Muscular Strength and Aerobic Capacity, a Symbiotic Relationship With Birth Weight and Metabolic Risk of Colombian Scholchildren: Study SIMAC

Type of study: Experimental study with individual analysis. Population object and sample: Adolescents from 12 to 17 years old of high school located in Bucaramanga's metropolitan area. The sample size was calculated to evaluate the difference between the maximum oxygen consumption (VO2max) between the control group and 20% of the intervention groups using an ANCOVA method, with a correlation of 0.5 between the initial and final evaluations. An error alpha of 0.05 and power of 0.8, obtaining a sample of 60 adolescents for each group.

Description of the physical intervention or program: This is a strength, power and endurance training program of moderate intensity combined with aerobic capacity training Moderate in the form of circuit. The trainings will be performed twice a week between 30-60 minutes of training, 1 hour including heating, stretching, explanations and cooling.

Baseline assessment: All adolescents will be provided with a CRF for past medical history and family history, a review of systems and physical examination. In addition, the following evaluation protocol is established: Health related physical fitness measurement (AFRS): Aerobic capacity, maximal strength, 6RM submaximal strength test, strength, power, muscular endurance and flexibility; Anthropometric measurements and body composition; Complete Blood Count (CBC), and Lipid Profile. Measurements with AFRS will be taken at baseline, after 3 months of the program and at the end (6 months).

Aerobic capacity: To measure the aerobic capacity, 20 Meter Shuttle Run Test will be applied. A site would be selected for the test, preferably a space of 25 meter or longer. It would need 4 cones, tape measure, compact disc (CD) with the test protocol and a CD player. The two ends of the 20-meter track should be clearly marked. For the execution, the adolescent will move from one line to another located 20 meters away and making the change of direction to the rhythm that is indicated by a sound signal that will progressively accelerate. The initial velocity of the signal would be 8.5 km/hr, and will increase by 0.5 km/hr/min (1 minute is equal to one shuttle). The test will end when the adolescent is not able to arrive for the second time in a row to the start line with the audio signal. Otherwise, the test will end when the teen stops because of fatigue. The participant would start running when the CD player emits the sound. The participant will touch the line at the end of the track with the feet, turn abruptly and run in the opposite direction. At first the speed will be low, but it will increase slowly and steadily every minute. The participant will stop when they no longer can keep the pace set. Or if they feel unable to complete the one-minute period. It is important to remember the last number announced by the CD player when the participant stops, because this will be the participant's score. This test would be performed only once. When the schoolchildren finish the test or cannot keep the pace, the last completed palier would be recorded.

Maximum isometric force: Hand dynamometry is an important test for assessing the physical performance and nutritional status of the participants and allows reference to the isometric muscular strength of the hand. The improve in muscle strengths are inversely associated with changes in total adiposity in childhood and adolescence. This test requires an adjustable dynamometer (TKK 5101 Grip D; Takey, Tokyo Japan) and a Right- and left-Hand Grip Rule. The Adolescent will tighten the dynamometer gradually and continuously for less than 2 seconds, performing the test twice (alternately with both hands) with the optimal grip adjustment according to the size of the hand (previously calculated with the hand grip rule). Allowing a short break between measurements for each measurement. The elbow should be in all its extension and the participant has to avoid the contact of the dynamometer with any part of the body. The Adolescent will take the dynamometer with one hand, try to apply the mayor strength possible. Would Squeeze gradually and continuously for less than 2 or 3 seconds. The examiner will show the correct form of execution. Adjust the grip measure according the size of the hand. The test will be done twice and the best result will be recorded. The maximum duration of the test will be 3-5 seconds, the size of the hand (right or left) should be measured to the maximum width. The accuracy of the measurement is 0.5 cm. During the test, the arm and hand holding the dynamometer do not touch the body. The instrument is held in line with the forearm. After a short break, a second attempt will be made.