Rapidly and repeatedly moving the body from a standing upright position to a prone position on the floor, such as a movement like the burpee, is one of the quickest ways to increase the heart rate, and thus exercise intensity. In biomechanical terms, this depicts a large vertical displacement of the body’s center of mass (COM) (the balance point of an object's mass, around which if a pivot were placed, the object would remain in place and be balanced). In humans, the COM changes as body position changes, but for our purposes, imagine the COM located in the lower torso just above the pelvis. If you apply the physics principle of force, where force equals mass times acceleration (F = m x a), then it’s clear that any time you increase the velocity at which you move a mass (in our example the mass is the body’s COM) the resultant force will increase. In other words, to move your body rapidly requires the muscles to generate increased force at a high metabolic (caloric) cost. The farther and more rapidly you move your COM, the more force your muscles will exert to perform the activity. This results in a heart-pumping, high-intensity movement.
But aside from the physics, what you’re really asking has more to do with the safety of performing these types of large position-changing movements. The answer as to whether or not these moves are safe lies in the health status and conditioning level of the individual performing them. If any of the following factors applies to you, a medical evaluation is recommended before you perform any vigorous-intensity physical activity like what you have described in your question:
• The presence of known cardiovascular, pulmonary, and/or metabolic disease
• The presence of cardiovascular risk factors
• The presence of signs or symptoms suggestive of cardiovascular, pulmonary, and/or metabolic disease
To determine if you’re fit for vigorous activity, consider taking the Physical Activity Readiness Questionnaire (PAR-Q).
The second precaution to consider is your current level of conditioning. Performing vigorous activities like high knees, jumping jacks, squat jumps, burpees, and mountain climbers are excellent choices for most healthy people who want to increase exercise intensity and work in an almost anaerobic zone. If you have no health risks and are already somewhat physically active, you should have no problems transitioning from standing, to the floor, and back up to standing again. Just be ready to feel the intensity because those moves are sure to get your heart rate really high!