posted July 03, 2000 08:54 PM            

Enjoy

Late

Lobo

AEROBICS AND BODYBUILDING:
Is There Room for Both?

by Lyle McDonald, B.Sc. CSCS

The common recommendation for the strength/power athlete (like bodybuilders, shotputters, powerlifters, etc.) has been that aerobic training of any sort will hamper performance abilities and should be minimized or eliminated completely to allow for optimal performance. The primary exception to this being bodybuilders who generally perform aerobic training prior to a competition to lower bodyfat and achieved a 'ripped' appearance. However, remember that bodybuilders are not judged on their strength performance but rather their appearance.

Some strength and conditioning experts suggest that no aerobic training be done by the natural strength athlete (8) citing several studies have found interference effects between concurrent high intensity strength training and aerobic training (3,4). The studies generally use a protocol similar to the following:

Strength group (S): trains 3 or more days per week with high intensity strength training of varying nature.

Endurance group (E): trains 4 or more days per week with two days allocated to distance training (at 75% of VO2 max. or so) and two days to interval or fartlek training.

Combined group (C): the combined group generally performs both training protocols but generally end up training more total days. In one study, the C group was doing 11 total training sessions per week (5 strength and 6 endurance).

All 3 training programs are increased progressively to maintain overload conditions. And, generally, up to about 8 weeks, the S group and the C group gain equal amounts of leg strength. However, in this and several other studies, at weeks 9 and 10, the S group
continues to increase strength levels while the C group begins to plateau and lose strength. Generally, upper body strength is not affected as the endurance training is using the muscles of the lower body as in cycling and running. This suggests that the problem may be localized (in that the legs are trained by both the strength training and the endurance training) rather than systemic (i.e. aerobic training decreases strength levels in all lifts) as well as suggesting that the problem is one of overtraining the legs rather than some other cause. The question, still remains as to why this phenomena occurs.

The SAID principle: SAID stands for Specific Adaptation to Imposed Demands and reflects the physiological basis of training specificity. That is, aerobic training leads to improvement in long term energy production capabilities (by increases in aerobic enzymes and mitochondria density and size) while high load, low repetition resistance training leads to an increase in fiber cross sectional area (primarily in the Type II fibers but also in the Type I) and in levels of glycolytic enzymes.

So, we seem to have an easy answer to why strength training and endurance training conflict with each other: The muscle fibers are being sent two distinct and contradictory messages from the two types of training, one of which says 'get smaller and more efficient aerobically' and the other that says 'get larger and more efficient anaerobically'. However, strangely, none of these studies has yet to find a decrease in aerobic performance with high intensity strength training as might be expected if a strict interference mechanism was responsible. That is, both the E and C groups improve their aerobic level (measured by VO2 max) equally.

A recent study (9) found no interference effects. They used the same three groups as above (strength only, endurance only, and combined) but the difference was that the C group trained only 3 times per week doing both their strength training (8 exercises for 4 sets of 5-7 reps) and endurance training (50 minutes at 70% of heart rate reserve) at the same time. The sessions were alternated so that one day they did endurance work before strength work and the other they did strength before endurance with no less than 10 and no more than 20 minutes between workouts. Interestingly, no interference effects were seen over the 10 week length of the study. So, rather than strict interference effects, the previous studies' (which, recall had the individuals training their legs 5-6 total days per week) results may simply have been overtraining of the legs. When legs were worked only 3 total times per week in this study, no decreases in strength were seen.

The ACSM guidelines: The American College of Sports Medicine (1) recommends that an individual exercise between 60-85% of their age adjusted maximum heart rate (estimated by 220-age) for 20-60 minutes to improve their cardiovascular fitness and health. While this type of general recommendation may be suitable for the average individual, it's not specific enough for athletes looking to optimize either strength or endurance abilities who need a bit more specific recommendation. By comparison, the ACSM position stand also recommends one set of 8-12 repetitions taken to fatigue of the major muscles in the body done twice per week to improve muscular fitness but I think we would all agree that this isn't going to be enough for an elite strength athlete.

That is, 60-85% is a pretty big range for cardiovascular training. For a 24 year old individual with a maximum heart rate of 196, 60% of max is 117 beats per minute which is a fairly slow walk while 85% is 166 which is a brisk run on the treadmill. Obviously the latter will take far more out of your recovery ability than the former.

Most of the interference studies are combining high intensity strength training with high intensity endurance training (in an effort to approximate what a competitive athlete such as a football or rugby player, who must have both abilities developed, might do in training). But, does this type of training apply to the elite strength or endurance athlete (i.e. those who must improve one in lieu or at expense of the other such as a marathon runner or powerlifter)? The answer is no. Few if any elite strength/power athletes need to be working at anywhere near this intensity in their endurance training. It's not specific to their sport in the way that high intensity endurance training is specific to something like rugby. And, few endurance athletes (although they really should) work at a high intensity in the weight room. Interestingly, while high intensity endurance training may cause problems with strength training, the opposite does not occur.

Other studies that subject endurance athletes to heavy resistance training find not only no decrease in VO2 max but rather an improvement in aerobic efficiency and time to exhaustion at lactate threshold (5,6).

There are three primary types of muscle fibers in your average skeletal muscle: Type I - which generate little force but fatigue slowly and are used during low intensity, long duration activities; Type IIa - intermediate fibers with both oxidative and glycolytic capabilities; and Type IIb - fast twitch, highly glycolytic fibers which generate the most force and also have the capability for the most growth.

The size principle and fiber recruitment: Muscle fibers are recruited during strength training according to the size principle from smallest (the Type I) to largest (Type IIb) depending on the load lifted as well as other factors.

The muscle fibers are recruited in exactly the same way during endurance training. Very low intensity endurance training generally recruits only Type I fibers. As intensity increases (and something called the lactate threshold is approached) the Type IIa fibers are called into play. Once you go past the lactate threshold and approach maximal 'aerobic' intensity activities like high speed intervals, the Type IIb fibers are recruited and the signal sent is for these fibers to become more aerobically efficient and that's where the problem comes in with combining both high intensity endurance and strength training. Type I fibers don't generally grow all that much in response to strength training and they surely aren't that important for maximal strength output. However, they excel at low intensity endurance activities. The Type IIa fibers can go either way. If they are trained aerobically, they become more aerobic. Train them anaerobically and they grow and become more anaerobic. Type IIb fibers are your major strength fibers. It's when you start sending mixed signals to the Type II fibers (by recruiting them both with high intensity endurance activity above the lactate threshold as well as high intensity strength training) that you get problems. So, what's the solution?

The lactate threshold: Although it's poorly defined and vigorously debated, the lactate threshold (LT) essentially is the point above which lactate generation is greater than lactate clearance. This results in increasingly higher levels of lactate which causes the familiar burning sensation and inhibits muscular contraction. Although it varies from person to person, the LT may occur anywhere from 50% of VO2 max. (in untrained individuals) to as high as 85-90% of VO2 max. (in highly training endurance athletes).
Recall that it's around the LT that Type IIa fibers become involved. Between the LT and maximum, Type IIb fibers get recruited. So, we have a possible answer to the problem of interference: stay well below the lactate threshold (2). So, how does one know where their LT occurs? Unfortunately, it's not easily tested outside of the lab. Some have suggested (2) using the talk test or, more technically, the onset of unstable ventilation (where it becomes difficult to maintain a continuous conversation) as a general indicator of the LT. Unfortunately, this is not accurate in all people (10) and should not be used. Another subjective way to determine LT is to gradually increase exercise intensity until the point that you begin to feel a burning sensation in the muscles being used. This is essentially your LT. Please note that you should take 3 minutes between raising workload both to allow heart rate to stabilize as well as lactic acid levels to stabilize. Take your heart rate at this point and work out a minimum of 10 beats per minute below this level to make sure you're below LT. Alternately, simply stay nearer the 60% of maximum heart rate suggested by the ACSM which should keep most people well below LT.

So, for the natural strength/power athlete, except for pre-contest, is there any real reason to include regular cardiovascular exercise? Let's examine some of the potential impacts of regular low-intensity cardiovascular training on strength performance. Health: Sometimes in the quest for optimal performance, athletes forget that one of the main purposes of training is improved health. Cardiovascular health is an important facet of overall health and can be developed with a mere 20 minutes of aerobic exercise 3 times per week at the proper heart rate.

Performance and recovery: While it's inadequately studied, some have suggested that aerobic conditioning might hasten recovery both on an acute and long term level. Both high intensity strength and endurance training (weight training, intervals, etc.) utilize primarily anaerobic energy pathways (the ATP-CP and lactic acid systems) due to their short duration. However, recovery between anaerobic bouts is mediated almost exclusively by the aerobic energy system. So, it's possible that having a somewhat improved aerobic system might allow for faster recovery between acute bouts of activity. This might allow a greater training volume which might then lead to greater adaptations down the road. Long term recovery is mediated by things such as hormonal levels, nutrient influx to the muscle and the removal of waste products. Improving your aerobic capacity may improve the ability for hormones and nutrients to get to the muscle by increasing capillary density and overall blood flow as well as helping in the removal of waste products such as lactic acid.

Other hormonal considerations: A recent study by Kraemer et. al. (7) found an increase in cortisol as well as a decrease in anabolic hormones with concurrent training which might also limit strength and muscle size gains. They too combined high intensity strength training with high intensity endurance training including intervals, although total training occurred a maximum of only 4 days in the C group. Realize that any high intensity activity done too frequently will lead to a gradual increase in cortisol as well as decreases in anabolic hormones like testosterone. This may have been one of the causes of overtraining in the studies that had the individual training a total of 5-6 days per week in the combined training groups. Recall that the study that only used three total training days per week (which would allow for more days of total recovery) found no such signs of interference.

So, in conclusion, some mild aerobic activity may have the potential to improve anaerobic performance by improving recovery between sets and between training sessions. This may allow more work to be performed during training which may lead to greater strength improvements. I'm not saying here that all strength and power athletes should try to become the next Alberto Salazar and win the New York Marathon. But, a little light endurance training is probably not going to hinder performance and might actually improve it somewhat. Some guidelines for proper endurance training for strength and
power athletes:

1. Stay well below lactate threshold. See above for various methods to determine LT.

2. Keep duration of endurance training to the minimum. There is a gradual increase in usage of protein as a fuel for endurance training as duration increases. 20-30 minutes of low intensity cardio done 2-3 times per week should be more than plenty.

3. If at all possible, try to do cardiovascular training on the same days as you do your strength training. This allows for more total days of recovery. A 20 minute brisk walk or bike ride before training will make an excellent warm-up. A 20 minute walk after training may help with recovery (do make sure to start sipping some carbs during this period to help with glycogen replenishment). Try to make your days off complete days off.

4. When you are nearing periods of maximal training and recovery is at it's limits, cut back or drop cardio completely. Cardiovascular endurance can be maintained with training twice a week as long as duration and intensity are maintained.

5. Additionally, you might also try incorporating a 'fitness cycle' during periods of light weight training. Since your recovery abilities aren't being taxed to the max, put a bit more emphasis on
your aerobic training and then simply maintain what you've developed (with two 20 minute sessions per week) during periods of heavier training.

6. Try to pick non-impact training modes like walking on a treadmill, cycling, or stairstepping. The extra mass carried by most strength athletes can lead to joint problems down with the road with high impact activities like running. Also, aerobics classes aren't generally recommended as there's no way to ensure you are staying below your LT (2). The same applies to the random or hill program on most bikes and steppers. Also, for some reason, running seems to strip off muscle more so than any other aerobic activity and is not recommended.

References:

posted July 04, 2000 11:23 AM            

Other hormonal considerations: A recent study by Kraemer et. al. (7) found an increase in cortisol as well as a decrease in anabolic hormones with concurrent training which might also limit strength and muscle size gains. They too combined high intensity strength training with high intensity endurance training including intervals, although total training occurred a maximum of only 4 days in the C group. Realize that any high intensity activity done too frequently will lead to a gradual increase in cortisol as well as decreases in anabolic hormones like testosterone. This may have been one of the causes of overtraining in the studies that had the individual training a total of 5-6 days per week in the combined training groups. Recall that the study that only used three total training days per week (which would allow for more days of total recovery) found no such signs of interference.

Simply put: excessive, unrelenting stress from any source be it from exercise or psycological can ultimately result in hypothalamic repression. Anyone ever notice how both he and she competitive-level endurance athletes tend to resemble each other as they minimize their respective hormonal production?

posted July 05, 2000 02:40 PM            

Has anyone else read much lately about how cortisol levels may be linked to abdominal fat storage? Interesting...

Gives yet another reason to NOT STRESS OUT!