Carbohydrate performance drinks and 400m sprint performance in women

¶ … consumption of a carbohydrate performance drink increase 400m sprint times?

Carbohydrate loading was found to be beneficial for endurance sports in the late 1990s. Research has demonstrated that consuming high amounts of carbohydrates, combined with low training levels for several days before an event can help to improve performance (Wade, 2008). Since that time, issues have arisen as to which types of carbohydrates are best, which proteins are a factor, and issues regarding gender and differences in metabolism. Results of studies differ in regards to these issues.

The idea that carbohydrate-loading before an endurance event is widely accepted among health and fitness professionals. Now, the food industry has seen the profitability potential in this increased hype about carbohydrate-loading. They have crowded supermarket shelves with performance drinks, performance bars, and powders that can be added to other foods, supposedly to increase performance in sports activities. This research will focus on one particular type of performance drink and will conduct a series of tests to see if using it as directed increases performance in the 400m sprint for women.

Literature Review

The topic of carb-loading and athletic performance has been of interest for several decades. Results of clinical studies generally agree that carb-loading can improve performance in many athletes. However, a number of studies also indicate that this is not always the case. Disagreements exist in the literature as to when and how carbohydrate loading is effective. A literature review was conducted that explored clinical evidence on the topic of carbohydrate loading as well as important studies in the history of the topic. The literature review also explored several topics that were specific to the topic of this research study.

The Basics of Carb Loading

Long before studies on carbohydrate-loading, protein consumption, and energy expenditure during sports was studied by the medical community, the connection between sports performance and nutrition was accepted. Clinical evidence in the area began to mount and the knowledge became more specific. Carbohydrate-loading is a nutritional strategy designed to help store energy in the muscles before an athletic event. Any physical activity requires carbohydrates for fuel. Endurance sports require extra energy so that the athlete does not expend all of their energy and become fatigued. Marathon runners, swimmers, and cyclists who are doing an event that will last 90 minutes are more are considered to benefit from carbohydrate-loading (Mayo Clinic, 2006).

Carbohydrates are the energy that provides the fuel for muscles to contract. Carbohydrates break down into simple sugars, largely glucose, fructose, and galactose. The simple sugars are absorbed in used as energy. If consume more than our body needs at one time it gets stored in the kidneys as glycogen. Once all of the glycogen stores have filled to capacity, the rest is stored as fat. Glycogen stores are used for short, intense exercise such as sprinting adn weight lifting. Glycogen is immediately accessible and is the source of energy for the first few minutes of any exercise. During longer term sports activities glycogen is necessary to help pull fat from the body and turn it into energy (Mayo Clinic, 2006).

The third source of energy is proteins. If the body runs out of carbohydrates and fat, then it begins turning protein into glucose for energy. Proteins are the primary building blocks for the body. They help us to build muscles, bones, skin, hair, and other important body parts. If one exhausts our carbohydrate sources for energy, then the body does not have enough protein to maintain the tissues and they begin to break down. Protein breakdown also creates many by products that do not break down easily, creating kidney stress (Mayo Clinic, 2006).

It is generally accepted that the body begins using glycogen stores after 30 minutes of exercise in that it can continue to use them for up to 90 minutes (DFJDLKJ). Carbohydrates are divided into simple and complex forms. Simple sugars are quickly absorbed and converted to energy. They are the fastest source of energy. Complex carbohydrates take longer to enter the body as they must be digested and broken down first. They provide energy at a slower rate than simple sugars. Foods that contain high amounts of starch and fiber are considered complex carbohydrates, but fiber is not used for energy. Starch is easily broken down and stored as glycogens.

When athletes talk about carb-loading, what they are referring to is storing up carbohydrates using complex carbohydrates such as breads, rice, pasta, cereals, and other grains. Sports drinks and fruits count as simple carbohydrates and are not included in the carb-loading diet of athletes. These are quick energy and are considered the first be burned.

In a clinical study, a high carbohydrate diet was found to have different effects in athletes with differing levels of aerobic capacity. Athletes were divided into several groups. One group trained with carbohydrate-loading, one group trained without carbohydrate-loading, a third group involved untrained athletes with carbohydrate-loading, and the last group was untrained athletes without carbohydrate-loading. Confectionery products were used as a means to supplement normal carbohydrate intake in these trials. The study concluded that this was an effective means for loading carbohydrates to improve performance. It was found that athletes with a lower level of aerobic capacity responded more to carbohydrate-loading than those that had higher levels of aerobic capacity (Sulio, Monda, & Brizzi et al., 1998).

Burke, L., Hawley, J., & Schabort, E. et al. (2000), found that carbohydrate-loading did not improve performance during 100 km cycling events. These authors surmise that perceived benefits of carbohydrate-loading were due to the placebo effect. Carbohydrate-loading did significantly increase muscle glycogen concentrations, but did not result in measurable performance enhancements during the activity.

Gender Differences

Carbohydrate-loading usually entails an intense training to deplete glycogen for two days. This is followed by a glycogen loading of 3 to 14 days which comprises ingesting 60 to 70% of the total energy intake as carbohydrates. However, more recently the glycogen depletion has been eliminated in many programs. In a recent study, it was found that glycogen loading does not have the same affect on males and females. Therefore, the effects of carbohydrate-loading on performance differ as well (Wisman & Willoughby, 2006). Not only does carbohydrate loading effect female athletes differently performance wise, it also affects them in the recovery stage as well. Female athletes had different reactions in terms of metabolic, thermoregulatory, inflammation and the repair processes (Hausswirth & LeMeur, 2011).

Ovarian hormones and the stage in the menstrual cycle were found to be causal in some of the effects found in female athletes. Female athletes tend to demonstrate less capacity to restore normal body temperature after an athletic event than males. They must often take extra measures to return to normal body temperature such as ice water or fans (Hausswirth & LeMeur, 2011). The studies indicate that training and recovery methods should be different for males and females based on physiological reaction during and after athletic activity.

Carbohydrate-loading in men can increase their glycogen levels from between 25 and 100% of the norm (Hausswirth & LeMeur, 2011). In women, carbohydrate-loading may not be as effective. Few studies have examined carbohydrate-loading in women and those that have demonstrated mixed results. It is suspected that women need a higher calorie intake during carbohydrate loading to see the same benefits as men. A woman's menstrual cycle may also have an effect on the efficiency of carbohydrate-loading and glycogen stores. Certain health conditions such as diabetes can also affect the ability to store glycogen during the carbon loading process (Hausswirth & LeMeur, 2011).

Variables that Affect the Efficacy of Carbohydrate Loading on Performance

The proposed study will explore the effectiveness of sports drinks taken by women 2 hours before short duration, intense sporting events. Many women are concerned about losing weight and often fast or engage in low calorie diets. Therefore, it is relevant to explore the affects of fasting on performance after carbohydrate loading. Several studies have also indicated of fat loading can play a role in the effectiveness of carbohydrate loading.

A high fat diet followed by one day of carbohydrate loading was found to increase fat oxidation during a 100 km cycling time trial. However, it compromised high-intensity sprint performance. Researchers suspected that this was possibly due to increased sympathetic activation or altered contractile function (Havermann, West & Goedecke, 2006).

In another stud, the effects of fasting on endurance training vs. consumption of a high fat diet during endurance training were compared. It was found that a high fat, high calorie diet contains sufficient carbohydrates to maintain sufficient glycogen in the muscle during training. It was found that this diet did not impair muscle glycogen breakdown due to exercise (Van Proeyen, Szlufcik, & Nielens, 2011a). The same authors also conducted a study that explored limited carbohydrate availability and training. It was found that consistently training in a fasted state has an effect on muscle metabolism. Fat was found to be more effective than carbohydrates in its ability to increase muscular oxidative capacity. It was further found that fat, but not carbohydrates were important in preventing a drop in blood glucose concentration during fasting exercise (Van Proeyen, Scluficik, & Nielens, 2011b).

Ramadan is a Muslim holiday that involves partial fasting for a long period of time. In a study that examined Muslim men in this fasted state, it was found that subjects in a fed state were able to outperform those in a fasted state in a 1 hour endurance run (Aziz, Wahid, & Prig, 2010). Differences in individuals varied but the differences were significant. The studies demonstrate the effects of fasting on its ability to decrease endurance. High fat diets were found to be more effective in preventing muscle degradation than high carbohydrate diets. The studies will have an impact on the proposed study design, in terms of controlling dietary variables that can affect the outcome.

In a placebo controlled study, athletes were divided into two groups, one of which ingested an amphetamine (methylphenidate) prior to exercise performance. Subjects who took the amphetamine were able to cycle 32% longer before their output fell to 70% of the starting value. Those receiving the amphetamine had significantly higher oxygen consumption, heart rate, and blood lactate concentrations. Amphetamines resulted in cyclers who could exercise longer. Muscle fatigue was the main factor that caused the athletes to discontinue exercising, regardless of the group they were in (Swart, Lamberts, Lambert, 2009b). This research demonstrates the ability of drugs to influence the outcome of research studies involving carb-loading.

Training Regimes and theories differ significantly in the literature. In a study that examined training daily and training twice every second day, the ability to engage in high-intensity training was compromised in the every second day training schedule. However, there was little change in time trials using either training method (Yeo, Paton, & Garnham, 2008). This is only one of many studies that examines the effect of training schedules and methods on performance. In terms of the proposed research study, it highlights the importance of selecting a consistent training schedule for all participants.

Perceived exertion perceptions also affect performance. During maximum effort time trials, feedback was withheld until the final kilometer. This study found that when athletes are certain about the endpoint of the exercise, they are more aggressive and achieve higher performance. They are able to apply strategies that help them to improve performance. Uncertainty about the endpoint of the exercise decreases performance and increases perceived exertion (Swart, Lamberts, & Lambert, 2009).

Rationale

A literature review revealed that there are many gaps in research concerning athletic performance in the factors that affect it. This research will fill one small gap in sports nutrition and medicine. The aim of this study will not be to support or dispute claims by a manufacturer, but rather to examine the effects of sport drinks as a whole. However, the use of a single sports drink will serve the purpose of eliminating a confounding variable from the study due to variability in sports drink content. This study will fill the gap in the literature concerning the effectiveness of sports drinks consumed 2 hours before an athletic event.

This study method chosen will be similar to other studies found during the literature review. The study design will address design issues that were found in the other studies, such as the presence of conditions that could interfere with the results. One of the most difficult aspects of the study will be to eliminate the presence of placebo affect from the study groups. The placebo affect is a common difficulty to overcome in many clinical studies. This issue is difficult to resolve in a single study and often requires repeat performances of the study to eliminate the possibility that placebo effect was responsible for the results obtained.

The study procedure involves selection of 20 female athletes between the ages of 18 and 22. The participants will be selected from a group of volunteers from a local university. All of the volunteers will be involved in some type of track and field sport. The 400m sprint is the longest of the competitive sprints. It requires greater endurance and stamina to maintain maximum effort for the entire distance. The athletes will be divided into two groups. Both of the groups will perform the 400m sprint for five trials and their scores will be recorded.

They will then enter into a six-week training program where they will all receive the same training schedule and will follow a prescribed diet. At the end of the six-week period another trial of the 400m sprint will be performed. Two hours before the prescribed trial, one group will consume a 12 oz bottle of Gatorade performance, then both groups will perform another 400m sprint for five rials. Baseline scores at the beginning of the study will be compared to the second trial. The dependent variable will be measured using differences in the pre-test and post-test scores of individuals.

The rationale for this study is based on standard empirical methods using the test group and a control group. The addition of a standardized training and diet regime will be used to eliminate variables that could confound the results of the study. The purpose of the standardized program is to help isolate the dependent variable to the greatest extent possible. Athletes in both groups will be asked to refrain from taking any medication that could affect their performance prior to the pre-test and post-test. They will also be asked to get a good night's sleep and to avoid fasting during the course of this study. The rationale for these measures is based on factors identified during the literature review that could affect the performance of the athletes.

Hypothesis

This study hypothesis will state, "Athletes that consume a 12 oz sports drink will demonstrate improvement in 400m sprint times, as compared to a group that does not consume a sports drink prior to the event."

Aims and Objectives

The hypothesis for the study can be misleading in its simplicity. It would be easy to extrapolate the success or failure of sports drinks and its ability to improve performance based on this study. It would be specifically tempting to support or choose not to support the particular drink used in the study. However, this is not the aim of the study. The aims and objectives of the study go beyond the sports drink. This sports drink chosen for this study was selected due to its nutrition content, particularly carbs, protein, and simple sugar content. The sport's ring chosen represents nutrient loading 2 hours before the event. The aim of the study is to examine the effects of short-term carb loading just prior to an event.

The literature review found that carb-loading for two or three days prior to an endurance event was effective in increasing performance. However, the literature also indicated that carb-loading for several days prior to a short-term, high-intensity event had little affect on enhancing performance. This study will take a different angle from both of these studies. It will examine the effects of short-term carb-loading right before a short-term, high-intensity event. This study will examine whether the timing and type of carb-loading will have an affect on performance in short-term, high-intensity events.

The objectives of the study will include the following:

1. To examine the effects of sports drinks on performance during short-term, high-intensity sports events.

2. To examine whether the type in timing of carb-loading before an event has an effect on performance.

3. To devise a method for eliminating confounding variables that were found to be problematic in previous research studies.

Appendix A.

Does the consmption of a carbohydrate performance drink increase 400m sprint times?

Subjects:

who?

Recruitment?

How many?

Limitations?

Exclusion criteria

Female Athletes 18-22 years old

Local University track and field Team -- personal contact

20

Yes.

Don't know variability -- maybe should do pilot study

Medical conditions

Diabetes

Asthmatics

Heart Conditions

Any other medical condition that precludes them from participation

Restriction from the activity by a doctor due to prior injury

Treatments

12 ounce bottle of Gatorade Performance

Design

10 subjects in each of 2 treatments

Double blind

Measurement 1

Why?

How?

Reliability?

Validity?

Limitations to study?

400m Sprint times

This will be the primary measurement

Standard stopwatch

Good -- accurate to .01 second.

Standard method for recording times.

The elimination of placebo effect could be problematic

Measurement 2

Why?

How?

Reliability?

Validity?

Limitations to study?

400m Sprint times

This will be the primary measurement

Standard stopwatch

Good -- accurate to .01 second.

Standard method for recording times.

The elimination of placebo effect could be problematic

Ethical issues

Need informed consent