The purpose of this study was to investigate the acute effects of carbohydrate restriction (CR) on squat performance and serum energy substrate levels in recreationally trained individuals. It was hypothesized that acute CR would decrease fasting blood glucose levels and further inhibit optimal performance in resistance exercise (RE) due to the high carbohydrate (CHO) demand of RE. Seven healthy, recreationally trained males completed one carbohydrate depletion exercise trial (CDEX) and two resistance exercise trial conditions: A control (CON) resistance exercise (RE) trial and a carbohydrate restricted (CR) RE trial. Resistance exercise performance was measured via total power output of a squat exercise using a novel machine titled the nHANCE Squat Ultimate. The carbohydrate depletion exercise trial (CDEX) consisted of 60 minutes of cycling at >75% of participants heart rate (HR) maximum followed by four 1- minute bouts at >95% HR maximum and two days of reduced CHO intake (<5% daily caloric intake). Fasting blood glucose and triglyceride (TG) levels were measured pre-exercise in both RE trials as well as throughout the CDEX. Total caloric intake (p = 0.00) and total CHO intake (p = 0.00) were significantly lower in the CR (mean + SD: 1661.24 + 691.6 cal, 28.82 + 15.6 g/CHO) compared to the CON (2433.85 + 527.4 cal, 222.41 + 39.8 g/CHO). No differences were found in total grams of protein (PRO) or fat intake between conditions. Percent total daily caloric intake from CHO (p = 0.00) was significantly lower in the CR condition (7.40 + 3.32% CHO), while total daily caloric intake from PRO and fat were significantly higher in the CR (32.90 + 8.54% PRO, 58.17 + 11.96% fat) to the CON (37.81 + 9.26% CHO, 20.03 + 5.53% PRO, 37.47 + 11.80% fat). Fasting blood glucose levels (p = 0.017) were significantly lower in the CR (84.57 + 4.79 mg/dL) compared to the CON (93.28 + 6.90 mg/dL) yet there was no difference in blood TG levels (p = 0.177; 64.43 + 15.13 mg/dL vs. 59.29 + 14.16 mg/dL). Total average power output (p = 0.05) and total peak power output (p = 0.047) were significantly lower in the CR. Negligible correlations were found between fasted energy substrate levels and RE performance. Ultimately, a CDEX trial combined with 48 hours of CR and caloric restriction acutely lowers fasting blood glucose levels in recreationally trained males yet has detrimental effects on RE performance during the initial phase of CR.
|Commitee:||Cotter, Josh, Escobar, Kurt|
|School:||California State University, Long Beach|
|School Location:||United States -- California|
|Source:||MAI 81/1(E), Masters Abstracts International|
|Subjects:||Kinesiology, Nutrition, Physiology|
|Keywords:||Anaerobic, Carbohydrate restriction, Glucose, Low carbohydrate, Resistance exercise, Resistance training|
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