Fat % down, waistline up? huh?

neilkod

I've been actively biking and spinning for about 6 months now and have lost quite a bit of body fat (from 33% down to 16%) and weight.

However, my legs seem 'bigger' and my pants are tougher to put on these days! Is this normal?

Aztec

You SURE about this?

Possible explanations are bloating (has your diet changed?). Maybe the BF% measurements were hugely inaccurate. Have you lost all that much weight? The only other possible explanations are that your midsection muscles have thicked (highly unlikely unless you've been doing weighted ab work and hyperextensions, etc) or that your fat loss was nil over your waist (not likely if you are male).

neilkod

I should say that its tougher to get my pants up around my legs. Is an increase in leg size to be expected?

Aztec

OH! Depends on the person and the level of previous fitness. If you hadn't been doing much, then just about anything would beef up the legs at least some.

zaskar

wow it sounds like the% may not be right, how does
your wieght compare to fat%. for me cycling 10-15 hrs
a week for 3 months i lost 7 lbs from 21% body fat
to 18%

mfallon

This is not only normal but to be expected. Your building muscle as well as burning body fat. You may also notice at some point your weight will start climbing very slowly as you continue to build muscle even though your burning fat since muscle out-weights fat. This is a good thing. It means your getting more fit. If you feel like your legs are getting too big you can always try spinning at a higher cadence especially up hills so that your increasing the aerobic work and decreasing the anaerobic work since anaerobic builds more muscle.

Matt

neilkod

I just started training with a HRM. For 1hr, I average 161-166 (resting is 65, max so far is 196). At what point does the switch between aerobic and anaerobic occur?

less'go

I have had a similar experience, after expecting to see measurements decrease with steady excercise...

In my case, my weight has slightly increased (but is now much more stable), as have my body measurements in certain places since I began cycling and doing other excercise.

I decided at some point not to worry about it too much, because I can tell just by looking that I am in much better shape. But still, it got me thinking:

Maybe it's possible to build muscle more quickly than you burn fat, so that at some point you have both. This would naturally explain the added cm as being the combo of muscle + residual fat.

Hopefully, as you keep going, the remaining fat will diminish and the muscle will keep developing.

In any case, thet entirely made-up and unscientific explanation keeps me happy for now!

Besides, sounds like you're getting a Hulk effect going there... You could be onto something.

Sara



(my goal is more to get in good shape than lose actual kilos)

__________________
The six-pack will be mine...

neilkod

Yeah, that's the same boat I'm in. What's funny is that I haven't really lost any lbs of body weight, but quite a bit of fat (noticeable). I'm not chasing a weight, but rather a 'feeling' and a %of body fat.

I shouldn't have said waistline up, but now I need bigger pants to accommodate the increase in leg size!

mfallon

It's really not a "switch" but rather an increase or decrease in one over the other. Most exercises including cycling actually use a combination of aerobic and anaerobic energy. By using a smaller gear and not trying to power up the hills you increase the use of aerobic energy while decreasing the use of anaerobic energy. Staying within the typical 65%-85% of max heart rate should keep you in a range that uses mostly aerobic energy. If you want more detail read on otherwise ignore my further ramblings (you won't hurt my feelings).

I only have a very basic understanding of these processes but here goes. The muscles are made up of two major types of muscle fiber; fast-twitch and slow-twitch. Fast-twitch muscle fiber uses anaerobic energy while slow-twitch muscle fiber uses aerobic energy. Everyone has some combination of fast-twitch and slow-twitch muscle fiber and each person is different. If you have mostly slow-twitch muscle fiber then you have the potential of being a world-class endurance athlete. If you have mostly fast-twitch muscle fiber then you have the potential of being a world-class weight-lifter or bodybuilder. Most people are somewhere in between.

Aerobic means "with oxygen" and relies on oxygen for energy. Anaerobic is the opposite "without oxygen" and relies on glycogen stored in the muscles for energy. Aerobic energy is used during moderate exercise and produces smaller amounts of energy over an extended period. An examples of aerobic exercise would be walking or jogging. Anaerobic energy is used for quick bursts of a large amount of energy or when the amount of energy needed exceeds the intake of oxygen. The dreaded lactic acid is a by-product of anaerobic energy. An example of anaerobic exercise would be weight-lifting or sprinting. One of the effects of stimulating fast-twitch muscle fibers is an increase in size. This is why weight-lifting since it is anaerobic, results in an increase in muslce size. You'll also notice that sprinters tend to also have fairly large legs since they are doing more anaerobic exercise and stimulating the fast-twitch fibers more while marathon runners have smaller legs since they are doing more aerobic exercise and thus stimulating the slow-twitch fibers more.

So as you can see everyone is different and the make up of your muscles combined with the type of exercise you do will determine how much of an increase you will have in muscle size. I hope this helps explain things rather than confusing the issue more

Matt

less'go

Matt's explanation of the diferent types of muscle dbuilding is very interesting. I had once read that the bigger the gear, the fatter your knees, or something to that effect... meaning that doing long, hard movements (more anaerobic) builds up bulkier muscles than doing fast (aerobic) movements.

I myself tend to go for bigger gears and use weights and other things for resistance training, so maybe by using less weight but doing more reps, or using a smaller gear and pedaling faster, I can get more long and lean muscles and less bulk...

I'm not sure, but it seems to be making sense!

Sara

__________________
The six-pack will be mine...

mfallon

That's pretty much it. You don't want to go so fast that your practically sprinting though since that would put you back in anaerobic training (although I would imagine from a cycling standpoint doing a little of that would be beneficial). For resistance training anything below about 8 reps is considered optimum for strength. Between 8-12 reps would be optimum for building size while over 12 reps would be for shaping and toning. But different reps and weight within these ranges work best for different people (think of them as just guidelines). The reason for the long winded explanation is so that you understand that this is very general. I knew one girl that would build bulk in her legs if she did any resistance training at all no matter how light and how many reps she did. At the same time I've seen guys that had a terrible time building any muscle even with heavy weight.

If you haven't guessed yet most of my experience is with resistance training. I'm new to cycling but much of the same principles apply since muscles are muscles. Cycling at first was just an experiment for me. After wrecking my knees in my younger days doing squats I decided to see if cycling could provide a decent leg workout while giving me a cardio workout at the same time. It doesn't bother my knees because I only have a problem when I put too much stress on them when they are bent too deep. With my seat adjusted properly this doesn't happen. What I didn't expect was that I would love cycling so much. So I currently ride 3-4 times a week and do resistance training just for my upper body. I know the extra weight from building muscle in my upper body will slow me down a little especially up hills but I like to keep my body balanced. I just make sure I don't use as heavy of weight as I used to. It's much better for the joints that way anyway.

Matt

Matt

2LAP

Sometimes its nice to be normal!

This 'creep' in weight due to gains in muscle are unlikely to happen through endurance cycling activities like spinning. After an initial gain in muscle size this should stop and in the long term (particularly if you keep doing the same) your muscle size may even go down again! The rate at which muscle is 'built' is much slower than the rate at which fat is lost, so you could get an increase in muscle and decrease in body weight. All women 'struggle' to gain muscle mass from training relative to men (due to testosterone) and endurance cycling activities (i.e. not sprint cycling) are unlikely to make you have large muscles/be muscle bound (I can't think of one 'over' muscular male or female endurance cyclist).

The contribution of aerobic and anerobic energy is primeraly determined by power output not cadence; therefore spinning very quickly or slowly at low intensities will have a low anaerobic contribution. Also the relationship between anaerobic energy contribution and 'muscle building' is complex, anerobic metabolism during endurance exercise is very unlikely to 'build' significant amounts of muscle. Rather building muscles or 'hypertrophy' is the reserve of specific types of training.

2LAP

While anerobic and aerobic metabolism are 'switched' on all the time, the rate of both energy systems increases with intensity. At the lactate threshold the body accumulates lactate (the by product of anaerobic metabolism) as it is unable to 'process' it at the rate the lactate is produced. Increasing pedaling rate may also increase the anaerobic contribution to the exercise if power output is maintained due to the increased energy cost of pedaling faster.

Both types of muscle fibres can use aerobic or anaerobic energy, yet as you suggest the fast twitch tend tpwards anaerobic metabolism and slow twitch tend towards aerobic metabolism. With training your fast twitch can become very aerobic as mitochondrial density, aerobic enzymes and capilarisation of these fibres increases. Endurance athletes TEND to have more slow twitch fibres and the opporsite is true for sprinters; however this does not infer potential. People with low numbers of fast twitch fibers can be good sprinters, by increaseing the 'cross sectional area or the volume of the fibres' and by doing this they can have 'more effective' fast twitch fibres than someone that has a high number of fast twitch fibres but which occupy a smaller volume or cross sectional area. In humans there is no good evidence to suggest that fast and slow fibres can change their type or that the number of fibres change (rather bigger muscles are due to bigger fibres).

Spot on, another example of anerobic metabolism is attacking in a road race or riding above your time trial pace.

Weight lifters and sprinters have large muscles due to specific weights exercises in a gym/weights room. Sprinting on a bike (either on its own or as a part of an endurance ride) will not result in muscle growth to any great extent. It is not the 'anaerobic metabolism' that stimulates bigger muscles directly.

Great post Matt, have you checked out the other threads on aerobic and anaerobic metabolism, fibre types and hypertrophy. I think you could make a good contribution to them.