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Isotonic Sports Drinks
The comparison between commercially branded and a homemade sports drink and the different effects that they have on sports performance, relating to aerobic exercise.
Hannah V. Cox
Flat 2 46 Woodlane Falmouth Cornwall TR11 4QZ Telephone: 07512626577 Email: hannah_cox1990@live.co.uk
Isotonic Sports Drinks
ABSTRACT The reason behind this study was to research and examine two carbohydrateelectrolyte sports drinks; one a commercial brand and the other a homemade supplement.
The comparison of these drinks effects would then be measured
through time, heart rate (HR) and rate of perceived exertion (RPE) on six male subjects, all with the same sports background and lifestyle. The drinks were then compared on three separate occasions containing 500ml of fluid for each, whilst introducing water for the start point and the minimum amount that an individual can use as a hydrative aid whilst, aerobically exercising through rowing. Data samples were then collected for every five hundred meters of a five kilometer testing period. Form the results that were produced it showed that there were no significant differences between the sports drinks times and RPE but the mean for HR on the homemade product, did have a distribution difference which indicated that the subject’s HR’s were lower when testing this drink providing information that they did not have to work as hard. This correlation meant that when referring to time where there were no significant differences, proves that for both drinks they exercised for near enough the same length of time but with the commercial drink being physically more demanding than the other. To conclude this study these results have shown that the samples sizes of the data collections were too small and that a significant difference could not be determined, leaving both of the drinks to be beneficial on sports performance. Key words; Carbohydrate-electrolytes, rowing, hydration.
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Isotonic Sports Drinks
INTRODUCTION Sports drinks were primarily produced with the aim to appeal to the sports target audience. With the increasing popularity for these drinks they have branched out to becoming commercially recognisable with the general public and sport participators. Due to the popularity of certain brands, these branded products have managed to create their own industry. It’s these commercially accessible branded products such as the likes of Lucozade Isotonic Sports Drinks that aim to improve sports performance by promising to reduce the onset of muscular fatigue, and restore electrolytes lost through perspiration, to improve endurance capacity (1, 4, 10). Isotonic sports drinks undoubtedly provide a sufficient formula to improve sports performance over prolonged periods of time with an aim from a study of Khanna and Manna (3) that non-supplementation to those containing a mixture of carbohydrateelectrolytes had any effect on correlation between heart rate responses (HR) during a Vo2 max test. The question addressed is whether there is at least a comparison or difference in effects between an isotonic commercially branded sports drink and a homemade isotonic sports drink on sports performance, in relation to aerobic exercise. It’s recommended by various studies that the easiest way to differentiate whether different sports drinks have influences on sports performances is to measure the averages of a subjects time taken, to complete the aerobic exercise in task. Ostojic and Mazic (7) provide information that this form of measurement can execute clear results and works well with the rate of perceived exertion (RPE) and HR. Leading to building a relationship between how hard a subject, perceives they are working and how hard they physiologically are working in accordance to any data collected.
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Isotonic Sports Drinks Though commercially branded products have become successful overtime it’s common knowledge through research of Shirreffs (10) and Coombes (2) that the ingredients used are less than traditional with the wide varieties of different forms of; proteins, carbohydrates, fats and nutrients. Where the homemade sports drinks can pride themselves in eliminating and controlling the amount of substances placed within the fluid contents (8). Taking this information the purpose of the investigation will be to extend the knowledge of this interest to examine whether testing the two drinks mentioned against each other, will show at least a difference in sports performance whilst being measured with the above methods of time, HR and RPE.
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Isotonic Sports Drinks
METHODS Subjects This study involves six males between the ages of twenty and twenty-three years of age who all share the same sporting background of rugby, and regularly participate in training up to four times a week. Prior to the start of testing all subjects were briefed about the expected distance of five kilometers needing to be covered and a written consent form was signed as well as a Performance Activity Readiness Questionnaire (PARQ) to volunteer as subjects to take part in the following testing. All subjects consisted of the same health and lifestyle to eliminate any pending variables. Experimental procedures All subjects were informed to attend the gym on three different dates at the same time to participate in the upcoming testing’s consisting of five day intervals between each. On the separate testing dates the three different drinks are aimed to be consumed with measurements of 500ml for each. The first to be tested would be the Lucozade Sport, the second the homemade drink and the third involving just plain water. Before this could happen each of the hydro packs that the subjects would have to wear would need to be filled and ready containing the specified drink needed for that test on the day. When it would finally come to testing the homemade sports drink a mixture consisting of 100ml squash, 100ml of plain water, 30g sugar and a pinch of salt would be put together (5). To allow all results to be as valid as possible participants were advised to not consume any products based with high amounts of caffeine, glucose or alcohol
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Isotonic Sports Drinks
twenty-four hours before the start of testing on all three occasions (3). As well as advising the subjects on nutritional aspects, hydration levels prior to the testing would need to be mentioned as this is detrimental to any data to be collected. It’s suggested that each subject would need to consume 600ml of fluid (plain water) four hours prior and 240ml, ten to fifteen minutes before proceeding to the test (8). Whilst advising the six subjects about nutritional recommendations they were also informed about the BORG scale (scale of 6-20) otherwise known as the Rate of Perceived Exertion (RPE). The scale was shown to the group and explained of how it worked and the point being behind it, that they would need to tell the individual monitoring them their perception of how hard they believed they were exerting themselves. The subjects were then handed a copy of the scale and each told to become familiar with it beforehand. On the day of the first test subjects arrived and took part in a ten minute warm up containing stretching and light rowing, before going on to be fitted with equipment such as hydro packs and pulse rate monitors (Cateye PL-6000). Once all equipment was shown as functional the subjects took to the indoor rowing machines (Concept 2) and the total distance to be rowed of five kilometers was entered. Whilst rowing subjects were expected to maintain hydration levels throughout by consistently drinking from the hydro packs until the full contents of 500ml had been emptied. At set points of 500 meters during the rowing distance the subject’s HR, RPE and time were taken. After the first test the protocol was copied exactly the same but replaced with a different drink each time with none of the subjects knowing which out of the two sports drinks were to be tested next. This was carried out until all three tests had
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Isotonic Sports Drinks
been completed and data had been collected. Then reduce any risk of injury subjects were recommended to do a ten minute cool down of light exercise. Statistical Analyses A paired t-test analysis was carried out to calculate the data collected with the degrees of freedom being used at industry level of p ≤ 0.05. The paired t-test was repeatedly used on all comparisons of each individual drink being tested.
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Isotonic Sports Drinks
RESULTS The following results below show the statistical analysis for the Lucozade sports drink (drink1) and the Homemade sports drink (drink 2). For each of the statistical figures the following measurements of time, HR and RPE have been represented.
Paired t Test for the Mean time of Lucozade and the Homemade Drink Summary Report Do the means differ? 0
Paired Differences *
Statistics
0.05 0.1
> 0.5
Yes
No P = 0.084 The mean of Lucozade is not significantly different from the mean of Homemade (p > 0.05).
Sample size Mean 95% CI Standard deviation
10 8.1 (-1.3269, 17.527) 13.178
* The difference is defined as Lucozade - Homemade.
Mean Standard deviation
Lucozade
Homemade
150.2 15.612
142.1 10.137
Distribution of the Differences Where are the differences relative to zero? Comments
0
Test: There is not enough evidence to conclude that the means differ at the 0.05 level of significance. CI: Quantifies the uncertainty associated with estimating the difference from sample data. Showing that it can be 95% confident that the true difference is between -1.3269 and 17.527.
-10
0
10
20
30
Distribution of differences: Compare the location of the differences to zero.
Figure 1; Mean times for both the Lucozade and the Homemade sports drink to show the distribution of differences.
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Isotonic Sports Drinks
Paired t Test for the Mean Time of Lucozade and the Homemade Drink Diagnostic Report Paired Data in Worksheet Order
180
Lucozade Homemade
160
140
What difference can you detect with a sample size of 10? Difference Power
Power What is the chance of detecting a difference? < 40%
60%
90%
100%
10.343 11.623 13.125 15.215
10.343 15.215 For alpha = 0.05 and sample size = 10: If the true means differed by 10.343, you would have a 60% chance of detecting the difference with a paired test. If they differed by 15.215, you would have a 90% chance.
60.0 70.0 80.0 90.0
Power is a function of the sample size and the standard deviation. To detect a difference smaller than 13.125, consider increasing the sample size.
Figure 2; Differences with both sports drinks when testing mean time.
Paired t Test for the Mean HR of Lucozade and the Homemade Drink Summary Report Do the means differ? 0
0.05
Paired Differences *
Statistics
0.1
> 0.5
Yes
No
P = 0.000 The mean of Lucozade is significantly different from the mean of Homemade (p < 0.05).
Sample size Mean 95% CI Standard deviation
10 6.8 (4.2585, 9.3415) 3.5528
* The difference is defined as Lucozade - Homemade.
Mean Standard deviation
Lucozade
Homemade
173.8 9.7957
167 8.4984
Distribution of the Differences Where are the differences relative to zero? Comments
0
Test: You can conclude that the means differ at the 0.05 level of significance. The mean of the paired differences is greater than zero. CI: Quantifies the uncertainty associated with estimating the difference from sample data. Showing it to be 95% confident that the true difference is between 4.2585 and 9.3415. Distribution of differences: Compare the location of the differences to zero. 0.0
2.5
5.0
7.5
10.0
Figure 3; Mean HR of both the Lucozade and Homemade sports drink to show the distribution of differences.
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Isotonic Sports Drinks
Paired t Test for the Mean HR of Lucozade and the Homemade Drink Diagnostic Report Paired Data in Worksheet Order Lucozade Homemade
180
170
160
150
What difference can you detect with a sample size of 10? Difference Power
Power What is the chance of detecting a difference? < 40%
60%
90%
100%
2.7885 3.1336 3.5386 4.1019
2.7885 4.1019 For alpha = 0.05 and sample size = 10: If the true means differed by 2.7885, you would have a 60% chance of detecting the difference with a paired test. If they differed by 4.1019, you would have a 90% chance.
60.0 70.0 80.0 90.0
Power is a function of the sample size and the standard deviation. To detect a difference smaller than 3.5386, consider increasing the sample size.
Figure 4; Differences with both sports drinks when testing mean HR.
Paired t Test for the Mean RPE of Lucozade and a Homemade Drink Summary Report Do the means differ? 0
0.05
Paired Differences *
Statistics
0.1
> 0.5
Yes
No P = 0.051 The mean of Lucozade is not significantly different from the mean of Homemade (p > 0.05).
Sample size Mean 95% CI Standard deviation
10 -0.6 (-1.2032, 0.0032419) 0.84327
* The difference is defined as Lucozade - Homemade.
Mean Standard deviation
Lucozade
Homemade
12.3 3.6530
12.9 4.1753
Distribution of the Differences Where are the differences relative to zero? 0
Comments Test: There is not enough evidence to conclude that the means differ at the 0.05 level of significance. CI: Quantifies the uncertainty associated with estimating the difference from sample data. Showing it to be 95% confident that the true difference is between -1.2032 and 0.0032419. Distribution of differences: Compare the location of the differences to zero.
-2.0
-1.5
-1.0
-0.5
0.0
Figure 5; Mean RPE of both the Lucozade and Homemade sports drink to show the distribution of differences.
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Isotonic Sports Drinks
Paired t Test for the Mean RPE of Lucozade and a Homemade Diagnostic Report Paired Data in Worksheet Order
20
Lucozade Homemade
15
10
Power What is the chance of detecting a difference? < 40%
60%
90%
100%
0.66186 0.97361 For alpha = 0.05 and sample size = 10: If the true means differed by 0.66186, you would have a 60% chance of detecting the difference with a paired test. If they differed by 0.97361, you would have a 90% chance.
What difference can you detect with a sample size of 10? Difference Power 0.66186 0.74379 0.83990 0.97361
60.0 70.0 80.0 90.0
Power is a function of the sample size and the standard deviation. To detect a difference smaller than 0.83990, consider increasing the sample size.
Figure 6; Differences with both sports drinks when testing mean RPE.
The results of Figure (1) show that there was not enough evidence to conclude a significant difference to the means of the data due to small sample sizes. Whereas HR means Figure (3) provide evidence that the means differ at 0.05. Similar to the results of time (Figure, 1) the results in Figure (5) provide sufficient evidence that there is not enough difference between the two samples.
Isotonic Sports Drinks
DISCUSSION The purpose of this investigation has lead its way in to producing numerous results, with all of them having the aim of comparing separate drinks against one another in order to provide sufficient evidence, if whether the drink labeled Homemade had any effects that could suggest it at least had an equal effect or more on improving sports performance. After putting the majority of sample data through statistical analysis it provided information that showed there was not enough evidence to conclude to there being a significant difference between various methods of measurement. The first piece of data to be discussed through this will be time. Time was used as the main form of measurement due to commercial brands highlighting their products such as sports drinks and isotonic sports drinks, in particular for producing enough energy and supplementation to replace any that is lost through perspiration (1, 4, 9). The fact that there was not enough evidence to conclude if the Homemade drink improved sports performance over the Lucozade was due to their only being a sample size of ten, where a measurement was taken at every five hundred meters until it reached the total amount of five kilometers. From the information presented in figures 1 and 2 it showed that if there was a larger sample size which consisted of taking a measurement at every one hundred meters there would be sufficient evidence that one of the drinks tested, would of had an effect on sports performance whilst participating in endurance rowing. Though time was not proven as a sufficient method of depicting whether there was a difference when represented in sports performance, HR did provide sufficient evidence and that there was a distribution of differences. Between the two drinks the
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Isotonic Sports Drinks
HR for the commercially branded Lucozade, was in fact higher suggesting that the subjects were working their cardiovascular system harder on that test to be able to maintain a steady pace. Though the reason for maybe the first drink (Lucozade) having a higher HR may have also been down to the fact that the subjects may of be suffering from anxiousness and nerves as it was the first drink to be tested (9). RPE has similar results to figures 1 and 2 as there was yet again no significant difference between the data samples due to the lack of data to compare through the paired t-Test. Though this was the result for RPE it does have correlations to HR and if the RPE was calculated differently using a VO2 max test it may have shown a different result as some of the subjects may have under predicted how they felt at set points of the testing. A study by Khanna and Manna (3) showed their RPE through a VO2 max test instead of using the BORG scale which gave them an accurate reading which corresponded well with their subjectâ&#x20AC;&#x2122;s HRâ&#x20AC;&#x2122;s. From reviewing the results of figures 5 and 6 it concludes that the RPE in the terms of the BORG scale should be used as a guidance relating to other data collections, rather than an independent set of measuring in relation to this study. HR was the only testing measurement that gave a distribution of differences and a significant difference to the testing proving that the null hypotheses could neither be rejected nor accepted due to only one measurement of the data collection, showing any difference. If the study was to be repeated again prior to the collection of data a statistical test would be chosen as an indication to the sample size needed so that when putting the data through statistical analysis there would be enough evidence to indicate a distribution in differences at a significance level of 0.05.
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Isotonic Sports Drinks
PRACTICAL APPLICATIONS The conclusion from this study proves that both of the drinks are of a similar performance level and that neither one has been shown to be better than the other, which proves that either drink could be used during aerobic exercise. The positives from using the homemade product is that ingredients can be monitored and measured to tailor fit the individual which is also easily accessible and affordable.
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Isotonic Sports Drinks
REFERENCES 1. Bachle L, Eckerson J, Albertson L, Ebersole K, Goodwin J, Petzel D. The Effect of Fluid
Replacement
on
Endurance
Performance.
Journal of
Strength
and
Conditioning Association. 15 (2), p217-224. 2001. 2. Coombes, J. S. Sports Drinks on Dental. American Journal of Dentistry. (18), p101-104. 2005. 3. Khanna G.L and Manna I. Supplementary effect of carbohydrate-electrolyte drink on sports performance, lactate removal & cardiovascular response of athletes. . Human Performance Laboratory, Sports Authority of India, New Delhi, India. 121 (5) p665-669. 2005. 4. Maughan R.J. The Sports Drink as a Functional Food: Formulations for Successful Performance. Proceedings of the Nutrition Society. (57), p15-23. 1998. 5. Maughan R.J and Murray, R. Sports Drinks, Basic Science and Practical Aspects.USA: CRC Press. P1-24. 2001. 6. Mettler S, Rusch C, Colombani P.C. Osmolality and pH of Sport and other Drinks Available in Switzerland. Department of Agricultural and Food Sciences. . 3 (54), p92-95. 2006. 7. Ostojic S. M, Mazic, S. Effects of a carbohydrate-Electrolyte Drink on Specific Soccer Tests and Performance. Journal of Sports Science and Medicine. (1), p4749. 2002. 8. Sawka et al. Exercise and Fluid Replacement. Medicine and Science in Sports and Exercise. 39 (2), P377-390. 2007.
Isotonic Sports Drinks
9.
Sellers. C. Building Self-Confidence. Leeds. The National Coaching
Foundation. P13.1997. 10.
Shirreffs, S M. The Optimal Sports Drink. School of Sport & Exercise
Sciences. 1 (51), p25-29. 2003.
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Isotonic Sports Drinks
ACKNOWLEDGEMENTS For the completion of this study many thanks go to the subjects; Ryan Higgs, Edward Higgs, George Underwood, Sean Clifford and James Slater for the involvement of all three separate tests. For the testing to be able to take place thanks also goes to Severn Vale Gym for being accommodating to the protocol and allowing free use of the rowing machines. Acknowledgement to those at the Falmouth Harbor Commissioners for any support and help needed with the study.
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Isotonic Sports Drinks
FIGURE LEGENDS 1) Figure 1– Mean time of Lucozade and Homemade 2) Figure 23) Figure 3- Mean HR of Lucozade and Homemade 4) Figure 45) Figure 5- Mean RPE of Lucozade and Homemade 6) Figure 67) Figure 7 – Mean time for Lucozade and Water 8) Figure 8 9) Figure 9 – Mean time of Homemade and Water 10) Figure 10 11) Figure 11- Mean HR of Lucozade and Water 12) Figure 12 13) Figure 13 – Mean HR of Homemade and Water 14) Figure 1415) Figure 15- Mean RPE of Lucozade and water 16) Figure 16 17) Figure 17- Mean RPE of Homemade and Water 18) Figure 18
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