Find a volunteer to record a video of the knee reflex. Record (video) the response to the stretch reflex under three different conditions. The objective is to demonstrate the stretch reflex by tapping the patellar tendon with a rubber mallet (or any other soft element that can replace the rubber mallet). Conditions:
The subject should sit on a bench/table with legs hanging freely. Tap the patellar ligament. This assesses the L2-L4 level of the spinal cord. Test both sides. This will represent the baseline response.
Have the subject add several numbers together as you test again. This tests the effect of mental distraction. Is the response greater than or less than the baseline?
Test again while the subject pulls up on the bench/table with the arms while relaxing the lower limbs contract (the goal is to only contract the upper body without influencing the lower body) . This tests the effect of other simultaneous muscular activity. Is the response greater than or less than baseline?
Upload the video into the blog (all three conditions as one video) and provide a 250-word analysis of the three conditions. Discuss differences between conditions and possible reasons. I.e. Which is more likely responsible for the changes you observed – nervous system activity or muscular system activity?