Effectiveness of Sports Nutrition Education Based on Self-Determination Theory for Male University Rowing Athletes: A Randomized Controlled Trial.

To resolve problems in the dietary life of university athletes, education is essential to enable athletes to change their own dietary behavior. The purpose of this research was to verify the effectiveness of sports nutrition education based on self-determination theory (SDT). The participants were 36 male university rowers. A stratified randomized comparison test was conducted by student year (SDT group and control group). Sports nutrition education was held three times, via an Internet conferencing system. Furthermore, group work over social media was used for the SDT group. Four evaluations were carried out based on anthropometric measurements, a brief self-administered diet history questionnaire (BDHQ), sports nutrition knowledge test (SNK), and treatment self-regulation questionnaire (TSRQ). The results showed no differences between the two groups. However, for the intragroup factor, "Protein", a significant difference was evident in the self-determination theory group (50.0 ± 28.5, 78.6 ± 28.1, 81.0 ± 21.5, p < 0.000, units: %) and improved knowledge (p = 0.002, p = 0.002). And for the BDHQ, the self-determination theory group also showed significant differences and increased their intake of green and yellow vegetables, fruits, and dairy products (159.1 ± 74.2-126.7 ± 70.6, p = 0.009, 306.0 ± 196.2-195.2 ± 146.1, p = 0.020, 257.0 ± 147.0-183.3 ± 167.9, p = 0.040, units: g). In conclusion, sports nutrition education based on SDT improved dietary knowledge and increased food requirements for athletes.

Possible Association of Energy Availability with Transferrin Saturation and Serum Iron during Summer Camp in Male Collegiate Rugby Players.

Low energy availability (LEA) may persist in rugby players. However, timely assessment of energy balance is important but is difficult. Therefore, a practical index that reflects energy availability (EA) is essential. A total of 19 male college rugby players participated in a 2-week pre-season summer camp. Their blood sample was collected after overnight fast prior to (Pre), in the middle (Middle), and after (Post) the camp. Their physical activity in the first half of the camp was calculated using the additive factor method in the forwards (FW; numbers 1-8) and backs (BK; numbers 9-15). The participants were categorized as tight five (T5; numbers 1-5), back row (BR; numbers 6-8), and BK for analysis. All the participants lost weight during the camp (range: from -5.9% to -0.1%). Energy balance in the first half of the camp was negative. Transferrin saturation (TSAT) and serum iron levels significantly decreased to half, or even less, compared with the Pre levels at week 1 and remained low. The changes in TSAT and serum iron levels exhibited a significant positive correlation with the changes in body weight (R = 0.720; R = 0.627) and with energy intake (R = 0.410; R = 461) in T5. LEA occurs in rugby summer camp but is difficult to assess using weight change. Alternately, TSAT and serum iron levels after overnight fast may be better predictors of LEA.