1,721,183 research outputs found
Effects of intra-cyclic velocity variations on the drag exerted by different swimming parachutes
No full textSwimming parachutes are often used as a tool for resisted swimming training. However, little is known on their behavior in terms of exerted drag as a consequence of intra-cyclic velocity fluctuations. This study aimed to assess the drag provided by two swimming parachutes of different shape, also characterized by different volumes and cross-sectional areas, under conditions of velocity variations in the range of those occurring in swimming. A flat square shaped parachute (FLAT, cross-sectional area and volume: 400 cm; 0.12 l) and a truncated cone shaped parachute (CONE, 380 cm; 7.15 l) were passively towed: 1) at constant velocities ranging from 1.0 to 2.2 m/s, and 2) with velocity fluctuations from 10 to 40 % around a mean of 1.6 m/s. At constant velocities, FLAT showed 0.1 N (at 1.0 m/s) to 10.8 N (at 2.2 m/s) higher drag than CONE. For both parachutes, the average drag showed trivial differences between constant and any fluctuating velocity. Conversely, the maximum drag values were higher under conditions of velocity fluctuations than the respective values estimated under stationary instantaneous velocity, although this was observed in CONE only. These findings suggest that swimmers and coaches can select the parachute characteristics based on whether the focus is on increasing/decreasing the average drag or regulating the maximum resistance provided
Impact of technical and physical performance on match outcome over five elite European soccer seasons
Full text linkThe technical and physical performance, a key part of overall soccer performance, tend to evolve due to changes in game rules, playing styles, and training methodology. Nevertheless, little has been reported in the literature on how match performance has changed over time in elite championships and leagues. Thus, this study aimed to assess the impact of selected technical and physical team performance indicators on match outcome over five seasons in the Russian Premier League
Sprint start kinematics during competition in elite and world-class male and female sprinters
No full textThe start kinematics has been reported to differ between male and female sprinters. This study aimed to determine whether kinematic differences between the sexes are attributable to an effect of sex per se, or rather to the absolute performance level of the sprinters, quantified by the 100-m time. A total of 20 sprinters (10 M, 10 F), including world-class and elite athletes, were assessed. Start phases from the “set” position to the first two steps were analysed. Linear regression analyses showed a few significant differences between sexes when taking into account the effect of performance level: M had shorter pushing phase duration, higher horizontal velocity at block clearing, and shorter contact times of the first two steps. Conversely, the performance level affected most of the examined parameters: faster sprinters showed the centre of mass (CM) closer to the ground and a more flexed front knee in the “set” position, longer pushing phase duration, lower vertical velocity of the CM at block clearing, and longer contact times and shorter flight times in the first two steps. These findings suggest that the start kinematics is only partially affected by the sex of sprinters, whereas a bigger role is played by their performance level
Relationships Between Muscle Architecture, Deadlift Performance, and Maximal Isometric Force Produced at the Midthigh and Midshin Pull in Resistance-Trained Individuals
Full text linkThe aim of this study was to investigate the relationships between muscle architecture, lower-body power, and maximal isometric force produced at midthigh pull (MTP), and at midshin pull (MSP). Twenty experienced resistance-trained men (age = 25.5 ± 3.2 years; body mass = 86.9 ± 12.4 kg; body height = 178.0 ± 5.3 cm) were tested for deadlift 1 repetition maximum (1RM), countermovement jump (CMJ), peak force (PF), and rate of force development (pRFD20) produced at isometric MTP and isometric MSP. Subjects were also assessed for architecture of vastus lateralis (VL), and physiological muscle thickness, pennation angle, and fascicle length (FL) were measured. Pearson's correlation coefficients were calculated to assess the relationships between variables. In addition, differences between MTP and MSP were assessed using paired-sample t-tests. A significant (p < 0.05) difference was detected on the correlation between deadlift 1RM and MSP (r = 0.78; p < 0.001) compared with MTP (r = 0.55; p = 0.012). Moderate correlations were observed between MSP PF and VLFL (r = 0.55; p = 0.011). Midshin pull pRFD20 was the only parameter significantly correlated with CMJ (r = 0.50; p = 0.048). Significantly higher PF and pRFD20 were recorded in MTP compared with MSP (p = 0.007 and p = 0.003, respectively). The present results show that force produced from the floor position may be more important than force produced from a position that mimics the second pull of the clean for deadlift and vertical jump performances. Coaches and scientific investigators should consider using MSP to assess isometric PF using a test correlated with both muscle architecture and dynamic performances
Two vs. One Resistance Exercise Sessions in One Day: Acute Effects on Recovery and Performance
No full textPurpose: The purpose of this study was to compare the recovery response of one resistance training session (1TRS) vs. two resistance training sessions (2TRS) performed in 1 day, on upper body performance, muscle morphology and muscle soreness in trained men. Methods: Twenty-four resistance trained men were randomly assigned into a 1TRS group (N = 12; age = 25.0 ± 2.4 years; body mass = 87.6 ± 14.0 kg; height = 177.1 ± 4.9 cm) or into a 2TRS group (N = 10; age = 24.4 ± 1.6 years; body mass = 81.1 ± 5.6 kg; height = 176.6 ± 6.7 cm). 1TRS performed one training session involving eight sets of 10 reps at 70% of 1RM at the bench press, while 2TRS group divided the same training volume in two workouts, with a recovery time of 4 hr. Performance [bench press throw power (BTP) and isometric bench press (IBP)] and muscle thickness of pectoralis major (PECMT) were assessed at baseline (BL), 15-min, 24-hr and 48-hr post-exercise. Results: Training intensity was significantly higher in 2TRS compared to 1TRS (p < .001). Faster recovery rates were detected for BTP (p = .039) and PECMT (p = .05) in 2TRS compared to 1TRS. Both BTP and PECMT were significantly more affected (p < .05) in 1TRS than in 2TRS at 24 h. Conclusions: Results indicate that the recovery process may be accelerated by splitting a high resistance training volume into two different training sessions performed in 1 day
Body fat distribution in Italian, Spanish and Estonian children
No full textObesity, and especially abdominal obesity, is related to an increased risk of cardiovascular and metabolic diseases. Many disturbances related to abdominal obesity show their onset in the childhood years. Thus, during these years, it’s important to properly monitor body fat and its distribution. The aim of this study was to investigate the fat patterning in Italian, Estonian and Spanish schoolchildren. The sample consisted of 2024 children (1005 boys and 1019 girls) aged 6 to 11 years. Anthropometric measurements included triceps, biceps, subscapular, supraspinal, suprailiac, thigh, medial and lateral calf skinfold thicknesses, height and humerus width. Two indices of central adiposity and frame index were calculated. Italian children of both sexes showed higher values of skinfold thicknesses than Estonian and Spanish children, while Spanish children showed overall higher values of central adiposity indexes, followed by Italian children. On the contrary, Estonian children showed higher values of the frame index and lower central adiposity. From a public health perspective, a priority will be the development of programs aiming to prevent obesity, in particular when a central pattern of fat distribution emerges during childhood
Sex differences in perceived physical activity characteristics in 11-19 years old italian students
No full textPurpose. This study aimed to investigate sex and age differences in selected physical characteristics assessed with questionnaires in a cohort of middle and high school students.
Methods. 1051 students (497 girls and 654 boys) aged 11 to 19 years completed the following questionnaires: Physical Activity Questionnaire for Adolescents (PAQ-A), Task and Ego Orientation in Physical Education Questionnaire (TEOSQ), Physical Activity Enjoyment Scale Questionnaire (PACES), Teacher-Initiated Motivational Climate in Physical Education Questionnaire (TIMCPEQ), Physical Self Description Questionnaire (PSDQ), and Psychobiosocial states questionnaire (PBS). For all questionnaires, scores were compared by sex and age with two-way ANOVAs.
Results. Overall, boys showed higher scores than girls in the PAQ-A, TEOSQ (ego orientation), TIMCPEQ, PBS (both pleasant and unpleasant descriptors), PACES (positive items), and PSDQ. Conversely, girls showed higher scores than boys in the PACES (negative items).
A trend of questionnaires scores to decrease across ages was observed, both in boys and girls, in the PAQ-A, PBS (pleasant descriptors), and PACES (positive items). Furthermore, decreases across ages of TEOSQ (task orientation) and PACES (negative items) were observed only in boys, while the PSDQ score decreased only in girls. Finally, boys showed an increase across age of the TEOSQ (ego orientation) score.
Conclusions. The present study confirms a decrease of motivation towards PA and PA enjoyment across adolescence and in particular in the transition between the middle and high school (at age 14). The study findings provide suggestions to PE teachers about the importance of using motivational strategies towards students, differentiated by sex and age groups
A kinematic comparison between long-line and cross-court top spin forehand in competitive table tennis players
No full textThe aim of the present study was to compare the biomechanical characteristics of the table tennis top spin shot when played cross-court (CC) or long-line (LL) in competitive table tennis players. Seven national level players respectively completed 10 long-line and 10 cross-court top spin shots responding to a standard ball machine. A stereophotogrammetric system was used to track body segments while executing the motion. Significantly more flexed right knee and elbow angles were measured at the moment of maximum velocity of the racket (MMV) in LL. In addition, significantly greater angles between the feet and the table and between the shoulders and the table at the MMV, indicated more pronounced rotation angles of the lower upper and upper-body in LL compared to CC with respect to the table. A higher inclination of the racket at the MMV was found in LL. The elbow flexion and the racket inclination may be associated to the direction of the shot. The present findings show that kinematic differences exist between the LL and the CC topspin forehand in competitive table tennis players. Coaches should be aware of these differences to adopt the optimal teaching strategies and to reproduce proper joint angles during training
Technical and physical performance across five consecutive seasons in elite European Soccer
No full textThe technical and physical demands of elite soccer match-play may vary considerably across a season and from season-to-season in relation to a myriad of factors. The aim of this study was to investigate the technical and physical performance trends over five consecutive seasons (2016–2021) for twenty-two soccer players from a team participating in an elite European league, the Russian Premier League (RPL). Match data were recorded and analysed via an Optical Tracking System, and a selection of technical and physical performance variables were examined. From matches analysed, we observed small within-season changes (ES 0.17 to 0.37) for technical performance variables, and small to moderate changes (ES 0.31 to 0.86) for physical performance variables. Dribbles, percentage of successful dribbles, total distance covered, high-intensity and sprint distances, and maximal acceleration showed an average increase from the 2016–2017 to the 2018–2019 season, followed by a decrease in the subsequent seasons. Conversely, tackles, high-intensity accelerations and peak acceleration showed a decreasing trend from the 2016–2017 to the 2020–2021 season. Moderate to large correlations (r = −0.58 to 0.46) were apparent between changes in technical and physical variables. In summary, we observed between-season changes in match technical and physical variables in a RPL team, while there were no differences between the first and second phases of the season. The present findings may provide coaches with knowledge about long-term variations in technical and physical match performance, that can be practically useful to assess and interpret change in individual and team performance
A Comparison between Male and Female Athletes in Relative Strength and Power Performances
Full text linkThe aim of this study was to compare male vs. female athletes in strength and power performance relative to body mass (BM) and lean body mass (LBM) and to investigate the relationships between muscle architecture and strength in both genders. Sixteen men (age = 26.4 ± 5.0 years; body mass = 88.9 ± 16.6 kg; height = 177.6 ± 9.3 cm) and fourteen women (age = 25.1 ± 3.2 years; body mass = 58.1 ± 9.1 kg; height = 161.7 ± 4.8 cm) were tested for body composition and muscle thickness (MT) of vastus lateralis muscle (VT), pectoralis major (PEC), and trapezius (TRAP). In addition, participants were tested for lower body power at countermovement jump (CMJP) and upper-body power at bench press throw (BPT). Participants were also assessed for one repetition maximum (1RM) at bench press (1RMBP), deadlift (1RMDE), and squat (1RMSQ). Significantly greater (p < 0.01) MT of the VL, PEC and TRAP muscles and LBM were detected in men compared to women. Significantly greater (p < 0.05) 1RMBP and BPT adjusted for LBM were detected in men than in women. No significant gender differences after adjusting for LBM were detected for 1RMSQ (p = 0.945); 1RMDE (p = 0.472) and CMJP (p = 0.656). Significantly greater (p < 0.05) results in all performance assessments adjusted for MT of the specific muscles, were detected in males compared to females. Superior performances adjusted for MT and LBM in men compared to women, may be related to gender differences in muscle morphology and LBM distribution, respectively
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