Question

Imagine you are holding an empty bucket with a weight that is about 10% as great as the heaviest object you could possibly hold. As you are holding it, your friend fills it with water, increasing the bucket's weight to about of the max weight you could possibly hold. Consider the changes in muscle activation from before bucket- flling to after. Check ALL OF THE FOLLOWING changes that will occur during this period: the number of active motor units will increase the motor units that are active at 10% max force will have a higher firing frequency at 90% max force Slow-oxidative motor units will be active at 10% force, but they will stop firing at 90% max-force in favor of fast-glycolytic motor units ?the excitatory input to the motor unit pool will be greater at 90% max-force than at 10% max-force At 90% max-force, there will be a greater % of active fibers within each motor unit compared to 10% max. force At 10% max-forc e, there will likely be no active motor units characterized as "fast", but at 90% max-force there will be For the motor units that are active at 10% max-force, the cytosolic Ca2+ concentration during the the motor units that are active at 10% max-force will experience much larger end-plate potentials during 90% contraction will exceed the cytosolic Ca2+ concentration during the 10% max-force contraction the 90% max-force contraction

Answer 1

*The number of motor unit activation is depends upon the amount of load exerted on the muscle , heavier laod will excite more number of moto unit as compared to the lighter weight , so that the muscle contraction will occur to combat load.

*The higher firing frequency at 90% max force is due to the more number of motor unit activation as compared in 10%max force.

*The fast glycolytic motor units are able to activate fast as compared to slow fibers but they have the tendency to fatique faster.

*The excitation input will be greater at 90% max force so that the maximum number of fibers get activate and causes strong muscular contraction.