Browse

You are looking at 81 - 90 of 2,685 items for :

  • Sports and Recreation, other x
Clear All
Open access

Rubén Ayarra, Fabio Yuzo Nakamura, Aitor Iturricastillo, Daniel Castillo and Javier Yanci

Abstract

The purpose of the present study was to describe performance in acceleration capacity, change of direction ability, vertical jump, horizontal jump, repeated sprint ability, and endurance (Yo-Yo Intermittent Recovery Test Level 1) in futsal players, and analyze the differences according to competitive categories or levels. The total sample (n = 40) was divided into three groups depending on the category in which the participants competed: Second Division B (n = 15), Third Division (n = 12) and juniors (n = 13). All the tests were performed with participants’ regular competition shoes and on the usual playing surface, in an indoor pavilion with a floating wood floor. The results of the study did not show significant differences in acceleration capacity (5 and 15 m) or change of direction ability among the different categories. In contrast, significant differences were found among the categories with regard to horizontal jump and vertical jump capacity (p < 0.05); but not in all the variables analyzed. Performance in repeat sprint ability varied significantly among the different categories in 30 m (p < 0.01) but not in 5 m (p > 0.05). The distance covered in the Yo-Yo Intermittent Recovery Test Level 1 by the Second Division B and the Third Division groups was greater than that covered by the junior group. In the light of these results repeated sprint ability and aerobic endurance could be two discriminating qualities of the competitive level among different futsal categories.

Open access

Meizi Wang, Lin Fu, Yaodong Gu, Qichang Mei, Fengqin Fu and Justin Fernandez

Abstract

This study investigated differences of lower limb kinematics and muscle activity during table tennis topspin loop against backspin movements between elite players (EPs) and amateur players (APs). Ten EPs and ten APs performed crosscourt backhand loop movements against the backspin ball with maximal power. Vicon motion analysis and a MEGA ME6000 system was used to capture kinematics and surface EMG data. The motion was divided into two phases, including the backswing and swing. The joints’ flexion and extension angle tendency between EPs and APs differed significantly. The coefficient of multiple correlation (CMC) values for EPs were all beyond 0.9, indicating high similarity of joint angles change. APs presented moderate similarity with CMC values from 0.5 to 0.75. Compared to APs, EPs presented larger ankle eversion, knee and hip flexion at the beginning moment of the backswing. In the sEMG test, EPs presented smaller standardized AEMG (average electromyography) of the lower limb muscles in the rectus femoris and tibia anterior on both sides. Additionally, the maximum activation of each muscle for EPs was smaller and MPF (mean power frequency) of the lower limb was greater during the whole movement. The present study revealed that EPs could complete this technical motion more economically than APs, meanwhile, EPs were more efficient in muscle usage and showed better balance ability.

Open access

Aleksandra Kisilewicz, Marcin Janusiak, Rafał Szafraniec, Małgorzata Smoter, Bogdan Ciszek, Pascal Madeleine, César Fernández-de-Las-Peñas and Adam Kawczyński

Abstract

The study aimed to assess the effects of compression trigger point therapy on the stiffness of the trapezius muscle in professional basketball players (Part A), and the reliability of the MyotonPRO device in clinical evaluation of athletes (Part B). Twelve professional basketball players participated in Part A of the study (mean age: 19.8 ± 2.4 years, body height 197 ± 8.2 cm, body mass: 91.8 ± 11.8 kg), with unilateral neck or shoulder pain at the dominant side. Part B tested twelve right-handed male athletes (mean ± SD; age: 20.4 ± 1.2 years; body height: 178.6 ± 7.7 cm; body mass: 73.2 ± 12.6 kg). Stiffness measurements were obtained directly before and after a single session trigger point compression therapy. Measurements were performed bilaterally over 5 points covering the trapezius muscle. The effects were evaluated using a full-factorial repeated measure ANOVA and the Bonferroni post-hoc test for equal variance. A p-value < .05 was considered significant. The RM ANOVA revealed a significant decrease in muscle stiffness for the upper trapezius muscle. Specifically, muscle stiffness decreased from 243.7 ± 30.5 to 215.0 ± 48.5 N/m (11.8%), (p = .008) (Part A). The test-retest relative reliability of trapezius muscle stiffness was found to be high (ICC from 0.821 to 0.913 for measurement points). The average SEM was 23.59 N/m and the MDC 65.34 N/m, respectively (Part B). The present study showed that a single session of compression trigger point therapy can be used to significantly decrease the stiffness of the upper trapezius among professional basketball players.

Open access

Wei-Hsun Tai, Li-I Wang and Hsien-Te Peng

Abstract

The purpose of this study was to determine the differences in biomechanical characteristics between one- and two-legged running vertical jumps (1-LRVJ and 2-LRVJ). Ten male college volleyball players voluntarily participated in this study. Two running vertical jumps used in volleyball were randomly performed. Three trials for each type of the running vertical jump were recorded for each participant. Data were collected using six infra-red Qualisys motion-capture cameras at a 180-Hz sampling rate and two AMTI force platforms at an 1800-Hz sampling rate. Jump height in the 2-LRVJ was significantly higher than that in the 1-LRVJ (p < 0.05). In the take-off phase, knee and hip extension impulses for the 1-LRVJ were significantly greater than those for the 2-LRVJ (p < 0.05). These results suggest that the 1-LRVJ produced greater leg stiffness than the 2-LRVJ did. We found that the 1-LRVJ caused greater lower-extremity stiffness and impulse compared to the 2-LRVJ, which is beneficial in the stretch-shortening cycle, and thus the more focus on practicing 1-LRVJs is recommended for coaches and athletes.

Open access

José M. Pratas, Anna Volossovitch and Ana I. Carita

Abstract

The aim of this study was to examine the sequences of the first two goals scored in soccer matches in accordance with a range of different match contexts. Data from 1506 matches played in the Portuguese Premier League during six consecutive competitive seasons (2009-10 to 2014-2015) were analysed using descriptive statistics and the chi-square test in order to verify the association between variables and a Cox regression analysis was used to predict the time the second goal was scored in function of the time of the first goal scored in the match and the scoreline. The results revealed a higher frequency of the second goals being scored in the second half of a match (58%) and in the last 5 min periods of each half. A positive association was found for home teams and score-doubling goals (58%), as well as for away teams and score-equalizing goals (56%). For home and away teams the score-doubling goal of a match was strongly and positively associated with a win outcome for home (93%) and away teams (92%), while the score-equalizing goals were associated with a draw (home and away teams: 44%) and loss outcome (home: 33% and away teams: 32%). Finally, the Cox model showed that if the first goal was scored in the second half of the match, the probability of the second goal being scored was three times higher compared to the first half.

Open access

David Bellar, Cory Etheredge and Lawrence W. Judge

Abstract

Suspension exercise systems are being used in strength and conditioning facilities, fitness centers, rehabilitation centers and home gyms. Though some evidence exists regarding the impact of training with these systems, more work is needed for a better understanding. The purpose of the present investigation was to examine the acute effects of an exercise session with 2 (hands only) and 4 straps (hands and feet) in the push-up exercise compared to a work-matched bench press exercise session. The participants for this repeated measures, cross-over investigation were 18 healthy college-aged males (age: 24.8 ± 3.5 yrs, body mass: 81.8 ± 7.8 kg, body height: 178.9 ± 4.5 cm). The conditions were 6 sets of 10 repetitions of suspension push-ups using two straps (DUAL) for the hands, fours straps (QUAD) for hands and feet and a traditional bench press exercise matched to the average resistance during the suspension push-up. The participants performed all repetitions at a controlled cadence. Expired gases, and heart rate were monitored continuously during the exercise session. Pre and post exercise saliva samples were collected to quantify changes in testosterone and cortisol. Upper body isometric strength tests ( UBIST) were performed (Post, 1 hr, 24 hr, 48 hr) to evaluate changes in force production during recovery. Data analysis via repeated measures ANOVA revealed a significant trend for increased oxygen consumption in the QUAD condition compared to the bench press (p = 0.019). Additionally, both suspension conditions resulted in a reduced respiratory exchange ratio as compared to the bench press (p < 0.05). A significant main effect was noted for time in all conditions regarding isometric strength (p < 0.001), but no differences between conditions were revealed. Testosterone and cortisol responses did not differ between conditions. Based upon these data, it appears that when matched for work, suspension exercise results in equivalent reductions in muscle force, but greater oxygen consumption compared to isotonic exercise.

Open access

Irineu Loturco, Ian Jeffreys, Ronaldo Kobal, César C. Cal Abad, Rodrigo Ramirez-Campillo, Vinicius Zanetti, Lucas A. Pereira and Fábio Y. Nakamura

Abstract

This study aimed to compare vertical jump ability (squat-jump [SJ] and countermovement-jump [CMJ]), relative to body mass mean propulsive power in the jump-squat (MPP-REL JS), and the 0-5, 5-10, and 10-20 m acceleration and speed among soccer players from the same professional club, divided into age-categories (U15 [n = 20], U17 [n = 53], U20 [n = 22] and senior [n = 25] players). The tests were performed at the start of the preseason in indoor facilities. The magnitude-based inference approach and the standardized differences (based on effect sizes) were used to compare the age-groups. The SJ, CMJ, and MPP-REL JS increased across the age-groups up to U20, the latter being similar to senior players. Interestingly, the 0-5 m acceleration was likely and possibly higher in U15 players compared to U17 and senior players. Although soccer athletes improve their unloaded and loaded jump abilities across the age-categories (plateauing during adulthood), the same does not hold true for acceleration capacity, from the early phases of players’ development (i.e., U15). Strength and conditioning professionals should seek effective strategies to minimize impairment in maximal acceleration performance of elite soccer players throughout their prospective training programs.

Open access

Andrzej Lewandowski, Marcin Kowalewski, Tomasz Kowalik and Zuzanna Piekorz

Abstract

Study aim: The purpose of this study was to investigate changes in the power output and major morphological characteristics during the competition phase. We hypothesised that substantial overloads occurring during this stage cause a decrease in body mass, fat and power output levels in the cyclists.

Material and methods: Nine members from an affiliated Professional Cycling Group ActiveJet Team were observed during the period between January and September. Their mean age was calculated as 25.1 ± 1.6 years. Each month the main somatic fea­tures were determined and the BMI and Rohrer index were measured. The level of adipose tissue was checked using the Tanita BC-418 Ma and the Schoeberer Rad Messtechnik SRM training system was employed to record the maximum level of power output. The following tests were used to collect data: Shapiro-Wilk and ANOVA (assessment of the distribution of variables), Duncan (assessment of the changes of variables), and Pearson correlation coefficient (assessment of power dependence and morphological features). A significance coefficient of α = 0.05 was assumed.

Results: The research of the studied group revealed a steady decrease in the body mass and fat percentage but no significant differences in power output levels. Its peak was reached in the middle of the starting phase (1195.3 ± 222.3 W) and the lowest level was noted during the last month of our observation (1114.1 ± 152.1 W; D = 81.2 W, p = 0.088). Correlations were found between body mass, fat composition and power output levels: moderate for mass (r = 0.383-0.778) and fat (r = 0.352-0.629) content to power output and small negative for height to power output. In most cases, however, they were either weak or low (r = -0.017-0.339).

Conclusions: Significant changes in the morphological characteristics (body weight 70.2 ± 6.4-69.2 ± 5.9 kg, p < 0.001; BMI 21.4 ± 1.9-21.1 ± 1.7, p < 0.001; Rohrer index 1.18 ± 0.11-1.16 ± 0.10, p < 0.001; fat 9.2 ± 3.2-8.2 ± 2.3, p < 0.001) and no differences in power output combined (1151.0 ± 272.4-1114.1 ± 152.1 W, p = 0.434) with medium correlations of these determinants (body height - 2.53-0.354; body weight 0.383-0.778; fat 0.352-0.629) indicate the significance of motor charac­teristics in road racing cyclists. Thus levels in its competency and performance outcomes are determined to a greater extent by factors other than the somatic characteristics.

Open access

Shahrzad Zandi, Reza Rajabi, Mohammadali Mohseni-Bandpei and Hooman Minoonejad

Abstract

Study aim: The aim of this study was to investigate the reliability of the electromyographic activity of selected shoulder girdle muscles during the overhead volleyball throw.

Material and methods: The test-retest reliability of EMG activity of selected shoulder muscles during an overhead volleyball throw was investigated in 15 non-symptomatic university-level female volleyball players for within-day sessions (with a one-hour interval) and between-day sessions (with a one-week interval). Time broadness (a measure of coordination) and root mean square of electromyography signals were obtained. Results: A high within-day (0.85-0.99) and moderate to high between-day (0.68-0.93) intraclass correlation coefficient for normalized RMS activity and a high within-day and between-day intraclass correlation coefficient (0.94 and 0.80; respectively) for time broadness were observed. Absolute agreement of measurements had small values (0.15-1.96). Trends toward higher intraclass correlation coefficient values and lower standard error of measurements, minimum detectable change, mean differ­ences and limits of agreements values were observed for within-day reliability in all test results compared with between-day reliability.

Conclusions: The results suggest that the activity of shoulder muscles can be reliably assessed during the overhead volleyball throw with the described procedure both in the amplitude domain (normalized average root mean square) and the time domain (time broadness of the activities).

Open access

Ben Serrien and Jean-Pierre Baeyens

Abstract

The proximal-to-distal sequence has previously been discussed in the light of performance and injury prevention. Sports biomechanics literature in general, and in team handball in specific, has claimed to be of importance to inform coaches on what constitutes a ‘good’ technical performance. However, hitherto no prospective studies exist on how this information may be used and this may in part be due to the general small sample sizes. We therefore performed a systematic review and meta-analysis of proximal-to-distal sequencing in team handball throwing motions. A total of fourteen articles were included in the systematic review. Meta-analyses were performed for the timing of maximal angles and angular velocities as well as initiation of joint angular velocities in the penalty throw, the standing throw with run-up and the jump shot of experienced team handball players. For the initiation of joint angular velocities, the overall sequence was estimated to start with pelvis rotation, followed by trunk rotation, trunk flexion, shoulder internal rotation and elbow extension. For maximal velocities, the sequence started with pelvis rotation, followed by trunk rotation, trunk flexion, elbow extension, and shoulder internal rotation (post ball release). The obtained results were discussed in the light of talent identification purposes. Limitations to individual study methodology and of the present meta-analysis were also discussed. Much more research will be necessary, but at the very least, this review can provide a starting point for evidence-based discussions between movement scientists and team handball coaches to include proximal-to-distal sequencing as a measure of coordination to gauge early onset of talent.