My primary goal at the gym is to build strength and muscle mass. But since I’m pretty out of shape, I can only do so much of that per week (and even less now with a shoulder injury), so I also do cardiovascular excercises - to get more excercise in general, to strengthen ligaments and tendons, and to increase cardiovascular endurance and efficiency. Biking, inclined fast walking (jogging is rough on my knees at this point), rowing machine, stairmaster, etc.
I’ve read that for the same amount of time, interval training will increase your cardiovascular efficiency gains more than constant-effort training, so I’ve been working on that. Typically, machines will have built in settings for interval training - but they generally affect the resistance rather than the speed of the machine. On bikes, the mechanism is partially braked to increase resistance, on treadmills the incline will change, etc.
Would the most efficient way to get better results out of my interval training be to increase and decrease my speed at a constant resistance, increase and decrease resistance at a constant speed, or increase and decrease both?
For muscle training, I highly recommend Shovelglove (www.shovelglove.com). I’ve only been doing it for 1-2 weeks and the results are noticeable. I’m sore in muscles I didn’t know I had!
It’s important to bear in mind that interval training is best done only after months of such constant-effort training so as to lay a “base” of fitness for later improvements. Yes, intervals mark a sharp increase–but one sees marked differences in the improvements gained by interval training depending upon how much base training that person had (comparing a person who missed two weeks due to sickness to someone who went through full-time, etc.). Interval training really makes the most of what fitness you have, and yes it does seem to have a more dramatic “getting back into shape” effect than slow training, but its long-term utility is limited…
The goal with interval training is just to temporarily increase your intensity. Whether you do it through resistance or speed makes no difference, really. The whole point is to raise your heart rate above your recovery level, which is roughly 60% of your max rate (calculator and discussion of max heart rate here). During your interval, depending on how healthy you are, you are supposed to work hard enough to spike up to 80–90% of your max. Checking your heart rate to keep you honest is good, but you can do it mostly by feel once you get used to what it’s like to go that hard.
Fartlek, which you might have heard of, is basically informal interval training. You pick a goal, like running from here to the tree at the end of the block as fast as you possibly can, and then return to pace. If you’re self-motivated or have a partner/trainer pushing you it works well and is more fun than computer-modulated training. You’ve got to be good about pushing yourself though.
That site also has a page on interval training and some other resources.
Bump. It doesn’t matter. Obviously doing both is more productive. First, protect yourself from heart-attacks by achieving a base fitness level. You’ll know you’re there because you’ve plateau’d. You won’t be sore, you’re heart returns to normal quickly, and weight loss and strength gain are minimal. Then work on your expolsive power. Although it seems contradictory, it’s actually easier on the joints to sprint until you’re out of breath than it is to jog until you’re out of breath. Training for power builds your muscles way more than training for endurance. Take the case of sprinters vs marathoners. Both can run 4-minute miles, but sprinters look like linebackers.