Aerobics vs Weight Training

[Jorpho]

I've seen quite a few blurbs about this, but I've never been especially clear on the details: it is said that aerobic exercise and weight lifting are incompatible.

But how exactly is this so? If I, say, run for half an hour on a treadmill and then lift some weights, would I benefit more or less than I would if I did it the other way around? Or what if I ran for an hour on a treadmill and lifted weights on alternate days? Wouldn't warming up on a treadmill (or exercise bike or elliptical or whatever) for fifteen minutes (?) still be beneficial prior to weightlifting anyway?

[Nath]

I don't think they are incompatible. It's just that people tend to do them for opposing reasons. People often do sustained, moderate-intensity aerobic exercise to lose weight. People often lift weights to build muscle. It's hard to succeed at both of these things simultaneously.

In principle, there doesn't have to be a contradiction. You probably want a balance of aerobic and anaerobic exercise that suits your objectives, and a diet to match. If you mainly want to build muscle, you need to eat well and avoid burning all your calories jogging. If you want to lose weight, you'll probably lose a bit of muscle along with all the fat. So it goes.

Disclaimer: not an expert.

[Victoria Maddison]

Adequate intensity is necessary to become stronger, however if your muscles are fatigued from running they wont be able to generate anywhere near this amount of force, and so your progress would be impeded. Furthermore, distance running is catabolic. Running will only hinder your performance in weight lifting. On the other hand, running will benefit from the increased strength and muscular efficiency that weight lifting provides. So whether or not they're incompatible depends on your goals.

If you're going to do both then you should lift weights before running for the above reasons. Alternating between days of running and lifting will be taxing, and a beginner may have trouble recovering from it (although people can and do). A better solution is to lift in the mornings and run in the evenings with the following day as a rest day, e.g. working out Monday, Wednesday, Friday in both mornings and evenings. This would significantly aid recovery.

A 5 minute aerobic warm up before lifting is more than enough. You'll still need to do your warm up sets to get to your working weight if you lift heavy and want to avoid injury, so there isn't really anything to be gained by going overboard.

Edit: I've used running as an example here, however the points I've made above apply equally to other aerobic exercises.

[LordMantir]

I've heard from my work's Gym instuctor that lifting weights can be just as effective for losing weight as aerobics, because following a weightlifting session, the body's metabolic rate rises for up to 24 hours afterwards, whereas the fat burn in aerobics stops as soon as the session ends. He suggested a half-hour session of aerobics, concentrating on getting as far/fast as possible in that time (following a short warm-up) then doing a series of weight exercises. Just thought I'd thriow this into the discussion; it makes sense to me but obviously I'm not an expert. He said that doing aerobics for a long time makes the body concentrate on becoming more efficient, thus burning fewer calories and reducing fat loss.

[Oxymoronic]

They are compatible, but only to a point.
You can gain muscle and lose weight at the same time, but at a generally slower rate than if you chose one as your main goal.

[Jackpot]

While I am not an expert, my workout comes from an expert. I have a warmup, followed by weight training on machines, then aerobic exercise.

I told my instructor my goal was to loose weight and gain muscle mass.

[psyck0]

They are incompatible in the sense that you can only focus on one. You can improve your aerobic fitness slowly while weight-lifting, i.e. by going for short (20-30 min) runs after each weight session or on rest days, but if you make the runs too long your muscles won't recover from the weights and you won't gain any strength. Likewise, you can improve your strength slightly while focusing on aerobic fitness, by doing (I suggest) high-rep-low-weights, but if you do too much weight, your muscles will be too tired to let you push yourself aerobically. That's why most people generally bulk, then cut (gain weight and fat with a weight-only regimen and protein-calorie rich diet, and then burn the added fat off at a later point).

[bippy]

This is one of those questions that depends on the level of detail you want to attain. The first, most useless answer, is that it depends on your goal. However, if you are lifting, in almost all cases it is better to run after you lift. Running does tire out your muscles per se -- your triceps, shoulders, and pectorals do not do a lot of work running but benching after running will cause a drop in performance compared against a 'fresh' bench press -- it's more a question of metabolic conditioning and glycogen supply. The general principle (derived from Selye's theory of stress) is that your body adapts to the stress applied to it, and you can only apply so much stress at one time so you're best off lifting first.

With that said, if you are training as a runner you are best off training for your sport first. There are many reasons you might want to lift afterwards, but it would be a specialized kind of lifting -- for joint health, for instance. It would incorporate an exercise selection, intensity (weight), set and rep scheme, and rest interval all specifically geared towards that one goal. The more advanced you are, the more stress you need to apply to spur adaptation, the more zany your training protocol becomes.

One thing you DO want to do is properly warm up before lifting. Five to ten minutes of low intensity, low impact, steady state cardiovascular activity will increase the temperature of your tissue and increase the blood supply. This makes muscles better at all the things they do as well as increasing flexibility (and decreasing injury in turn). You also do warm-up sets before lifting with your working weight for that and some other reasons.

But again, it all depends on the level of detail. In general, if you plan to lift and run just for basic health you're best lifting first and running afterwards.