You go to the gym with a friend and they tell you they want…

You go to the gym with a friend and they tell you they want to work their core. Because you are so smart, you know there are 4 primary muscles that make up our core musculature. When your friend is doing normal crunches, they are primarily working the 6-pack muscle known as the (transverse abdominis, rectus abdominis, rectus femoris, biceps femoris) . When they are doing bicycle crunches in which they are crossing their RIGHT elbow to the LEFT knee, they are working the right (internal or external) oblique and the left oblique.  

A friend injures their ankle so you ask how they got hurt. T…

A friend injures their ankle so you ask how they got hurt. They tell you they stepped off a curb and rolled it. As you think about the mechanisms for how this injury would occur, you piece together your knowledge of corpuscles, proprioceptors and actions of muscles to understand what happened. As the student stepped off the curb, their ankle rolled into plantarflexion and inversion. The corpuscle that would have sensed this dangerous change in joint position is the corpuscle. At the same time, another proprioceptor that is sensitive to stretch and rate of stretch, the , would have been stimulated in the muscles in the lower leg that are responsible for plantarflexion and eversion. These muscles are the . The nervous system would simultaneously send information from the receptors around the ankle to the CNS via an neuron. The CNS would then send information back to the receptors via an neuron to stimulate a corrective movement.