Gender-related Difference of Body Composition, Aerobic, Anaerobic Capacity and Isokinetic Muscle Strength in Collegiate Taekwondo Athletes

BACKGROUND: This study aimed to investigate the relationships among ACTN-3, body composition, fitness, and +Gz tolerance for senior cadet training development and their safe task performance.METHODS: The subjects were all senior cadets (N = 68) at the Korea Air Force Academy. All cadets are required to pass a physical fitness test (3-km running, sit-ups, push-ups) and body composition test on a semiannual basis. Isokinetic muscle function (strength and endurance), +Gz test (+6 Gz ⋅ 30 s−1), and target gene (ACTN-3) were analyzed.RESULTS: The effects of body composition and physical fitness along with the relationship of the ACTN-3 genotype to the +6 Gz test results were determined. Consequently, no significant difference was found concerning the effect of ACTN-3 on the +6 Gz test result, body composition, and physical fitness; however, body fat (%) and isokinetic muscle strength (peak torque right leg extension and left leg flexion) showed significance between the pass and failure groups in the +Gz test.DISCUSSION: The cadets of the Korea Air Force Academy showed dominant fast genetic expression type based on their ACTN-3 genotype [RR and RX (N = 51, 75%) > XX (N = 17, 25%)]. Body fat (%) and isokinetic muscle strength (PT R EX, L FL) can be more effective predictors in the +6 Gz test for cadet training. Another speculation is that more RR- and RX-type-oriented training can promote cadets’ Gz tolerance from the isokinetic factors such as high peak torque and low fatigue index.Shin S, Jee H. ACTN-3 genotype, body composition, fitness, and +Gz tolerance in senior cadets. Aerosp Med Hum Perform. 2019; 90(12):1055–1060.

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Betaine Supplementation Does not Improve Muscle Hypertrophy or Strength Following 6 Weeks of Cross-Fit Training

Nutrients ◽

10.3390/nu12061688 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1688 ◽

Cited By ~ 1

Author(s):

Tatiana Moro ◽

Francesca Badiali ◽

Iader Fabbri ◽

Antonio Paoli

Keyword(s):

Body Composition ◽

Muscle Strength ◽

Fat Mass ◽

Anaerobic Capacity ◽

Muscle Performance ◽

Specific Test ◽

Trained Subjects ◽

Back Squat ◽

Before And After ◽

Betaine Supplementation

We aim to investigate the effect of 6 weeks of betaine supplementation on body composition and muscle performance during CrossFit© training. Twenty-nine subjects matched for training status (4.16 ± 0.95 day/week) and body fat mass (12.66 ± 4.08%) were randomly assigned to a betaine (BET; N = 14) or placebo group (PLA; N = 15). Body composition and cellular hydration were estimated with skinfolds measurement and bioelectrical impendence before and after 6 weeks of training. Muscle performance was assessed using three different tests: 3-RM back-squat for muscle strength, 2 km rowing test for aerobic capacity and Bergeron Beep Test for anaerobic capacity. Muscle strength assessed during back squat significantly increased in BET (p = 0.04) but not in the PLA group, however, there were no statistical differences between groups. Although not significant, fat mass was reduced in BET compared to PLA. Overall, body composition and cell hydration measurements did not change in response to training or betaine supplementation. Short-term (6 weeks) betaine supplementation supports muscle strength but was not ergogenic for trained subjects to aerobic and anaerobic performance in the CrossFit©-specific test.

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