Król, H and Gołaś, A. Effect of barbell weight on the structure of the flat bench press. J Strength Cond Res 31(5): 1321–1337, 2017—In this study, we have used the multimodular measuring system SMART. The system consisted of 6 infrared cameras and a wireless module to measure muscle bioelectric activity. In addition, the path of the barbell was measured with a special device called the pantograph. Our study concerns the change in the structure of the flat bench press when the weight of the barbell is increased. The research on the bench press technique included both the causes of the motion: the internal structure of the movement and the external kinematic structure showing the effects of the motion, i.e., all the characteristics of the movement. Twenty healthy, male recreational weight trainers with at least 1 year of lifting experience (the mean ± SD = 3.3 ± 1.6 years) were recruited for this study. The subjects had a mean body mass of 80.2 ± 8.6 kg, an average height of 1.77 ± 0.08 m, and their average age was 24.7 ± 0.9 years. In the measuring session, the participants performed consecutive sets of a single repetition of bench pressing with an increasing load (about 70, 80, 90, and 100% of their 1 repetition maximum [1RM]). The results showed a significant change in the phase structure of the bench press, as the barbell weight was increased. While doing the bench press at a 100% 1RM load, the pectoralis major changes from being the prime mover to being the supportive prime mover. At the same time, the role of the prime mover is taken on by the deltoideus anterior. The triceps brachii, in particular, clearly shows a greater involvement.

No abstract

The main objective of the study was to determine to what degree higher muscular activity, achieved by increased load in the extension phase (eccentric muscle action) of the vertical jump, affects the efficiency of the vertical jump. Sixteen elite biathletes participated in this investigation. The biathletes performed tests that consisted of five, single “maximal” vertical jumps (counter movement jump – CMJ) and five, single vertical jumps, in which the task was to touch a bar placed over the jumping biathletes (specific task counter movement jump – SCMJ). Then, they performed five, single drop jumps from an elevation of 0.4m (DJ). Ground reaction forces were registered using the KISTLER 9182C force platform. MVJ software was used for signal processing (Król, 1999) and enabling calculations for kinematic and kinetic parameters of the subject’s jump movements (on-line system). The results indicate that only height of the jump (h) and mean power (Pmean) during the takeoff are statistically significant. Both h and Pmean are higher in the DJ. The results of this study may indicate that elite biathletes are well adapted to eccentric work of the lower limbs, thus reaching greater values of power during the drop jump. These neuromuscular adaptive changes may allow for a more dynamic and efficient running technique.

No abstract

Introduction.In sport technique studies, motion features can be useful as they have a certain defined measure [1]. In this work, we examined the following three features: the structure of the movement (all the characteristics of the movement), the fluency of the movement, and the rhythm of the movement. The aim of the study was to determine the usefulness of the selected movement features in the evaluation of the flat bench press. The protocol of the study included a flat bench press with free weights and a "touch-and-go" technique. Material and methods. The study involved twenty healthy men; however, only two were selected for analysis. The first subject was a 25-year-old powerlifter (body mass = 95 kg; body height = 182 cm; 1-RM in flat bench press = 145 kg). The second one was a 25-year-old bodybuilder (body mass = 77 kg; body height = 175 cm; 1-RM in flat bench press = 100 kg). The subjects performed consecutive sets of a single repetition of flat bench pressing with an increasing load (70, 80, 90, and 100% 1-RM, with the anticipated maximum weight), until the completion of one repetition maximum. Multidimensional movement analysis was made with the measuring system Smart-E (BTS, Italy), which consisted of six infrared cameras (120 Hz) and a wireless module to measure muscle bioelectric activity (Pocket EMG). Results. It was demonstrated that the internal structure of the bench press performed by the bodybuilder and the powerlifter was different. As the time-history of barbell kinematics (the acceleration-time curve) showed, with increased loading of the barbell, the rhythm of the flat bench press changed, and the fluidity of the movement worsened.

Introduction. Some of the most important roles of coaches are organising the technical training for evaluating movement technique and indicating errors as gymnasts perform the elements of this movement. This can only be applied in individual gymnasts [2,3], and there are gaps in our knowledge about the details of the technique of individual gymnasts. Therefore, due to the structural complexity of acrobatic elements, the evaluation of a technique should precisely locate errors indicated in specific phases of the exercise. Material and methods. In this paper, the results of the atypical back tucked somersault and counter movement jump of one of the participants are reported on. This participant was a 16-year-old female gymnast with a body mass of 51 kg and a height of 156 cm. While coaches use a subjective qualitative analysis of the sporting movement to determine what advice must be given, a sports biomechanics researcher must make use of objective quantitative data. In our study, we have used the multimodular measuring system SMART when studying the structure of the acrobatic jumps, and we conducted a complex analysis of these exercises. Results. These exercise approaches may be used to achieve important training goals. It seems logical, therefore, that physical educators, coaches, and athletes should look to biomechanics for a scientific basis for the analysis of the individual techniques used in sports. As for practical implications, we recommend that coaches and physical education educators carefully monitor the gymnast's leg joints and avoid extension of the knee and ankle at the counter movement phase during standing acrobatic jumps.

No abstract

The aim of this study was to investigate the relationships between the internal and external structure of basic acrobatic jumps. Eleven healthy elite artistic gymnasts (9 female, 2 male) participated in this study. Participants performed the following basic ‘acrobatic’ jumps: a tucked backward somersault (TS), a piked backward somersault (PS), and a countermovement jump (CMJ). Furthermore, female gymnasts also performed the backward handspring (HS), taking off and then landing on their hands in the same place – a specific jump only for women. All jumps were initiated from a stationary upright posture and with an arms swing. Six infrared cameras, synchronized with a module for wireless measurement of the electrical activity of eight muscles, and the force plate were used. Infrared camera-recordings were made in order to obtain kinematic variables describing the movement structure of the acrobatic jumps. These variables may explain the characteristics of muscle activation (the internal structure of the movement) and ground reaction force (the external-kinetic structure of the movement). However, for various technical reasons, it was not possible to register all the specified jumps in the protocol. Moreover, the distribution normalities, estimated by the Kolmogorov-Smirnov test, differed between variables. Therefore, to compare the data, the pair-wise nonparametric Wilcoxon Signed-Ranks Test was applied. The CMJ showed the highest level of vertical impulse, velocity, and displacement followed by the TS, PS, and HS. In the take-off phase of acrobatic jumps with rotation the average muscle activation levels of the biceps femoris were significantly higher and of the rectus femoris significantly lower than in the countermovement jump.