Introduction The effects of traditional strength training, explosive types of weight training and plyometrics on maximal jump performance have been extensively examined [3]. Changes in muscular strength, and power, as a result of resistance training can be related to improve the vertical jump [2, 5]. These types of observation indicate that resistance training can have a transfer of training effect that results in a change in specific functional abilities and capacities. Appropriately choosing a training method can make a considerable difference in the outcome of a resistance-training program [1, 2, 4]. The purpose of this investigation was to compare two different training methods and their effect on vertical jumping ability and associated changes in muscle activity. Methods 23 male students of physical education ( Mean age=20 ± 2 years, height=175 ± 5 cm, mass = 71 ± 3 Kg) assigned to 3 groups participated in the study. Subjects were matched and assigned to a group on the basis of their 1RM squat maximal strength. TW group performed traditional weight training with machines (80-100% of 1RM of squat-test), WL group performed weight lifting exercises (80-100% of maximal lifting ability)and C group served as controls (CG). There were 2 testing periods lasting approximately 2 weeks separated by an 8-week training phase. All groups videotaped with two video cameras (Panasonic AGI88, frame, 60 Hz, performing 6 different vertical jumps (1 squat, 2 countermovement and 3 drop jumps from 20, 40, 60 cm), onto a force platform Kistler (Type 9281CA), sampling at 1000Hz. The EMG activity of rectus femoris, biceps femoris and gastrocnimius was recorded using an EMG interface module of the ARIEL system, 1000 Hz. Tests were performed before and after the application of the training program. Performance variables were the following: Maximal jumping height (SJmax, CMJmax, FCMJmax, and DJ20max, DJ40max, DJ60max), mean power (MP), mean work (MW) and contact time (CT) were obtained from the force plate output. The ankle, knee and hip joint angles, and angular velocity (AJA, KJA and HJA AJV, KJV and HJV respectively) were derived from the video data. Average EMG (Aemg) was calculated by full-wave rectification and averaged over the pre-contact, eccentric and concentric phases. Results ANOVA with repeated measures design for kinetic, kinematic and EMG variables was applied and showed statistical significant interaction for SJmax(F2,22=34,3), CMJmax(F2,22=31,4), FCMJmax(F2,22=31,1), and DJ20max(F2,22=23,5), DJ40max(F2,22=17,4), DJ60max(F2,22=18,1) MW FCMJ(F2,22=7,9 ), MWDJ20(F2,22=11,5), MWDJ40(F2,22= 7,65), MPCMJ(F2,22=13,5), MPFCMJ(F2,22=10,9), MPDJ60(F2,22=15,8), HJADJ20(F2,22=7,9), KJVCMJ(F2,22=5,2), KJVDJ60(F2,22=7,1 ), HJV DJ60(F2,22=15,1 ). Discussion / Conclusion: Results showed evidence that, weight lifting exercises can improve mean power in CMJ and DJ from high jumping height (60 cm) and average EMG activity in rectus femoris and gastrocnimius in the same vertical jumps. Traditional weight training method improved performance in kinematic variables during eccentric phase of the vertical jumps. Results are discussed according to results derived from previous studies [3,4]. In conclusion, the sport-specific relationship of the Olympic weight lifting movement with vertical jump, stresses their importance in improving kinetic characteristics and overall mechanical output of the athlete.
© Copyright 2004 Pre-olympic Congress 2004. Thessaloniki, Grécia. de 6 a 11 de Agosto de 2004. Veröffentlicht von ICSSPE. Alle Rechte vorbehalten.