We examine the relation between two devices used in measuring the timing in lower limb complex movement tests for DanceSport athletes, an inertial measurement unit (IMU) and a FitLight Trainer ...device, with the latter regarded as the gold standard method in the field. Four tests are selected to cover the lower limb movements. The research sample comprises 21 experienced dancers from different dance disciplines, performing the four tests with each of their lower limbs. Compared using concurrent validity, the two devices used show great agreement for estimating the total tests' run times, with interclass correlation coefficients between 0.967 and 0.994 for all tests. This agreement is additionally confirmed by Bland-Altman plots. As an alternative to other devices, the IMU sensor has proven to be a precise and suitable device for measuring timing and testing in sports. Its mobility, light weight, and size are advantages of this device in addition to measurement accuracy.
This study was aimed to analyze in detail how the fatigue effects to kinematic parameters of body weight squat exercise (BSQ) by dividing a squat cycle into four different regions. Twenty-one male ...athletes participated in this study. Participants were divided into two groups according to their lower limb muscle ratio (LLMR). The BSQ was performed until participants were unable to continue the exercise due to the fatigue. Linear and angular kinematics were obtained by motion analysis software which has high validity and reliability. There was no significant but had large effect size interaction between fatigue conditions and LLMR groups in terms of knee ROM in the extension phase and hip angular velocity in braking phase of the flexion (0.08 > p >0.05, 0.18 > etarho2 > 0.16). Fatigue condition did not have a significant effect on the duration in the acceleration and braking phases of BSQ (p > 0.05). There were many significant main effects on kinematics in the different regions due to the fatigue (0.01 < p etarho2 > 0.14). In the fatigue condition, there was a polynomial relationship between velocity of shoulder and hip joints (R.sup.2 .sub.flex = 0.82, R.sup.2 .sub.ext = 0.72) rather than linear (R.sup.2 .sub.flex = 0.64, R.sup.2 .sub.ext = 0.53) and coefficient correlations also decreased (r.sub.flex = 0.88 to 0.80, r.sub.ext = 0.92 to 0.73). The sticking region was observed in the non-fatigue condition and disappeared when fatigue occurred. These results suggest that LLMR may be taken into consideration in the squat exercises, joint tracking may vary for velocity-based squat training and pre-test for sticking region observation may be apply with the BSQ.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The purpose of this study was to assess the differences in muscle activation (EMG) and body weight distribution (%BW) between suspension (TRX.sup.TM push-up and TRX.sup.TM inverted row) and ...conventional exercises (bench press and lying barbell row) using different contraction types (isometric and isotonic) and position variations (feet on the ground FG and feet on suspension device FD). It was also used to determine the intensity of the force applied to the straps of the suspension device corresponding to one repetition maximum (1-RM). Twelve male athletes (ages-24.5±4.2 years (mean±standard deviation SD); Height-181.0±6.8 cm; body mass-83.08±6.81 kg) participated in this study. Two suspension devices were used, one for the FD variation and one for the FG variation pectoralis major (PM) and triceps brachii (TRI) activations were assessed during the TRX.sup.TM push-up and bench press exercises. Transversus trapezius (TRA) and biceps brachii (BB) activations were assessed during the TRX.sup.TM inverted row and lying barbell row exercises. The results showed significant differences between exercises (FG and FD variations of TRX.sup.TM push-up and bench press) in PM activities (isometric and isotonic) (pless than or equal to0.05). However, these differences were only observed during isometric TRI activation (pless than or equal to0.05). In the FG and FD variations of the TRX.sup.TM inverted row and lying barbell row exercises, there were only differences in the isometric contractions of the TRA and BB (pless than or equal to0.05). In the suspension device of push-ups and inverted row for the FD variations, 70.5% and 72.64% of 1-RM intensity were obtained, respectively. Similar responses to training intensities and muscle activations can be obtained in suspension exercises and conventional exercises. FD variations of suspension exercises can be more effective in terms of muscle activations than FG variations, and isotonic suspension exercises increase exercise intensity more than isometric suspension exercises.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Abstract
Marković, M, Kukić, F, Dopsaj, M, Kasum, G, Toskić, L, and Zarić, I. Validity of a novel specific wrestling fitness test.
J Strength Cond Res
35(12S): S51–S57, 2021—The specific wrestling ...fitness test (SWFT) is a novel test aiming to estimate the level of physical preparedness of wrestlers; therefore, it should posses an acceptable level of validity. The aim of this study was to investigate an internal, external, and construct validity of SWFT. The sample consisted of 15 national level male wrestlers (age = 22.6 ± 2.3 years, body mass BM = 83.3 ± 6.5 kg, and BM index BMI = 25.36 ± 1.2 kg·m
−2
). They performed the SWFT, specific judo fitness test (SJFT), and specific wrestling performance test (SWPT), each test on a separate day. For each test, performance was evaluated in absolute measure as total number of throws at the end of the test (TnThrows) and relative measure as TnThrows/BM and TnThrows/BMI. Heart rate at the end of the test (HR
0min
) and 1 minute into recovery (HR
1min
) was used as a measure of cardiovascular functionality, whereas specific judo fitness index (SJF
Index
) was used as an indicator of cardiovascular functionality relative to given performance. A correlation and multiple linear regression analyses were used to investigate the internal, external, and construct validity of SWFT. The SWFT_TnThrows/BM had the highest internal validity relative to SJFT_TnThrows/BM (
R2
= 0.722,
p
< 0.001) and the highest external validity relative to SWPT_TnThrows/BM (
r
= 0.846,
p
< 0.001). SWFT_TnThrows/BM predicted SWPT_TnThrows/BM with a large coefficient of determination (
R
2
= 0.818,
p
< 0.001). SWFT_TnThrows/BM is valid and easily attainable predictor of wrestlers' specific physical preparedness and as such is of high practical value.
The aim of this study was to elucidate pattern of attacking actions leading up to goal scoring during the 14 FIFA World Cups from 1966 to 2018. The study analysed 1881 goals scored during a total of ...732 matches. We employed observational methodology design. Before goal analysis began, it was developed the observing protocol in which data related to selected variables, by system of notation, was entered after reviewing each individual goal scoring action. The analysis of all video material was carried out independently by four experienced examiners (three of them are Ph.D in sports science and one is Ph.D. candidate in sports science with at least 7 years of coaching and experience as analyst in football). The inter-and intra-observer reliability presented good level of agreement. The kappa values ranged from 0.82 (goal scoring through open play) to 1.00 (action leading up to goal), showing a very high agreement for all performance variables. Interclass correlation was very high (ICC = 0.966, 95% upper and lower confidence intervals were between 0.933 and 1.00). A statistically significant trend (
p
< 0.05) from 1966 to 2018 was identified towards a higher relative frequency of goals scored from set play and collective actions from open play. The Chi-square did not reveal significant differences in the frequency of goal scoring patterns and goal-scoring zones. The results also revealed that the majority of goals were scored between the 76th and 90th minutes of a match (22.7%), from open play (70.5%), inside the penalty area (54.7%), one touch finishing (62.5%), and collective attacks in open play (55.8%). These findings may provide a possible strategic direction for improving goal-scoring performance in football, as well as practical implementation in World Cup tournament preparation.
To achieve good performance, athletes need to synchronize a series of movements in an optimal manner. One of the indicators used to monitor this is the order of occurrence of relevant events in the ...movement timeline. However, monitoring of this characteristic of rapid movement is practically limited to the laboratory settings, in which motion tracking systems can be used to acquire relevant data. Our motivation is to implement a simple-to-use and robust IMU-based solution suitable for everyday praxis. In this way, repetitive execution of technique can be constantly monitored. This provides augmented feedback to coaches and athletes and is relevant in the context of prevention of stabilization of errors, as well as monitoring for the effects of fatigue. In this research, acceleration and rotational speed signal acquired from a pair of IMUs (Inertial Measurement Unit) is used for detection of the time of occurrence of events. The research included 165 individual strikes performed by 14 elite and national-level karate competitors. All strikes were classified as slow, average, or fast based on the achieved maximal velocity of the hand. A Kruskal–Wallis test revealed significant general differences in the order of occurrence of hand acceleration start, maximal hand velocity, maximal body velocity, maximal hand acceleration, maximal body acceleration, and vertical movement onset between the groups. Partial differences were determined using a Mann–Whitney test. This paper determines the differences in the temporal structure of the reverse punch in relation to the achieved maximal velocity of the hand as a performance indicator. Detecting the time of occurrence of events using IMUs is a new method for measuring motion synchronization that provides a new insight into the coordination of articulated human movements. Such application of IMU can provide additional information about the studied structure of rapid discrete movements in various sporting activities that are otherwise imperceptible to human senses.
Athletes differ among themselves and one of the main differences is observed in relation to body shape and composition. Achieving top sports performance requires more standardization in the processes ...of training and development of a unique methodology for individualizing the control specific adaptation of athletes. The aim of this study is to establish reference data for the most sensitive variables to define the amount and structure of body fat in female athletes in individual sports. The sample included 895 females, divided in: a control group (Cont) of young females (N = 688); International (N = 113), and National level female athletes (N = 94) in 13 individual sports. Four variables described the structureof of body fat: Percentage of body fat (PBF), Body Fat Mass Index (BFMI), Protein Fat Index (PFI) and Index of Body Composition (IBC). Results showed that considering the control group, female athletes have all examined Body Fat variables statistically significantly different (BFMI and PBF are lower, p = 0.011 and p = 0.000, while PFI and IBC are higher, p = 0.000, respectively). Female athletes are also statistically significantly different in relation to the level of competition (p = 0.000), and the investigated variables are responsible for 17.7 % of the variability of the difference between the groups. Competitively more successful female athletes have higher IBC (lower percentage of fat per overall body volume, p = 0.013), as well as, a statistically significantly higher protein mass in relation to body fat mass (PFI, p = 0.018). The most sensitive variables for defining body fat differences between the examined individual sports were IBC, with an influence of 37.9 %, then PFI (32.4 %), then PBF (22.8 %), and finally BFMI, with an influence of 11.4 % on the differences. Based on the results of this study, IBC and PFI are variables that have shown useful scientific-methodological potential for research in the future.
Purpose: Leisure-time physical activity (LTPA) has always been very important for the maintenance and improvement of body composition. Thus, the aim of this study was to examine if the frequency and ...volume of LTPA (F-LTPA and V-LTPA) were related to indices of body composition in police officers. Method: A physical activity questionnaire was used to collect data from 346 male police officers regarding their F-LTPA and V-LTPA. They were divided into four groups relative to the frequency, and four groups relative to the volume of LTPA, labeled as inactive, seldom active, moderately active and very active for each LTPA indicator. Percent body fat (PBF), skeletal muscle mass (PSMM), skeletal muscle mass index (SMMI) and body fat mass index (BFMI) were assessed. Correlation analyses investigated associations and multivariate analysis of variance analysed the differences between body composition and LTPA, with significance set at p < .05. Results: The F-LTPA correlated (p < .001) to PBF (r = −0.306), BFMI (r = −0.289), PSMM (r = 0.309) and SMMI (r = −0.138, p = .010). The V-LTPA correlated (p < .001) to PBF (r = −0.370), BFMI (r = −0.348), PSMM (r = 0.311), and SMMI (r = −0.106, p = .049). The differences that occurred between more and less active police officers, whereby those who were very active had lower values of PBF and BFMI and higher values of PSMM and SMMI regardless of the frequency and volume of LTPA. PBF and PSMM were more affected by LTPA than SMMI and BFMI. Conclusions: F-LTPA and V-LTPA were considered important for police officers, whereby F-LTPA was related to muscle and V-LTPA to fat parameters of body composition.
In water polo, the team’s technical and tactical performance is determined by the sum of the players’ activities. This study aimed to investigate the playing offensive performance of an Italian First ...League team performed during all matches (n = 19) of the 2021/22 championship using the Team Sport Assessment Procedure (TSAP). For all subjects (n = 15), gaining possession of the ball (received balls (RB) and conquered balls (CB)) and disposing of the ball (neutral balls (NB); lost balls (LB); offensive ball (OB) and successful Shots (SS)) parameters, as well as volume of play (VP), efficiency index (EI) and performance score (PS) indexes, were analyzed in relation to the playing positions, season phase, match location and final score difference. Multiple linear regression showed a significant association between the playing position and VP and PS. Perimetral players showed the highest VP (65%) and PS (66%) values, and center defenders showed the highest values of CB (30%), while center forwards gained the highest amount of exclusion when handling the ball (48%). Although they were not significant, the other contextual factors showed that season phase and match location could affect the TSAP indexes. For water polo coaches, the TSAP represents an effective tool to assess how players interpret the match.
Toskić, LD, Dopsaj, MJ, Marković, MR, Toskić, DR, Ignjatović, AM. Mechanical and contractile properties of knee joint muscles measured by the method of tensiomyography in differently trained men and ...women. J Strength Cond Res 36(6): 1532-1539, 2022-The aim of this study was to investigate the differences in mechanical and contractile properties of knee joint flexor and extensor muscles between differently trained men and women, using tensiomyography (TMG). The sample consisted of 159 subjects (84 men and 75 women), who were assigned to one of 5 groups according to the following levels and types of their physical activity: physically inactive, physically active nonathletes, strength and power athletes, endurance athletes, and team sports athletes. Measurements were performed on the following knee flexor and extensor muscles of the dominant leg: rectus femoris, vastus medialis, vastus lateralis, biceps femoris, and semitendinosus. The results showed significant differences in contraction time-Tc (F = 1.911, p = 0.010) and delay time-Td (F = 1.989, p = 0.007) parameters between differently trained men and women, whereas in other TMG parameters, there were no differences between groups. It is indicated that physical activities characteristic of strength and power sports (combat sports and sprint disciplines) could lead to an increased speed of twitch force generation and fast twitch muscle fibers, and that almost any regular, systematic, and planned physical activity leads to increased muscle responsiveness. Obtained results also indicated that TMG parameters do not have enough specific discriminatory power for detecting differences between differently trained young adults.
PDF
