2009 Studies & Research Blog

By now there’s already a good chance you’ve read something stating the benefits of high intensity interval training (HIIT).  This is a form of cardio training where you perform a very intense interval at an almost max out pace for somewhere between 20-60 seconds, supplemented with a minute to two minutes of active rest.  This work-rest protocol is then repeated for a total of 6-12 times, making for a very intense 20-30 session of cardio.

Some of the primary benefits you’ll get from this form of cardio are decreased time spent in the gym (which we all could use), an increased metabolic rate after the session is over, a lower chance of muscle mass loss when the sprints are implemented correctly, and a greatly enhanced physical fitness level.

Now though, it appears there’s yet another benefit you’ll be getting from doing this form of exercise, namely, an increase in total fat oxidation rates.

Researchers out of the Department of Human Health and Nutritional Sciences in Guelph, Ontario recently looked at the impact on lipid oxidation rates after two weeks of interval training in moderately active women.

They had eight women perform ten 4-minute bouts of at approximately 90% of their VO2 max with two minutes of rest between interval training for two consecutive weeks and then measurement the impacts on plasma ephinephrine, heart rate, VO2 max, and fat oxidation rates.

After the two weeks were completed, the results indicated that VO2 max increased by 13%, both plasma ephinephrine and heart rate were lower during moderate paced exercise sessions after the interval training had taken place, and there was a 36% increase in body fat oxidation rates and after moderate paced exercise sessions, net muscle glycogen utilized was reduced.

So, from this study we can conclude the high intensity interval training will help increase the body’s ability to use fat as fuel after the interval training is completed as well as when you are performing more moderate intensity exercise.

This can prove to be very beneficial since muscle glycogen is often a limiting factor impacting the fatigue you feel on any given workout session, so the less reliance you have on it, potentially the better you will be able to workout.

Reference:
Bonen, A. et al. (2007). Two weeks of high intensity aerobic interval training increases the capacity for fat oxidation during exercise in women.  J. Appl. Physiology. University of Guelph, Guelph, Ontario. Aprl;102(4):1439-47.

Personally, I’ve never been to particular about the order in which I do exercises when I go to the gym, except when I’m planning on performing supersets.  My only concern is making sure that I’m not performing too many exercises consecutively that target the same muscle group.  However, a recent study suggested that exercise order could have a profound effect on your workout.

The study analyzed the performance of 29 subjects as they completed a variety of exercises during three sessions.  During the first session, the subjects’ one repetition maximum was determined.  In the second and third sessions, exercises were performed either in small to large muscle order or large to small.  For example, the small to large sequence was: Triceps Extension, Calf Raise, Biceps Curl, Hamstring Curl, Overhead Press, Leg Extension, Rows, Leg Press, and Chest Press.

In addition to collecting data on the blood lactate levels of the subjects throughout the trials, the researchers kept track of the number of repetitions performed as well as how subjects felt after each sequence.

While the differences on blood lactate levels did not differ significantly depending on exercise order, there were important differences in the other two categories.

Subjects performed a greater number of average repetitions when exercises were completed in the small to large order.  This sequence also resulted in more positive feelings both during and ten minutes after the session was over.

But while this method of ordering may be appropriate for one wishing to perform more volume during their workouts, the researchers did note one caveat.  While not explicitly demonstrated in the study, the team suggested that small to large exercise order could potentially result in "decreased force production on large muscle group exercises."

This makes sense, as you will likely be fatigued by the end of your workout.  However, it does not mean that you won’t have a good session, as this order did generate a higher average volume.  It all depends on what your priorities are.  If maxing out your bench press is your primary concern, then you obviously won’t want to tire yourself performing a laundry list of other lifts prior to hitting the bench.

As far as exercise enjoyment, there seemed to be no downside to the small to large exercise ordering.  Through the use of a "feeling scale," the subjects reported improved moods after this sequence, as opposed to the large to small ordering.  What does this mean?  In addition to a "more enjoyable workout," the researchers suggested that this order could improve exercise adherence, meaning that one would be more likely to continue with the exercise program.

This is good news for those regretting a resolution to exercise more; performing exercises in small to large muscle order could be just what is needed to increase enjoyment and make exercise a fun fixture in your routine rather than a torturous task.

Reference: Bellezza, P. et al (2009) The Influence of Exercise Order on Blood Lactate, Perceptual, and Affective Responses. Journal of Strength and Conditioning Research. 23: 203-208.

If you’ve ever had a larger scale binge (think Thanksgiving dinner or a big pasta supper buffet), you might have grown quickly concerned that this was going to lead to a massive weight gain.  But often times it doesn’t.  So, what’s really going on here?  

What determines whether you will gain weight after a period of overeating or not?

This is something that researchers recently looked into to see what all was at play. Here’s what they found out.

The study was designed so a group of 34 male volunteers were fed a weight maintaining diet for four days prior to the study.  

After this period, they were then allowed to select their food from a computerized vending machine that offered a wide variety of foods, after which their 24 hour energy and substrate oxidation rates would be measured.

During the freely chosen meals, the subjects overate by 54 +/- 32% above their maintenance requirements, which resulted in a 1-2 kg body weight gain.  

The interesting thing to note though is that when compared to the baseline diets, the fifth day of the overeating period showed an increase in overall energy expenditure as well as an increase in total carbohydrate oxidation and decrease in fat oxidation.

So, these subjects were ramping up their burning of carbohydrates to mirror the increased incoming intake, while fat oxidation went down.

Protein oxidation remained unchanged during the overfeeding period.

This then suggests that when faced with a very high sudden food increase, the body will adjust its metabolism so that carbohydrate balance in the stores remained under control, while fat was the primary nutrient to go directly into storage during this time period.

The take home message from this then is that if you are going to be overeating, it is better to overeat in strictly carbohydrates, while keeping dietary fat intake as low as possible.  This will cause the body to increase carbohydrate oxidation, but since there will not be incoming fat calories, this will not be converted directly to body fat (as they otherwise likely would be).

While this may not always be 100% practical (try having a very low fat Thanksgiving meal – it would be challenging), when you’re out and are worried that you’re overeating, at the very least try and do your best to keep your selections as low in fat as possible.

Reference:
Larson, DE., et al. (1995) Spontaneous overfeeding with a ‘cafeteria diet’ in men: effects on 24-hour energy expenditure and substrate oxidation. Int. J. Obes Relat. Metab. Disord. May;19(5):331-7.

Using six healthy subjects and a cross over design, researchers had  subjects ingest isomolar amounts of creatine in the amount of 4.4g. Three forms of creatine were used, creatine monohydrate, tri-creatine citrate and creatine pyruvate.  Each subject received each form of creatine with seven days separating each dose.  After the subject ingested the creatine, blood samples were drawn at different time points all the way up to eight hours to measure peak concentrations of creatine following ingestion.

Of the three forms of creatine, creatine pyruvate was the fastest absorbed, followed by tri-creatine citrate, followed by creatine monohydrate.  Would these small differences have any significant impact on muscle creatine concentrations? The researchers stated no, stating creatine monohydrate already has close to 100% bioavailability. Based off this study, it appears that these two other forms of creatine are no more effective than creatine monohydrate, while being more costly.

Jäger R, Harris RC, Purpura M, Francaux M
Comparison of new forms of creatine in raising plasma creatine levels
Journal of the International Society of Sports Nutrition 2007, 4:17 (12 November 2007)

By: ATHLETIC EDGE NUTRITION

If one of your main goals for the coming New Year is to participate in a running event, possibly a half or full marathon, it’s a good idea to consider placing your weight lifting focus on the backburner.

That’s not too say you shouldn’t still lift weights – you should, just that you likely shouldn’t expect to make really great gains while doing so.

First off, you need to realize that many of the hormonal responses that occur in the body after prolonged running takes place are going to be ones that will oppose those of strength training and will not work towards helping you add additional muscle mass.

So, right from the start once you begin doing hour long plus running sessions, you’re going to see side effects.

With a proper diet and enough rest you can help minimize muscle loss while doing your training, but it’s rare to see people doing high volumes of cardio while packing on lean muscle tissue at the same time.

Recently researchers looked at the hormone response that took place after a marathon race in non-elite athletes and their findings help to back these points up.

The researchers drew blood samples one week before a marathon race was to take place, immediately after the race was finished, and then one week after the race was finished and recovery had taken place.

The results of the study indicated that the serum cortisol and prolactin were significantly higher in the time immediately after the race compared to before, but returned back down to more normal levels after the week of recovery had passed.

In addition to this, total testosterone as well as free testosterone also dropped significantly, indicating that this would put the body in a position not conducive to building lean muscle mass (since testosterone is the primary hormone that helps synthesize new muscle tissue).  Again, testosterone levels were returned back to baseline one week after the race too place.

So, the take home message from this is that while marathon training and actually running the race will certainly alter the hormonal profile you experience while training, after you discontinue with that training and move on to more moderate cardio sessions your hormonal profile will return back to normal within a short period of time and you should be able to start making gains with your lean mass building once again (assuming a proper diet is also in line, obviously).

Reference:
Charokopos, N, et al. (2008) Hormonal response to marathon running in non-elite athletes. Eur J Intern Med. Dec; 19(8):598-601.

One habit that many people get into during their workouts, whether it is in between their weight lifting sets or between their sprint intervals is performing static stretches to help keep the muscles lose and prevent muscle soreness.

But, is static stretching really beneficial during your workout? Or does it hinder your performance abilities?

This is what researchers out of the University of Western Australia recently looked at on a study that was designed to examine the effects of static stretching during the recovery periods of field-based team sports with regards to their later sprint performance as well as their ability to change direction while in play.

The study had 12 male participates perform the test on four different occasions.  Each subject began with a standardized warm-up and then followed this with a test to gauge their repeated sprint ability or their change in direction speed.

In both instances they were to perform three sets of six maximal sprint repetitions using a four minute recovery period between sets.

During the break between sets they then either completely rested or else completed a static stretching protocol.  The pattern to test the maximum sprint ability was just a straightforward line sprint while the test to determine their change of direction speed had them alter their direction 100 degrees every four meters for a total of four times.

The results of the study indicated that there was a consistent tendency for the straight line tests to be slower after the static stretching had been performed, while there was not nearly the same effect seen on the change of direction group.

Therefore, from this study we can determine that if you are primarily doing a workout performing straight out running sprints (which is the case for most people when utilizing a HIIT protocol), you’re better off not stretching between your sprint bouts and saving it for later once the workout is finished.

Reference:
Beckett, JR. et al. (2009) Effects of static stretching on repeated sprint and change of direction performance.  Med. Sci. Sports Exercise. Jan 5.

If you’re looking to strip off the final layers of body fat that seem to plague you no matter what you do, there’s good evidence showing that a higher protein, low carb diet is a good way to go.  We already know that out of the three main macronutrients, protein is the one that will boost the metabolism the highest due to the increased calorie burn from digestion (up to 30%), whereas as carbohydrates and fat only cause an about 5 and 2% of the total calories consumed to be burned up through digestion respectively.

In addition to that, protein is also the macronutrient that seems to be the most satisfying, meaning you will have less desire to eat for a longer period of time.  This can also come in handy when trying to maintain a lowered calorie intake when hunger pains would normally beg you to go running to the pantry in search of food.

Recently researchers conducted a study looking at further implications of a high protein diet and found some interesting results.

The objective of the study was to compare the typical hypocaloric diet (15% protein, 30% fat, 55% carbohydrates) with a low-carb, high protein diet consisting of 30% protein, 30% fat, and 40% carbohydrates on the mitrochondrial oxidative metabolism over an eight week period.

The measurements taken for consideration were anthropometric, biochemical variables, resting energy expenditure, as well as mitochondrial oxidation both before and after the study was completed.

The results indicated that the high protein diet produced a greater weight loss than the control diet and along with this, there was also an activation in the mitochondrial oxidation that was found in the high-protein group.

This demonstrates than that the higher protein diet was correlated with a higher final resting energy expenditure and a further decrease in total fat mass.  

So, if you’re looking for an effective way to increase your weight loss, bumping up your protein intake does prove to be an effective method.

Reference:
Abete, I. (2008)  Effects of two energy restricted diets differing in the carbohydrate/protein ratio on weight loss and oxidative changes of obese men.  Int. J. Food Sci. Nutr. Jul 25:1-13.