It all comes down to the fitness level of your participants. One minute might be to long for a beginners class but not for an advanced level. As to the format of the exercises, there is really no best way to ago about it. You can manipulate the sequence and types of exercises anyway you like. If you have 15 people in your class you can create 15 stations and be able to have them complete 3 rounds within the 45 minutes time frame (if each exercise takes 1 minute to complete including the rest period). This question can be answered in many different ways, so you need have an idea of the goals you are trying accomplish and then decide how you want to go about it.
I hope this helps.
If you have people who are interested in helping and take-charge kind of people, have them be the “leader” of the exercise at their station. Make sure you take them aside and give them proper form review and tips, and also make sure you keep control of your class and use them for visuals & motivators for the others primarily. It can help with the flow, proper form and technique, alleviate any confusion and also help with equipment setup / usage. you can’t be everywhere at once or they’d have cloned you! Have fun!!!
I find that one minute at a station is great for beginners because it gives them a chance to feel comfortable with the exercise at a low weight especially if they don’t quite get it right away. 45 seconds is great for a circuit that has a higher intensity. Depending on how you structure your class, your stations can be rep-based or time based. Rep based can be fun for more intermediate participants because it allows the participants to push themselves a bit and try and catch the person ahead of them. BUT, you need to make sure that you have enough equipment to handle at least 4 people at a station at once. You would want to stay away from machines and stick with body weight and equipment you have multiples of. In terms of structure, I find alternating upper, lower, core, cardio works well but if you have a high intensity class, you don’t need cardio as their heart rates are up the entire time!
I find it best for most fitness levels when I do 45 seconds for each exercise and a 15 second recovery where they go to the next exercise. During that 15 second recovery I assist any participants that may need a modification or not sure what they are suppose to be doing. I typically have 10 circuits with various exercises consisting of upper body, lower body, cardio, and core. I place signs up at each station so the participants know what they are to do at each station which saves me from running around instructing each participant.
A second way that I have successfully ran a circuit too is all of the above, but have the participants partner up. Group 1 does the strength exercise at the station while Group 2 does the cardio portion then they switch before moving on to the next station. This works really well for bigger classes or if more people show up than you expect.
I usually do a minute at each station. I find its easier for me to keep track and the participants as well. To make it flow easier, I show the exercise, a modification and a progression for each exercise. Then those who want more of a challenge can do so. Those who are just starting out, don’t feel singled out. I also let them know to try to get through the entire minute. If they need to drop to a modification, that’s ok, the goal is to just keep moving using good form and executing the exercise properly. If at any time form is compromised, they are to stop and march it out.