Just what the title says. What will be the tradeoff of losing weight only by running on a treadmill instead of doing separate muscle group workout?


8 Answers 8


Losing weight is more about burning calories than using different muscles.

Running has several advantages:

  • it's weight bearing, so you are your own workout tool. The harder you run, the more energy it will require: enter image description here
  • running uses more than just the legs, because you have to stabilize your torso against the swings of your legs. This trains your abdomen and uses the arms.
  • everybody knows how to run, because it's just a faster way of walking. Not everyone knows how to properly lift weights or perform other workouts (without training).
  • running is easy to maintain for long stretches of time when done at a moderate speed, yet burns a lot of calories in the process. This is excellent for burning fat.
  • running has a very constant rate of burning calories, whereas most other exercises like lifting weights often consist of bursts of high intensity workouts. The high intensity means you're burning more glycogen rather than fat, compared to during a moderate running workout, even though you can feel exhausted after both.

So no, you don't have to do anything else but running, however if you want to loose more weight: run more! Be careful for working out too often, too hard or too long, it might get you injured. Instead, focus on building up a better fitness and in a couple of months you'll be able to run longer and more often, that's when you really start to loose weight. So just be patient!

  • Using that equation doesn't really work. The kinetic energy of a moving object is equivalent to the energy needed to accelerate that object from rest up to that speed. After that, it's at best very indirectly related to the work (energy expenditure over time) that you're doing. See Wikipedia for the basics: en.wikipedia.org/wiki/Kinetic_energy Mar 15, 2011 at 1:58
  • @Matthew, you're body isn't a car that stays at that speed magically. You have to propel your legs every step, those legs have a weight and their speed is most certainly not constant. Furthermore, your forward speed may be 'constant' but bouncing up and down like you do in running requires forces that need to be generated. The more you weight, the higher the forces and the harder you'll have to work.
    – Ivo Flipse
    Mar 15, 2011 at 10:55
  • 1
    @Ivo I completely agree. My point is that that particular equation can't be used to determine the amount of work you're doing. Mar 15, 2011 at 12:35
  • Ah @Matthew, it was meant to emphasize the thing that using your own (heavy) weight is a great tool and that moving it 'faster' costs more energy. But off course, this is a great simplification
    – Ivo Flipse
    Mar 15, 2011 at 12:39
  • OK @Ivo. Sorry I keep "picking" on you, your answers are generally some of the best on the StackExchange network! :P Mar 15, 2011 at 12:45

If it is only losing weight you're after, then Yes, as Ivo Flipse stated, running will do you loads of good.

On the other hand, I don't approve of only losing weight, as in loosing only fat. That is probably going to leave you in a great athletic shape, but with not much upper body strength. Therefore I would encourage you to do at least some upper body training, eg.

In short,

Yes, you will, but probably not much muscle gain in that.

  • Not everybody wants to look like a body builder ;-) Besides you can loose weight and still not be slender or athletic. I think it's better to loose some weight first and get into better shape, before doing additional workouts. But in the end it's all down to preferences
    – Ivo Flipse
    Mar 14, 2011 at 21:02

Regarding energy use in exercise:

1 kilocalorie = 3,085.96 foot pounds (Don't believe me? Type "1 Calorie in foot pounds" into google)

A kilocalorie is the same thing as a food Calorie. A foot pound is the amount of work it takes to raise a weight of one pound by one foot against standard gravity.

Your basic 100 Calorie snack pack thus contains enough energy for you to lift a 154 ton object a distance of one foot, or for a 150 pound person to climb a 2057 foot cliff (assuming perfect muscle efficiency).

Changing your diet by restricting Calories is far more effective for weight loss than running, or pumping iron. When I do 3 sets of 10 leg presses at 450 Lbs, I'm lifting the equivalent of 27,000 pound through a distance of 1 foot (450 X 2ft X 30 = 27,000), But that takes only 9 Calories to do. That's just slightly more than what I'd get eating half a teaspoon of sugar (15 Cal/tsp).

  • Oh yes, there's the whole 'ramping up metabolism' achieved by getting regular exercise thing, but no matter the size of that effect, a Calorie still represents a HUGE quantity of work exercise-wise.
    – user461
    Mar 14, 2011 at 23:49

It's going to take less energy for a muscle to perform an action if it has been trained to perform that action where as an untrained muscle is going to require far more energy to do the same action.

Running is a great way to stay in shape and lose weight but inlcuding other cardio and focusing on all of your muscle groups will increase your results.

After a while you'll notice that you're going to have to run longer and longer (or find some way to do more work while running, maybe change the incline) to see the same results.

The results are not linear and will flatten off.

  • 1
    Eventually you'll get so effective at running that it isn't an effective cardio workout anymore. For me that happened pretty quickly, although I guess it'll vary by person. Aug 21, 2011 at 3:36

Depending on your pace, you'll most likely be doing an aerobic exercise, since endurance is essential for running. You'll be using a lot of muscle groups on your legs mainly to maintain forward moment and to some extent your back muscles for balancing, rotating the rib cage and to improve your air flow, depending on your running style.

That's already a large surface, so expect to burn fat effectively. You'll be toning the muscles that are heavily involved in the exercise, but you won't be gaining any considerable mass, which is sometimes hard to achieve if you get too carried away when focusing on a certain muscle group.


Since it has not been mentioned here:

Running is a good way to lose muscle mass. There are multiple studies suggesting long distance runners have lower testosterone levels and higher cortisol levels. Lowered testosterone is associated with loss in muscle mass while elevated cortisol is believed to hold on to fats.

Note that although these are generally accepted by most of the fitness community, it is possible to find contradicting studies, i.e., there is no consensus in scientific community.

I trained for marathon for two years. I run around 60 km a week. I started it with 13% fat ratio and finished it with 22% fat ratio. I stayed at the same weight (171 cm/63 kg). The reduced muscle mass caused to put on some weight after I quit marathon training. (71 kg in two more years.) Of course, this is my personal experience and has little meaning compared to scientific studies.

I suggest you to not overdo running if you want to get in shape and stay that way. 20-30 min running is a great way to enjoy a sunny afternoon and warm up for other exercises, but it shouldn't be your core exercise.


Depends on what your goal is. If you're just looking to lose weight, either running or some full body/body weight routine is fine. Part of the deciding factor is if there's other goals you're looking to achieve, if you have any health limitations, time limitations, etc. Take a look at fitdeck (www.fitdeck.com) for an example of some full body/body weight exercises that you can do in a limited space.


I always told that cardio helped you lose weight while running but building muscles helped you lose weight while you're not at the gym. I lost 50 pounds last year and what I did was have a days of cardio(spinning, kickboxing) and then 2 days of weight training. But to try to get the best of both worlds on my weight training days I would start with a run for 15-30 minutes and get my heart rate up, then do my weight training while my heart rate was elevated.

I have a heart reate monitor, so when it dropped below a certain level then I'd go back on the tredmill and get my heart rate back up. This way my weight training was also like a cardo session as well.

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