonds aerobic power - ANS-rate at which long-term oxygen demand is met; influenced by GENETICS (40-50% of VO2 max) and training can increase VO2 max anaerobic power - ANS-the rate at which a person's body can meet the demand for short-term, intense activity 10 sec. sprint - ANS-53% Phosphagen 44% Anaerobic Glycolysis 3% Oxidative 30 sec. sprint - ANS-23% Phosphagen 49% Anaerobic Glycolysis 28% Oxidative carbs - ANS-= anaerobic or aerobic anaerobic - ANS-without oxygen aerobic - ANS-requires oxygen fats and proteins - ANS-only aerobic fatty acids - ANS-rest and low intensity glucose - ANS-max use proteins - ANS-most (20%) during extremely long exercise (hours) fasicle - ANS-bundle of muscle fibers muscle fibers - ANS-consists of muscle myofibrils myrofibrils - ANS-consists of repeating sacromeres - ANS-is there a "protective phase" involving muscle so you can't tear muscle and can biomechanics - ANS-the science of physical principles applied to biological systems; study of how the skeletal and musculature systems work under different conditions kinematics - ANS-description of the temporal and spatial components of movement; motion description; describing movement kinetics - ANS-the study of the forces acting on an objects causes of motion; everything to do with force temporal - ANS-= timing spacial - ANS-= moment in space improvement on performance and prevention/treatment of injury - ANS-why do we study biomechanics? father of biomechanics - ANS-alfonzo borelli broke the broad idea of biomechanics down. what do we call him? DeVinci - ANS-may have contributed to the broad ideas in the beginning of biomechanics marey and muybridge - ANS-used film to record/ analyze movement; beginning of using film to study movement; started by them talking at a bar about 'biomechanics' of a horse (19th century) motion - ANS-object changing its position in space over a period of time; a component of kinematics distance - ANS-how far an object moves; works together with speed; a component of kinematics speed - ANS-how fast an object travels; s=d/t velocity - ANS-how fast the object moves in a particular direction (DISPLACEMENT) acceleration - ANS-rate at which an object changes it velocity; a=Vf-Vi/V^ force - ANS-push or pull exerted by one object on another magnitude - ANS-large or small; characteristic of force direction - ANS-push forward, pull backward, up, down, and combo; characteristic of force point of application - ANS-where applied on an object; characteristic of force line of action - ANS-pass via line of axis of rotation; ex. kick center of a soccer ball, it has no rotation / kick the side of the ball, it has rotation; characteristic of force law of inertia - ANS-a body at rest or in motion continues in that state unless acted upon by an outside and unbalanced force gravity - ANS-a force of attraction between two objects that is due to their masses. law of acceleration - ANS-acceleration of an object is dependent upon (a) the net force (b) the mass of the object; a = F/m law of action-reaction - ANS-for every action there's an equal/opposite reaction impulse-momentum relationship - ANS-relationship of force and muscle; impulse-product of force and duration of time force is applied (mac impacts momentum); momentum - mass in motion (mass x velocity); Ft = ^mV = impulse causes a change in momentum (ex. egg drop) size of the pull - ANS-affected by mass of objects and distance between them; involves gravity center of mass - ANS-point about which the weight is symmetrical; = bellybutton when standing still; CAN BE OUTSIDE OF THE BODY women - ANS-who has a lower center of mass and therefore has better sense of balance? contact force - ANS-when two bodies physically touch either ground reaction force - ANS-force exerted on athlete by ground; affects motion (up, down, forward, backward, and side-to-side); if this wasn't pushing up, we wouldn't be able to stand. but we can manipulate it by our body movement vertical jump - ANS-vertical GRF long jump - ANS-vertical (up) and horizontal (forward) GRF when you are landing and trying to force yourself to stop, this causes your force to go below 0 because you are fighting force - ANS-why in horizontal jump, does the data go below 0? shock attenuation in running shoes - ANS-softness is the worst for your feet because the force will just break right through the padding; firm is too hard; midpoint is where you want the padding in your shoes; this refers to? fosbury flop - ANS-common technique of high jump. Ends with the athlete landing on their upper back; this is better than the use-to-be straddle technique because your center of mass shifts outside of your body and you don't have to work as hard to get your whole body over the bar friction - ANS-a force that opposes motion between two surfaces that are in contact (parallel to the surface that resists movement); common terms used for friction : grip or traction maximum limiting friction - ANS-point to where friction can't increase anymore slipping - ANS-propelling force > friction force - nature of surfaces contact - size of force holding surfaces together - ANS-factors that affect the size of friction normal force - ANS-acts perpendicular to surfaces, pushes the objects together (opposes friction) coefficient of friction - ANS-ratio of friction force to normal force (> normal force) ex. tires tire thickness - ANS-thicker = more friction inflation pressure - ANS-less air = more friction wheel diameter - ANS-small tire = more friction surface - ANS-rough = more friction fluid force - ANS-force put on an object as it moves via fluid (air or water) density - ANS-distribution of mass via out a volume of space; factors of fluid force viscocity - ANS-fluid's resistance to flow; factors of fluid force; thickness cross-sectional area - ANS-> increases fluid resistance nature of surface - ANS-smooth vs. rough