2015 Undergraduate Research
Janae L. Myers, Isabel E. Sim-Campos, Maren E. Iverson
Exercise Science and Sport Study
Poster presented at the American College of Sports Medicine National Conference in San Diego, CA, May 2015
The Dynamic Postural Stability Index (DPSI) is a reliable measure of dynamic postural stability when the jump-landing task constrains the trajectory of the body prior to landing, such as by jumping over a hurdle or jumping to touch an overhead goal. Purpose: To examine test-retest reliability of the DPSI when body trajectory prior to landing is not constrained by a hurdle or overhead goal. Methods: Forty-eight healthy, physically active participants [24 males (20.6 ± 1.2 years of age, 86.1 ± 11.6kg, and 179.6 ± 8.3cm) and 24 females (19.75 ± 0.8 years of age, 62.8 ± 8.3kg, and 166.3 ± 6.8cm)] performed an anterior leap and a lateral leap from the left (non-dominant) leg, landed on the right (dominant) leg at a distance equivalent to 50% of their maximal leap distance, stabilized their body over the base of support as quickly as possible, and balanced for three seconds. Ground reaction forces in the x, y, and z directions, sampled at 200 Hz, were used to calculate the DPSI. One trial of each leap-landing direction was performed during three test sessions separated by at least 20 hours, but not more than 48 hours. Data from three test sessions were analyzed using an intraclass correlation coefficient (ICC 3,1) formula. Results: Test-retest reliability of the DPSI was judged to be questionable when landing from a forward leap (ICC = .711; 95% CI = .583 - .814) and lateral leap (ICC = .640; 95% CI = .493 - .763). Conclusion: The test-retest reliability of the DPSI when body trajectory prior to landing is not constrained by a hurdle or overhead goal is questionable. Therefore, it is recommended that DPSI testing continue to utilize jump-landing protocols that involve a jump over a hurdle or jump to touch an overhead goal as the test-retest reliability of the DPSI utilizing such protocols has been shown to be moderate to high.
Sarah A. Roehl, Charles G. Broback, Samuel J. Scoblic
Exercise Science and Sport Study, NATS
Poster presented at the 2015 Scholarship and Creativity Day at the College of Saint Benedict, St. Joseph, MN
Research studies utilizing the Dynamic Postural Stability Index (DPSI), a commonly used method to assess an individual's ability to transition efficiently from a dynamic to static state, typically analyze dominant leg (DL) and non-dominant leg (NDL) DPSI values separately. Purpose: To compare DL and NDL DPSI values to determine if there are significant differences in mean scores, which could justify the practice of examining DL and NDL values separately. Methods: Thirty-two healthy and physically active subjects [16 males (19.8 ±1.3 years, 85.6 ±13.0 kg, 180.3 ±8.9 cm) and 16 females (20.2 ±1.0 years, 64.8 ±20.4 kg, 165.2 ±11.2 cm)] completed 20 jumps, landing on one leg on a force plate. Ten jumps were performed in the anterior direction (5 landing on the DL and 5 on the NDL) over a 30 cm hurdle at a distance equal to 40% of body height. Ten jumps were also performed in the lateral direction (5 landing on the DL and 5 on the NDL) over a 15 cm hurdle at a distance equal to 33% of body height. Ground reaction forces in the x, y, and z directions, sampled at 200 Hz, were used to calculate DPSI values in each of the four conditions. Data was analyzed using dependent t-tests. Results: Dependent t-tests revealed no significant differences between mean DPSI values for the DL (0.350 ±0.06; 0.314 ±0.06) compared to the NDL (0.353 ±0.05; 0.312 ±0.05) when landing from an anterior and lateral jump respectively (t(31) = -0.429, p = .671; t(31) = 0.148, p = .883). Additionally, the effect size differences between the DL and NDL were found to be small when landing from the anterior (d = 0.05) and lateral jump (d = 0.03). Conclusion: The non-significant differences in the means and the small effect sizes indicate the DPSI values associated with DL and NDL when landing from an anterior and lateral jump are similar. Therefore, the determination of leg dominance may not be necessary when evaluating dynamic postural stability using the DPSI.
Melissa A Seldon, Benjamin F Hodapp
Exercise Science and Sport Study, NATS, Physics
Poster presented at the 2015 Scholarship and Creativity Day at the College of Saint Benedict, St. Joseph, MN
Since the ground is the only external contact for a softball pitcher, ground reaction force (GRF) is theorized to be an important factor in determining softball pitch velocity, yet little research examining this relationship has been published. Purpose: To examine the relationship between the GRF of the stride leg and softball pitch velocity. Methods: Three right hand dominant female Division III intercollegiate softball pitchers (18.3 ±0.6 years; 72.1 ±1.6 kg; 168.0 ±7.9 cm) performed 15 maximal velocity fastball pitches into a net, landing on a force plate with their stride leg, during two separate test sessions (total of 30 pitches per pitcher). Ball velocity was measured to the tenth of one mile per hour using a Stryker radar gun and converted to meters per second. Peak vertical and braking GRFs, sampled at 600 Hz, were normalized to body weight (BW). The slope of the vertical and braking GRFs were calculated by dividing peak GRF by the time from ground contact, defined as the first upward deflection in GRF greater than 5% body weight, to peak force. A Pearson correlation was used to examine the relationship between GRF variables and ball velocity for all 90 pitches. Results: A significant positive correlation was found between ball velocity (23.5 ±0.9 m/sec) and vertical GRF (1.680 ±0.486% BW; r(90) = .696, p < .001), breaking GRF (1.096 ±0.231% BW; r(90) = .854, p < .001), slope of the vertical GRF (31066 ±15952 N/s; r(90) = .294 p = .005), and slope of the braking GRF (12296 ±5457 N/s; r(90) = .535, p < .001) of the stride leg. Conclusion: When a softball is pitched for maximal velocity by Division III softball pitchers using their normal mechanics, there is a positive relationship between GRF variables and ball velocity. Further research is needed to determine whether altering pitching mechanics to accentuate GRF variables will result in greater pitch velocity.
Morgan N Potter
Exercise Science and Sport Study, Nutrition
Poster presented at the 2015 Scholarship and Creativity Day at the College of Saint Benedict, St. Joseph, MN
Purpose: Research on the relationship between dairy consumption and BMI and percent body fat has been inconsistent. Additionally, there is minimal research on the relationship in American adult populations. Methods: 169 males and 344 females in a small college community were surveyed about their beverage consumption and exercise habits. Participants were 34 +15.6 years old with 45% of the participants between the ages of 18 and 22. On average, the participants consumed 10.6 ±12.6 oz of milk (low fat, reduced fat, and whole milk) per day, with 79.1% of participants drinking only low fat milk. Results: A Pearson correlation revealed an inverse relationship between the consumption of milk and BMI (r= -.104, p=0.019), and a positive relationship between consumption of milk and minutes of exercise per week (r= .179, p<.001). Females also had an inverse relationship between milk consumption and BMI (r= -.150, p= .005). Males had a stronger positive correlation between milk and minutes of exercise per week (r=.219, p=.004) than females (r=.152, p=.005). A sub sample of the participants (40 males, 58 females, 28 +12.3 years, 14.1 +16.5 oz milk per day) volunteered for body composition testing with bioelectrical impedance. In this smaller sample, body fat was significantly and inversely related to milk consumption (r=.-.313, p=.002). Milk consumption was also significantly positively related to physical activity (r=.307, p= .002). Conclusion: Regular exercise and some properties of milk, such as calcium, may play a role in regulation of fat metabolism. Further, individuals who partake in one healthy behavior are more likely to partake in multiple healthy behaviors, such as exercise and healthy eating which can help maintain healthy body consumption.
Megan E Lawson
Exercise Science and Sport Study
Introduction: Dynamic postural stability is the ability to maintain stability when transitioning from a dynamic to static state. Dynamic postural stability can be measured using the Dynamic Postural Stability Index (DPSI), which is calculated using its directional components Anterior-Posterior Stability Index (APSI), Medial-Lateral Stability Index (MLSI), and Vertical Stability Index (VSI). With evidence that ankle bracing can enhance ankle proprioception, ankle bracing may enhance performance during DPSI testing because dynamic balance relies on proprioception and somatosensory feedback. Purpose: Because prophylactic ankle bracing is common in sport and exercise, it is important to understand how it may impact dynamic postural stability. The purpose of this study is to determine if prophylactic ankle braces have an effect on DPSI values. Methods: Seven males (20.14 ± 0.89 years, 81.44 ± 13.92 kg, 180.96 ± 4.58 cm) and 24 females (20.54 ± 0.72 years, 64.39 ± 8.79 kg, 164.74 ± 6.57 cm) who were physically active and had not worn an ankle brace in the last five years completed the DPSI test protocol. The protocol consisted of three jumps, each landing with the dominant foot on an Accupower force platform. Subjects jumped a distance that was 40% of their height, and over a 12 inch hurdle. One trial was completed without an ankle brace on and another was completed with a brace on the ankle of the dominant leg. Average DPSI, APSI, MLSI, and VSI values for each trial were used for data analysis. Results: A paired samples t-test was used for data analysis. No significant difference between braced (0.086 ± 0.011) and non-braced (0.087 ± 0.015) conditions was found for average APSI values [t(30) = -0.46, p > .05]. No significant difference between braced (0.036 ± 0.014) and non-braced (0.036 ± 0.013) conditions was found for average MLSI values [t(30) = 0.00, p > .05]. No significant difference between braced (0.310 ± 0.0395) and non-braced (0.030 ± 0.043) conditions was found for average VSI values [t(30) = 1.33, p > .05]. A nonsignificant difference between braced (0.325 ± 0.039) and non-braced (0.319 ± 0.044) conditions was found for average DPSI values [t(30) = 1.25, p > .05]. Conclusion: Wearing an ankle brace has no effect on the performance of the DPSI. Ankle braces will neither enhance nor inhibit dynamic postural stability.
Exercise Science and Sport Study
Static and dynamic stretching are often used to help prepare for sport or activity. However, research examining the effect that different stretching protocols have on agility and vertical jump performance remains inconclusive. The purpose of this study was to examine the effect of static and dynamic stretching protocols on countermovement jump (CMJ) and Illinois Agility Test (IAT) times. 9 recreationally active males between ages 18-22 (178.76 SD=2.74 cm, 75.74 SD=16.32 kg, 9.62% SD=4.81% body fat) completed this study. Participants began each session with a 400m jog, then performed one of three stretching protocols. The stretching protocol for each session was chosen in a randomized order. Following the completion of the stretching protocol, subjects completed three CMJs, then completed the IAT 3 times. The best of the three trials for CMJ and IAT was used for data analysis. Mean IAT times were 16.72s (SD=1.28), 16.53s (SD=.95), and 16.43s (SD=.88) for the control, static, and dynamic stretching protocols respectively. CMJ heights were 65.12cm (SD=16.32), 64.56cm (SD=7.74), and 65.02cm (SD=8.71) for the control, static, and dynamic stretching protocols respectively. A one way repeated measures ANOVA was used to test the data for significance. No significant differences were found within subjects for IAT (F (2,16) = 2.31, p = .13) or CMJ (F (2,16) = .14, p = .875). The lack of difference between treatments may have been due to too much time immediately following protocols, therefore negating any benefit that would result from the stretching protocol. While no significant differences were found between IAT and CMJ performance with different stretching protocols, this does not necessarily mean stretching protocols are equally advantageous for jump and agility performance. Further research is needed to understand the benefits of different stretching protocols on agility and vertical jump performance. Research examining power and agility performance immediately following stretching protocols, or stretching protocols with stretches held for longer durations may yield different results.
Margaret M Paul
Communication, Exercise Science and Sport Study, Gender & Women's Studies
Weight bearing activity is an important component of overall health. According to the CDC (2007), only one third of women aged 18-24 obtain sufficient levels of physical activity, making them a particular concern. Many women may lack knowledge of proper weightlifting techniques, have incorrect information about weightlifting or have time constraints that prevent them from participating. PURPOSE: To determine if and why college aged women participate in or withhold from weight training methods. METHODS: 249 college-aged women were surveyed and 12 of those women participated in small focus groups. RESULTS: 57.8% of women were in the "normal" BMI category. Survey participants indicated that they were mostly "healthy" or "very healthy" (82.4%). Despite being an active sample, (88% indicated that they were either "active" or "very active"), less than half of respondents indicated that they participated in weightlifting either "often" or "very often". Additionally, 27.7% of women agreed, strongly agreed or were neutral when answering the statement, weightlifting is unnecessary when I am being physically active. Women reported the top three factors that motivated them to participate in weightlifting were to stay in shape, it made them feel good and it improved how they looked/the way they felt about their body. For women who faced obstacles when trying to include weightlifting into their workouts, time constraints seemed to be the largest barrier. It is possible that women place a great deal of emphasis on aerobic exercise and thus, lack time to add weightlifting to their exercise routine. CONCLUSION: Though the reported activity levels in this sample were encouraging, an effort should still be made to address misconceptions and a lack of education surrounding weightlifting, especially in college aged women. More health and fitness education may help college students shift their attitudes and feel more empowered about adding weightlifting to their exercise routines. Campus-wide campaigns with high visibility tactics that deliver more than one component, such as educating and programming, have the potential for causing positive behavior change. Efforts such as these could be useful strategies in increasing the levels of participation of women in weightlifting on college campuses.
Poster presented at MAND [Minnesota Academy of Nutrition and Dietetics], April 30th, Minneapolis, MN
Sleep deprivation is one of the top five threats to academic achievement. Unfortunately, college students often lack adequate quantity and quality of sleep. Many students use caffeinated beverages as a stimulant source in an attempt to make up for their lack of sleep.PURPOSE: to determine whether caffeine can compensate for a lack of sleep regarding mood and memory in students getting either ≤ 6 or ≥ 8 hours of sleep per night.METHODS: Institutional Review Board approval was obtained. A sleep questionnaire, linked to a recruitment email, was sent to sophomore, junior, and senior females at the college (n=57). Habitual sleep patterns were used to assign participants to one of two groups, ≤ 6 hours (N=12) or ≥ 8 hours (N=15). Exclusion criteria were smoking, medications (excluding birth control), and caffeine sensitivity. Subjects read and signed an informed consent before participating in the study. Subjects consumed a flavored beverage in two trials, once with caffeine (200 mg) and once without, in a double-blind crossover design. Working memory was assessed by a word recall task. Mood was assessed by a self-reported mood questionnaire, which contained six positive and six negative symptoms. A 2 X 2 mixed ANOVA through SPSS was used to analyze the data. Correlation coefficients were used to analyze sleep patterns and GPA.RESULTS: The mean number of words recalled increased by 3% with caffeine treatment in the group sleeping ≤ 6 hours and by 8% in the group sleeping ≥ 8 hours (p=0.081). Positive mood scores increased by 2.3% with caffeine treatment in the group sleeping ≤ 6 hours and by 17.7% in the group sleeping ≥ 8 hours (p=0.011), with a statistically significant interaction between the sleep group and treatment (p=0.042). Negative mood scores decreased by 10.3% with caffeine treatment in the group sleeping ≤ 6 hours and by 2.9% in the group sleeping ≥ 8 hours (p=0.03).CONCLUSION: Caffeine improved mood and memory in both groups, but was less effective in the group lacking adequate sleep. Therefore, caffeine cannot completely compensate for a lack of sleep as maximal improvement was achieved by the group obtaining ≥ 8 hours of sleep per night.
James T. Ford
Poster presented at the NACSM meeting [Northland Chapter of the American College of Sports Medicine, April 10th, St. Cloud, MN
Pre-workout products are some of the most aggressively marketed supplements and typically contain caffeine, creatine and other proposed ergogenic ingredients. Research supporting these products and whether a combination of ingredients enhances anaerobic performance any better than caffeine alone is limited. Purpose: 1) To determine if a single dose of a National Science Foundation (NSF) safe pre-workout supplement is more effective than caffeine alone at enhancing anaerobic performance, and 2) To determine the knowledge and use of nutritional supplements by DIII football players.Methods: IRB approval and informed consents were obtained for this double-blind, crossover study. Players (n=12) were recruited to participate in the pre-workout supplement study comparing a placebo, caffeine only and pre-workout supplement (Extreme Edge Pre-workout formula). Subjects completed three anaerobic tests including: maximum repetition bench press test at 50% of max weight, a vertical jump test, and three electronically timed 40 yard sprints. A one-way analysis of variance (ANOVA) was used to determine significance of mean bench press reps, vertical jump heights and sprint times. An anonymous survey was administered electronically to a DIII football team to assess basic knowledge and use of nutritional supplements (n=96).Results: The pre-workout supplement did not statistically improve anaerobic performance in maximum bench reps [M= 18.3 reps, SD= 4.62, p = 0.941], average vertical jump height [M=26.36 inch, SD= 3.32, p = 0.973] or average sprint time [M=5.37 sec, SD= .488, p = 0.991]. Many football players (54.3%) report using nutritional supplements; 82.8% of the supplements were protein powder, 51.3% creatine, and 42.3% were pre-workout supplements. Despite widespread use, 34% of players did not know the role of creatine and 67% did not know the function of caffeine in the body.Conclusion: Many players use nutritional supplements; however, a single dose of the Extreme Edge Pre-workout Formula was not more effective than caffeine alone or placebo in enhancing anaerobic performance. Although single use of this pre-workout supplement did not improve performance, the effects of long term use were not determined. Based on the results of this study, the benefits of this product do not appear to be worth the high cost.
Poster presented at MAND [Minnesota Academy of Nutrition and Dietetics, April 30th, Minneapolis, MN.
Fluoride is added to community water sources to prevent dental caries. However, excessive fluoride intake may contribute to dental and/or skeletal fluorosis. The incidence in fluorosis is increasing due to fluoride sources in the diet and the addition of fluoride into water supplies. The optimal intake of fluoride is between 0.05 and 0.07 mg per kg body weight per day. 1 Tea (Camellia sinensis), one of the worlds most consumed beverages, can contain high levels of fluoride but it is recommended due to its many health benefits. Purpose: To determine the concentration of fluoride in popular teas and the amount of tea consumed by the college-aged population. Methods: An anonymous survey was distributed electronically through email after Institutional Review Board approval (n=1815). Participants (98 females and 30 males) completed a survey assessing beverage consumption. Informed consent was the first page of the survey; consent was implied by completing the survey. Survey results directed the selection of teas to analyze. Five types of tea from five brands were purchased from local grocery stores. Each tea was brewed in 240 ml of boiling water for 3 minutes in triplicate. Teas were analyzed for fluoride concentration using a fluoride ion-selective electrode. Two-way ANOVA was used to examine the effect of tea type and flavor on fluoride concentration. Results: The mean fluoride concentration for green tea was 7.0 mg/L (SD = 2.6), black tea 4.8 mg/L (SD = 3.0), citrus tea 0.3 mg/L (SD = 0.2), fruity tea 0.3 mg/L (SD = 0.1), and floral tea 0.3 mg/L (SD = 0.1). Two-way ANOVA yielded a statistically significant interaction between the effects of tea type and flavor on fluoride concentration [F (16, 50) = 27.025, p = .000]. The fluoride concentrations were statistically different among black tea brands [F (4) = 100.768, p = .000], green tea brands [F (4) = 16.100, p = .000], and citrus tea brands [F (4) = 8.269, p = .003]. Fluoride concentrations were very low and did not differ among fruity [F (4) = 1.540, p = .264] and floral tea brands [F (4) = 4.028, p = .034]. Seventy-five percent of the college-aged population consumed 6 or less tea beverages per week, while two percent consumed 21 or more tea beverage. The most commonly consumed types of tea consumed are green (70.4%), black (59.2%), floral (46.4%), fruity (45.6%), and citrus (38.4%) (participants indicated all types of tea that they consume). Conclusion: The fluoride concentration of tea type varies with brand with black and green teas containing the most fluoride and citrus, fruity, and floral teas containing very low fluoride. Three or more green or black tea beverages per day provides 5.11-7.45 mg/L, which exceeds 0.05-0.07 mg fluoride concentration per kg per day, the optimal intake of fluoride (assuming a 68 kg college-aged student and 12-ounce beverage). Three participants consume more than the optimal intake of fluoride from tea alone. The majority of the college-aged population is not at risk for excess fluoride intake based on tea consumption alone; however, fluoride concentrations should be listed on nutritional labels so that consumers can make informed decisions regarding their health. 1 Warren, J., Levy, S., Broffitt, B., Cavanaugh, J., Kanellis, M., & Weber-Gasparoni, K. (2009). Considerations on optimal fluorite intake using dental fluorosis and dental caries outcomes- A longitudinal study. Journal of Public Health Dentistry, 69(2), 111-115. doi: 10.1111/j.1752-7325.2008.00108.x.
Poster presented at MAND - Minnesota Academy of Nutrition and Dietetics, April 30, Minneapolis, MN
Addiction to highly refined foods, specifically sugar, may result in excessive caloric intake, which enhances comorbidity risks, such as obesity and cardiovascular disease. The American Heart Association recommends that women limit "added sugar" intake to 25 g per day (1). Purpose: To determine the relationship between food addiction and sugar consumption. Methods: IRB approved the study, and IT Services sent out a recruitment email to 1992 college-aged females. Participants gave their informed consent and completed two surveys: the Yale Food Addiction Scale (YFAS) (n=160) and the Automated Self-Administered 24-hour dietary recall (ASA24) (n=57). The YFAS questionnaire categorized individuals into two groups based on the DSM-IV substance abuse criteria: food dependents, or food addicts, and non-food dependents, or non-food addicts. The ASA24 analyzed participants' dietary recalls of all foods/beverages consumed in the last 24 hours. T-tests and ANOVAs compared nutrition intakes of food dependents with non-food dependents. Results: The YFAS categorized the respondents as 31.3% food dependent (n=50) and 68.8% non-food dependent (n=110); 13 food dependents and 44 non-food dependents completed the ASA24. Only 35.6% of participants (n=57) complete both surveys. The range of "added sugar" consumed was 0 - 395 grams. Food addicts consumed 77.5 ± 101.5 g of "added sugar" and non-food addicts consumed 51.5 ± 36.5 g of "added sugar"; however, there was no statistical difference between groups (p=0.158). Food dependents consumed less sodium than non-food dependents, 2308 ± 681 mg and 2980 ± 1051 mg sodium respectively, which was statistically significant (p=0.034). Conclusions - A food addiction diagnosis did not correlate with a higher "added sugar" intake in this study (p>0.05), and food addicts consumed a significantly lower amount of sodium than non-food addicts (p=0.034). A surprising percent of college-aged females were categorized as food addicts (31.3%), which is higher than other reports (8.8%). Most food addicts and non-food addicts (70%) are consuming more than the American Heart Association's recommended amount of "added sugar" (<25 grams per day). ·1. American Heart Association. (2014). Added sugars. American Heart Association. 1-2. http://www.heart.org/HEARTORG/GettingHealthy/NutritionCenter/Sugars-101_UCM_306024_Article.jsp
Poster presented at NACSM [Northland Chapter of the American College of Sports Medicine], April 10th, St. Cloud, MN.
Professional ballet dancers on average weigh 10 to 20% below ideal weight (1). The NCAA does not monitor collegiate dance teams, so body weight and nutritional practices of collegiate dancers is relatively unknown. Purpose: To determine if the collegiate dancers are considered at risk for developing an eating disorder and to assess nutritional misconceptions. Methods: 25 Division III female dance team members participated in the study. Approval from the Institutional Review Board (IRB) was obtained, and subjects completed an informed consent. Subjects were asked to complete an electronic survey that was distributed via email. The electronic survey included questions from the EAT-26 and a nutritional knowledge questionnaire. Subjects were asked to complete an ASA-24 electronic 24-hour recall. Correlations were analyzed using a bivariate correlation and unpaired t-test with Service Product for Statistical Solution (SPSS). Results: EAT-26 scores averaged 4.56 +/- 6.7 indicating a low risk for an eating disorder (n=25). Only one dancer indicated a high risk with an EAT-26 score of 31. There was a strong, though statistically insignificant, correlation between the EAT-26 score and nutritional knowledge (r=-0.307, p=0.068, n=25). Participants (n=25) scored, on average, 66% on the nutritional knowledge questionnaire; however, those who had taken a nutrition course scored significantly higher, 76% (t = 2.3695, p = 0.0266, df = 23). Only 17 dancers completed the ASA-24. Participants consumed 1747 +/- 630 kcals, including 61.5 +/- 26g protein, 70.7 +/- 34 g fat, and 216.7 +/- 71g carbohydrates, in a 24-hour period. Dancers consumed an inadequate amount of calcium (47%), vitamin C (71%), vitamin B6 (47%), iron (94%), and vitamin D (100%) (n = 17). Conclusion: while overall diets appeared to meet most RDA recommendations, intakes varied extremely and 41% failed to obtain at least 50% of the RDA for more than one nutrient. Improving nutritional knowledge and healthy food choices could decrease eating disorder risk in DIII collegiate dancers.(1) Doyle-Lucas, A. F., & Davy, B. M. (2011). Development and evaluation of an education intervention program for pre-professional adolescent ballet dancers: Nutrition for optimal performance. Journal of Dance Medicine & Science, 15(2), 65-75.