Can you please tell me why elliptical trainers have a high perceived exertion rate, yet the heart rate does not always match? Why are they so challenging, even for a fit individual?
I am unaware of any research completed with an elliptical type machine. The reason for this is unclear due to the popularity of this piece of equipment. However, we can explore your question and try to extrapolate a reasonable answer as to the function of an elliptical trainer (ET).
As you have stated, most people find this machine difficult. It seems that the motion by itself is difficult to do and is an unnatural movement. Let's briefly mention a few things while looking at the way the body works when using the ET. The first thing is the foot never leaves the footboard. That constant contact time may increase the time of work and therefore increase the Rate of Perceived Exertion (RPE). Other events that cause constant foot contact like the ET is cross country skiing or the ski trainer. As you know, cross country skiing requires a lot of work and therefore very high RPE. Next glance at the ET shows us there is no “glide” phase. This means you are working constantly and never get to coast, which causes high heart rates and RPEs. The last obvious thing is cooling. Here you are, working like crazy, and you get no airflow unless you have a giant fan blowing on you. If you are outside running, riding and even snow skiing, you get airflow and evaporation for cooling. Most places I have seen have minimal airflow in the aerobics area, which causes people to sweat like mad and feel like they are working to the max. And they probably are due to the amount of body heat they are generating and their high RPE.
Here is another question: can someone using an ET improve his/her fitness level for another work environment? With no real research to answer this question, it becomes speculation. However, here is what I have observed while working with a group of firefighter clients. Six out of 75 students trained on an ET device before a Physical Agility Test (PAT). A PAT is made up of running with and without hose, crawling with hose and a lot of stair cases, with and without hose. This test is the first big step in getting hired, and it is looked at with great importance. After taking the PAT for time, they did not do very well and ALL six of the students dropped the ET and started running and doing stairs as suggested. What makes their decision compelling is they all decided to drop the ET independently, without talking to each other. I found this very interesting.
I do not know if this helps you and your client, but you may want to ask the client(s) why they like the machines and go from there.