The Effect of Eight Weeks of High-Intensity Interval Training on Physical Performance in Young Taekwondo Athletes

Primary outcomes

1. Taekwondo-Specific Agility Test (TSAT)

   Time frame: For 8 weeks from the start of the study

   As previously described, the test begins with the athlete in a guard position, with both feet positioned behind the starting/finishing line, and proceeds sequentially as follows:

   • The athlete must move as quickly as possible into the center point while maintaining the guard position.
   • The athlete must change direction, turn toward Partner 1, and perform a Palding kick with the left leg.
   • The athlete must move toward Partner 2 and perform a Dollyo-Chagi kick with the right leg.
   • The athlete must return to the center.
   • The athlete must move forward in the guard position, and perform a Double Palding kick toward Partner 3.
   • Finally, the athlete must return to the starting/finishing line while maintaining the guard position.

2. Frequency Speed of Kick Test (FSKT10s)

   Time frame: For 8 weeks from the start of the study

   To assess the best possible single FSKT score, athletes were subjected to the FSKT10s. In this test, athletes were instructed to perform as many mid-level kicks as possible within a 10-second period, with the total number of valid kicks recorded as the score. Following a five-minute rest, the protocol was repeated, and the best score from the two trials was recorded as the FSKT10s . According to the FSKT classification, athletes who performed 16 or fewer kicks were classified as "very poor," those with 17 kicks were categorized as "poor," 18-21 kicks as "average," 22-23 kicks as "good," and 24 or more kicks were classified as "excellent".

3. Multiple Frequency Speed of Kick Test (FSKTmult)

   Time frame: For 8 weeks from the start of the study

   To assess the athletes' FSKTmult scores, the FSKT test was conducted in five consecutive sets, with 10-second rest intervals between each set. Each set consisted of the maximum number of kicks the athletes could perform within 10 seconds, as previously described. At the end of the five sets, the total valid kicks performed by the athletes in each set (FSKT1, FSKT2, FSKT3, FSKT4, FSKT5) and the overall total (FSKT5x10s total) were recorded for analysis.

4. Kick Decrement Index (KDI)

   Time frame: For 8 weeks from the start of the study

   To indicate performance decrement in the FSKT5x10s test, the KDI (%) ratio was used. This ratio incorporates the number of kicks performed in each set and the potential maximum number of kicks, calculated using the equation provided below.

   KDI (%) = [1-(FSKT_1+FSKT_2+FSKT_3+FSKT_4+FSKT_5)/(Best FSKT x Number of Sets)] x 100

5. Vertical Jump Test

   Time frame: For 8 weeks from the start of the study

   The TKK 5406 jump meter was used to apply the vertical jump test. Prior to the test, athletes were allowed sufficient repetitions to familiarize themselves with the equipment. During the test, athletes were instructed to stand with both feet on the mat of the measurement device and jump as high as possible when the device's light signal was activated. Arm and leg swings were permitted during the jump. Care was taken to ensure that athletes landed on both feet simultaneously. The vertical jump distance for each athlete was recorded from the device's display after the jump. The test was repeated three times, with a 1-minute rest interval between attempts. The best jump from the three trials was recorded as the athlete's vertical jump performance.

6. Standing Long Jump Test

   Time frame: For 8 weeks from the start of the study

   Athletes were positioned with their toes just behind the starting line, feet at a normal width, and with their arms extended forward and knees bent in a pre-jump stance. They were instructed to jump as far as possible, using their arms for momentum, and both feet were to land simultaneously. The distance from the starting line to the athlete's heels was measured in centimeters and recorded. Athletes were given two attempts, and the best result was taken for analysis.