I just started using an elliptical machine at the gym to try and build some endurance when swimming/diving.
1. Would it be better to stay on the machine longer and lower the intensity or increase the intensity and stay on it for less time?
Thanks.
Both should be included as part of your routine but consider a few factors:
- Diving itself is NOT a physical activity. In fact, the better divers are all about energy efficiency to make their gas supply last longer.
- The activities that lead to diving could be physically demanding depending on your current physical conditioning and the relation of you and your gear. 60 lbs of gear is barely noticeable to a 200 lb diver. It is not the same for a diver who barely weighs 110. Your strength plays a crucial role in dealing with these factors successfully.
- The activities that could arise as a result of a diving emergency could also be very physical. Again, a crucial factor is your strength.
The reason I bring up the above factors is to remind you that all your physical performing capacities are an expression of your strength.
To be specific to your question, going intense for short bursts can be very productive in developing physical endurance, but to get the most of this level of training, you have to have a good level of strength.
The long low intensity can be a good starting point, or a welcome break from the intense bouts, but monitor the length of your activity. Joints are not too fond of overuse in the same pattern.
Finally, stay away from anything that tries to mimic the demands of diving. Diving is more of a set of acquired skills than physical prowess, and the only thing that can get you better at diving is well, diving.
That is not to say you should not engage in physical training as your physical fitness will be challenged when you least expect it. The point is that any form of physical activity as long as it's well rounded, methodical, and delivers results without destroying your body will make you fit to handle the demands of diving. Do not select exercises or methods just because they mimic diving motions or positions. It is not a productive approach.
Have fun!