Max or Submax- That is the Question

When performing a VO2 max test it can be difficult to determine whether or not true, maximal oxygen consumption was attained. Historically VO2 max tests require the subject to run on a treadmill as long as they can and the amount of oxygen consumed in the last minute of the test is considered the VO2 max. This method often yields sub maximal scores. Physiologically there are four ways to determine whether maximal oxygen consumption has been reached.

1.       No increase in oxygen consumption with an increase in workload (plateau)

2.       Obtaining max HR

3.       RER > 1.1

4.       Blood lactate concentration above 8 mM

At least one of these must occur for a VO2 max test to be considered valid. One must be careful in measuring these criteria, particularly maximal heart rate. Simple formulas like (220-age yrs) are inaccurate and should be taken with a grain of salt.

VO2 Max: Falling Short of The Hype-rventilation

The VO2 max test is considered by many (myself excluded) to be the gold standard human performance test. It has been largely popularized by the Gatorade add campaign that ran in the early 2000’s featuring beautiful female athletes and well branded male athletes performing maximal treadmill tests. Additionally, during Lance Armstrong’s long reign over the peloton it was well documented that Lance had performed a VO2 max test with a score of 86 ml/kg/min. Naturally an extremely high VO2 max became directly associated with elite aerobic performance. This week I will be posting the 4 reasons the VO2 Max Test isn’t all its hyped up to be. Topics I will address include:

1.       It’s difficult to know if you are actually measuring a subjects maximal oxygen consumption

2.       The VO2 max test downplays the importance of bio-mechanical efficiency

3.       The VO2 max test downplays the importance of having a high lactate threshold

4.       The formulas used to determine caloric expenditure are poorly validated

Four Tips for Better Academic Research Presentations

          Have you ever wondered how professors and other researchers are so good at making convincing presentations out of relatively insignificant data? Last semester I was in charge of a research study that yielded seemingly insignificant results. With my tail between my legs I presented the results to the professor that I work under. In about twenty minutes he re-ran the SPSS statistical reports and had signed me up to present at the ACSM regional conference.  As it turns out I had been approaching the data from the wrong angle.  I am currently in my final semester of graduate school and am finally beginning to pick up on a few “tricks of the trade”. 

1.      Don’t Be Afraid to Turn a Large Study Into Several Smaller “Cohort Studies”

For example, one could set up a product validation study with 100 random participants. If the results are classified as insignificant you could break up the data into cohorts like: post menopausal women, college aged men, college aged obese females etc. You may find that there is a strong correlation in one of these groups.

2.       Save the Pies for Dessert

Another presentation technique I have learned is the art of using graphs. Great researchers ALWAYS use the proper graph. Just because Microsoft Excel allows you to turn one group of data into any type of graph doesn’t mean proper graph selection is unimportant. Steven Phew is considered by many to be the world’s leading expert on graph selection and he has written numerous publications on graph types and color scheme optimization. In his most famous publication, “Save the Pies for Dessert” Steven cautions readers to not use pie graphs. Additionally, he suggests that 3D bar graphs are confusing and misleading.

3.      Thoughtfully Scale your Graphs

First, you must carefully determine how you will label your axes to convey your point to the audience.  After you have labeled your axes you must determine which units you will use on each axis. Then you must decide how you will scale your axes. The following graphs illustrate the importance of proper scaling.

(Indicates Insignificant Difference)

(Indicates Significant Difference)

4.      No Significance can be Extremely Significant

The purpose of most intervention studies is to “prove” that a given stimuli either positively or negatively effects a person. Generally when data that has no statistical significant is frowned upon. Don’t down play the fact that you have just “proven” that a stimulus has no measurable effect on a person. These results are still valid and could be useful. Great presenters are able to turn nominally important data into home run presentations.

ABOUT THE AUTHOR

            Will Hawkins is the President of Will Hawkins Consulting LLC a company that provides cutting edge research collection and presentation packages for health and wellness companies of any size. Learn more about his company at www.willhawkinsconsulting.com or email him personally at will@willhawkinsconsulting.com.

The Cure to Cycling Induced Erectile Dysfunction

The Case for a Vibrating Saddle

            The Following is a research project I recently did on Cycling Induced Erectile Dysfunction. It not only describes the mechanism by which cycling induced erectile dysfunction occurs but it also explores a possible solution to the problem

            Cyclists perhaps more than other athletes have cause for concern with regards to lower extremity blood flow. Because cycling is a sport that depends largely on the aerobic energy system, must be readily available. Aerobic performance isn’t the only reason that cyclists require blood flow to the lower extremity. It is well documented that endurance cyclists often suffer from erectile dysfunction and decreased potency due to prolonged periods of decreased penile blood flow (Bressel, Reeve, Parker, & Cronin, 2007) (Spears et al., 2003). Additionally, there have been reports of severe, acute penile pain during endurance cycling events (Desai & Gingell, 1989). All of these ailments stem from hypoxia due to lack of blood flow in the lower extremity.

             Oxygen’s bioavailability is not only limited by the typical physiological limiting factors of  like the partial pressure of oxygen ( ) (Allen & Jones, 1984) and the affinity or strength of the bond between oxygen and hemoglobin (Anderson & Kippelen, 2005). There are cycling specific mechanical limiting factors involved as well. The most well studied of these mechanical factors is that cyclists are seated on a relatively small and firm saddle. The pressure from this saddle causes compression of the lower body’s blood supply (Bressel, et al., 2007) leading to loss of blood flow to the lower extremity (Mayrovitz, Delgado, & Smith, 1998). It appears that the dimensions as well as the rigidity of the saddle combined with saddle alignment on the seat post can minimize the negative effects of this compression, increasing blood flow to the lower body (Jeong, Park, Moon, & Ryu, 2002).

            One of the less studied mechanical factors contributing to change in localized blood flow is vibratory force. It has been documented that vibratory force has an effect on skeletal muscle blood flow (Kerschan-Schindl et al., 2001; Yamada et al., 2005) (Herrero et al., 2011). A team of researchers at the British Olympic Medical Institute published that they suggest two minutes of vibration platform warm up before every workout (Cardinale, Ferrari, & Quaresima, 2007). Not only is there an increase in blood flow to skeletal muscle but there is a corresponding increase in due to increased neuromuscular and metabolic activity (Rittweger et al., 2002) (Rittweger, Schiesel, & Felsenberg, 2001). Additional positive training responses that have been theorized with vibratory exercise include: soft tissue fiber realignment due to a mechanically induced massage, increases in maximal anaerobic power output and increase in maximal vertical leap. The latter two responses are believed to be caused by muscle spindle and Golgi tendon organ deactivation causing a decrease in mechanoreceptor inhibition. This in effect maximizes the stretch shortening cycle (Fallon & Macefield, 2007; Issurin, 2005) (Giszter & Kargo, 2002).

            Vibration is however a double edged sword. The amount of vibration experienced, generally measured in Hz, determines the effect the vibration will have on blood flow. For example, compared to the non-vibration bouts, frequencies of 10-30 Hz increased mean blood cell velocity by approximately 33% (P<0.01) whereas 20-30 Hz increased peak blood cell velocity by approximately 27% (Lythgo, Eser, de Groot, & Galea, 2009) (Kerschan-Schindl, et al., 2001) Vibration doses smaller than 10 Hz have been shown to have very little effect and large doses of vibration have an inverse effect on blood flow. (Lythgo, et al., 2009).

            In the clinical setting, vibration is produced one of two ways. It is produced either  through contact with a hand-held vibrating bar or rail, (Issurin & Tenenbaum, 1999) or by having the subject sit or stand on a vibrating platform (Rittweger, Beller, & Felsenberg, 2000). Currently, there are two types of vibration platforms available on the market. A platform that moves or oscillates in a vertical direction (fixed frequency and amplitude), and a platform that rotates about a fixed horizontal axis (variable frequency and amplitude) (Lythgo, et al., 2009). When trying to mimic the vibratory force experienced by a cyclist, the force plate is more practical.

            In order for one to clinically test the effects of vibration on cyclist one would need to carefully mimic the types of vibration experienced by cyclists. One could mount a bicycle on a vibration platform and use a Doppler blood flow unit to measure blood flow with and without vibration. However, without the proper direction of oscillation, frequency and amplitude the results would mean nothing. Additionally, the amount of vibration experienced at the point of contact between the bicycle and the road will be significantly higher than what the rider is experiencing in the saddle. This indicates that the bicycle frame will have a huge effect on vibration absorption and transmission. As with any potential “first time” study it probably wouldn’t be perfect but it would get the ball rolling on a new idea to be researched. 

ABOUT THE AUTHOR

            Will Hawkins is the President of Will Hawkins Consulting LLC a company that provides cutting edge research collection and presentation packages for health and wellness companies of any size. Learn more about his company at www.willhawkinsconsulting.com or email him personally at will@willhawkinsconsulting.com.

Allen, C. J., & Jones, N. L. (1984). Rate of change of alveolar carbon dioxide and the control of ventilation during exercise. [; Research Support, Non-U.S. Gov't]. J Physiol, 355, 1-9.

Anderson, S. D., & Kippelen, P. (2005). Exercise-induced bronchoconstriction: pathogenesis. [; Review]. Curr Allergy Asthma Rep, 5(2), 116-122.

Bressel, E., Reeve, T., Parker, D., & Cronin, J. (2007). Influence of bicycle seat pressure on compression of the perineum: A MRI analysis. [Article]. Journal of Biomechanics, 40(1), 198-202. doi: 10.1016/j.jbiomech.2005.11.017

Cardinale, M., Ferrari, M., & Quaresima, V. (2007). Gastrocnemius medialis and vastus lateralis oxygenation during whole-body vibration exercise. [Article]. Medicine and Science in Sports and Exercise, 39(4), 694-700. doi: 10.1249/mss.0b013e31803084d8

Desai, K. M., & Gingell, J. C. (1989). HAZARDS OF LONG-DISTANCE CYCLING. [Article]. British Medical Journal, 298(6680), 1072-1073.

Fallon, J. B., & Macefield, V. G. (2007). Vibration sensitivity of human muscle spindles and Golgi tendon organs. [; Research Support, Non-U.S. Gov't]. Muscle Nerve, 36(1), 21-29.

Giszter, S. F., & Kargo, W. J. (2002). Separation and estimation of muscle spindle and tension receptor populations by vibration of the biceps muscle in the frog. [; Research Support, U.S. Gov't, P.H.S.]. Arch Ital Biol, 140(4), 283-294.

Herrero, A. J., Martin, J., Martin, T., Garcia-Lopez, D., Garatachea, N., Jimenez, B., & Marin, P. J. (2011). Whole-body vibration alters blood flow velocity and neuromuscular activity in Friedreich's ataxia. Clin Physiol Funct Imaging, 31(2), 139-144.

Issurin, V. B. (2005). Vibrations and their applications in sport. A review. [; Review]. J Sports Med Phys Fitness, 45(3), 324-336.

Issurin, V. B., & Tenenbaum, G. (1999). Acute and residual effects of vibratory stimulation on explosive strength in elite and amateur athletes. [Clinical Trial; ; Randomized Controlled Trial]. J Sports Sci, 17(3), 177-182.

Jeong, S. J., Park, K., Moon, J. D., & Ryu, S. B. (2002). Bicycle saddle shape affects penile blood flow. [Article]. International Journal of Impotence Research, 14(6), 513-517. doi: 10.1038/sj.ijir.3900929

Kerschan-Schindl, K., Grampp, S., Henk, C., Resch, H., Preisinger, E., Fialka-Moser, V., & Imhof, H. (2001). Whole-body vibration exercise leads to alterations in muscle blood volume. Clin Physiol, 21(3), 377-382.

Lythgo, N., Eser, P., de Groot, P., & Galea, M. (2009). Whole-body vibration dosage alters leg blood flow. Clin Physiol Funct Imaging, 29(1), 53-59.

Mayrovitz, H. N., Delgado, M., & Smith, J. (1998). Compression bandaging effects on lower extremity peripheral and sub-bandage skin blood perfusion. Ostomy Wound Manage, 44(3), 56-60, 62, 64 passim.

Rittweger, J., Beller, G., & Felsenberg, D. (2000). Acute physiological effects of exhaustive whole-body vibration exercise in man. Clin Physiol, 20(2), 134-142.

Rittweger, J., Ehrig, J., Just, K., Mutschelknauss, M., Kirsch, K. A., & Felsenberg, D. (2002). Oxygen uptake in whole-body vibration exercise: Influence of vibration frequency, amplitude, and external load. [Article]. International Journal of Sports Medicine, 23(6), 428-432.

Rittweger, J., Schiesel, H., & Felsenberg, D. (2001). Oxygen uptake during whole-body vibration exercise: comparison with squatting as a slow voluntary movement. [Article]. European Journal of Applied Physiology, 86(2), 169-173.

Spears, I. R., Cummins, N. K., Brenchley, Z., Donohue, C., Turnbull, C., Burton, S., & Mach, G. A. (2003). The effect of saddle design on stresses in the perineum during cycling. [Article]. Medicine and Science in Sports and Exercise, 35(9), 1620-1625. doi: 10.1249/01.mss.0000084559.35162.73

Yamada, E., Kusaka, T., Miyamoto, K., Tanaka, S., Morita, S., Tanaka, S., . . . Itoh, S. (2005). Vastus lateralis oxygenation and blood volume measured by near-infrared spectroscopy during whole body vibration. [Clinical Trial; ; Research Support, Non-U.S. Gov't]. Clin Physiol Funct Imaging, 25(4), 203-208.

Bioenergetics Part 1: Creatine Phosphate

Bioenergetics is a field of biochemistry that explains how the body converts energy into a usable form to accomplish mechanical work. Notice I didn’t say that the body creates energy for mechanical work. According to the First Law of Thermodynamics, no energy is ever created or destroyed. All of the energy that we are able to convert to usable energy forms comes from the sun and enters our body through eating, drinking and breathing. The body has four primary ways of producing ATP (fuel for mechanical work), and over the next month or so I will be writing a post about each. First up is the ATP-Pc energy system.

So right off the bat we need to get some vocabulary straight. Adenosine Triphosphate (ATP) is to the human body what gasoline is to the car. ATP interacts with myosin which attaches to the actin filament causing contraction. Once this contraction occurs the ATP becomes ADP, because it loses a phosphate in the contraction process. So this ADP can’t be used for contraction again until phosphorylation occurs (the addition of a phosphate). This is where the energy systems come into play.

The Creatine Phosphate energy system is an anaerobic energy system and is the first energy system used during maximal work. It is the fastest energy system because it requires only one chemical reaction to produce an ATP. A molecule of Phosphocreatine (Pc) meets up with a molecule of ADP and the enzyme Creatine Kinase causes the phosphate group bonded to creatine to join the ADP molecule. This makes ATP and leaves a creatine molecule.  Pretty simple, right? Your body can use the ATP-Pc energy system to produce roughly ten seconds of maximal work, and in about 2 minutes, it’s ready to yield another ten seconds of maximal work. Think of this energy system as a toilet. Once you pull the lever it takes about 10 seconds to flush all the water, and then it takes about two minutes for the tank to refill to allow for another flush. If you were to flush before the tank was entirely full, you would empty the tank, but it wouldn’t take 10 seconds to empty this time. The same is true for the phosphor creatine system. Fortunately, after the initial ten seconds of work, anaerobic glycolysis is ready to kick in and pick up the slack. We will talk about anaerobic glycolysis next time.

So now that the Creatine Phosphate energy system has been explained (hopefully), I would now like to talk about creatine supplementation. Anyone who has ever flipped through the pages of a Muscle and Fitness/Fiction magazine has heard boisterous claims of the unregulated supplement industry concerning creatine. For your pleasure/laughter (mostly the latter), I have compiled some of the more humorous product claims that I was able to come across on a recent trip to the GNC and have posted them at the bottom of this article. While there is a lot of ridiculous hype that comes with creatine supplementation, there is no denying that the stuff works. By boosting the amount of creatine stored in the body, the proverbial toilet tank begins to hold more water (produce more ATP) before it needs to be refilled. Wichita State University has been on the cutting edge in researching the effects of creatine supplementation in the elderly, and in a recent study they found that old people who were taking creatine and working out averaged 15% more strength gains than groups using the same workout protocol but not supplementing with creatine. This same study has been done on athletes and other people and has been substantiated over and over. 

So some of you might be thinking, “Why should I care about energy systems?” I reply with an equally thoughtful question (like Socrates). How do you feel about rigor mortis? Not only do your muscles need ATP to contract a muscle, but ATP is also needed to return the muscle to its resting length. This, coupled with the fact that at any given moment your body has only enough ATP to keep you alive for 2-3 seconds, should be enough to convince you that knowledge of energy systems is important. Thank you for your readership, and please comment if you have any questions, comments, concerns or rebukes.

“947% increase in lean mass” – Gaspari Nutrition, Super Pump 250

“234% increase in muscle performance” –Gaspari Nutrition, Super Pump 250

“26 times more lean muscle mass than those who use creatine monohydrate alone”- Cell Tech Hardcore

“148.65% increase in muscle DNA”- NO Shotgun

- Will Hawkins 

Rogers, Michael E., and Ruth M. Bohlken. "EFFECTS OF CREATINE, GINSENG, AND ASTRAGALUS SUPPLEMENTATION ON STRENGTH, BODY COMPOSITION, MOOD, AND BLOOD LIPIDS DURING STRENGTH-TRAINING IN OLDER ADULTS." Journal of Sports Science and Medacine 5.1 (2006): 60-69. Print.

Howley, Edward T., and Scott K. Powers. Exercise Physiology: Theory and Application to Fitness and Performance. 7 ed. New York: McGraw-Hill, 2008. Print.