The purposes of this study are (a) to examine the effects of contact time manipulation on jump parameters and (b) to examine the interaction between starting height changes and contact time changes on important jump parameters. Fifteen male athletes performed a series of drop jumps from heights of 20, 40, ...

In order to validate the use of heart rate (HR) in describing and monitoring physiological demands during soccer activities, the HR versus oxygen uptake ( V(.)O(2)) relationship determined on the field during soccer-specific exercises was compared to that found in the laboratory during treadmill exercise. Seven male amateur soccer players ...

The aim of this study was to compare the effects of plyometric training performed with rapid or slow stretch contraction on jump performance and muscle properties. Thirty males between the ages of 19 and 22 volunteered for the 8-week experiment. Subjects were divided into the following three groups: training group ...

This study measured fluid balance during a 90-min preseason training session in the first team squad (24 players) of an English Premier League football team. Sweat loss was assessed from changes in body mass after correction for ingested fluids and urine passed. Sweat composition was measured by collection from patches ...

BACKGROUND: A high level of strength is inherent in elite soccer play, but the relation between maximal strength and sprint and jumping performance has not been studied thoroughly. OBJECTIVE: To determine whether maximal strength correlates with sprint and vertical jump height in elite male soccer players. METHODS: Seventeen international male ...

The purpose of this study was to investigate the acute effects of a heavy dynamic preload, consisting of 1 set of 5 repetition maximum (5RM) back squats, on countermovement vertical jump (VJ) and horizontal jump (HJ) performance. The study also investigated the ability of subjects to learn to apply the ...

The Prisoner's Dilemma game is widely used to investigate how cooperation between unrelated individuals can evolve by natural selection. In this game, each player can either 'cooperate' (invest in a common good) or 'defect' (exploit the other's investment). If the opponent cooperates, you get R if you cooperate and T ...

OBJECTIVES: To determine the effects of exercise training on physical condition in 25 college rugby players during a summer training camp, and to compare these variables by the different players' positions. METHODS: Changes in body composition parameters and blood biochemistry were examined before and after a summer training camp. RESULTS: ...

OBJECTIVE: To evaluate the effects of plyometric training on muscle-activation strategies and performance of the lower extremity during jumping exercises. SUBJECTS: Twenty healthy National Collegiate Athletic Association Division I female athletes. DESIGN AND SETTING: A pretest and posttest control group design was used. Experimental subjects performed plyometric exercises 2 times ...

AIM: The aims of the current study were, firstly, to quantify the motion characteristics of professional youth soccer players and, secondly, to develop and validate a soccer-specific exercise protocol (SSEP). METHODS: The motion characteristics of 12 first team members and 12 scholars (under 19s), signed to an English Premiership club ...

AIM: Changes in leucocyte and monocyte subpopulations were investigated in 10 elite male soccer players aged 16-19 years. The purpose was to perform a descriptive study of immunological alterations in elite soccer players in response to two consecutive games separated by 20 h. It was hypothesized that in response to ...

As a consequence of the physiological demands experienced during a competitive soccer season, the antagonistic relationship between anabolic and catabolic processes can affect performance. Twenty-five male collegiate soccer players were studied throughout a season (11 weeks) to investigate the effects of long-term training and competition. Subjects were grouped as starters ...

OBJECTIVE: To determine prevalence of Exercise-induced Bronchospasm (EIB) in hockey players, who had represented or were aspiring to represent Pakistan at international level. METHOD: An observational, cross-sectional study was done on the prevalence of EIB in national hockey players of Pakistan. All participants of the training camp (n = 27) ...

BACKGROUND: It is well established that physical activity is beneficial to health. For the individual in a wheelchair, a regular exercise program might not be available or may be too difficult to participate in physically and/or psychologically. Many exercise devices and regimes are boring. The goal, therefore, is to develop ...

PURPOSE: The purpose of this study was to examine aerobic demands and activity patterns during match play in young soccer players with respect to competition level, age, and biological maturity. METHODS: Ten nonelite players (NbP) and nine elite players (EbP) in their early puberty (12 yr), and seven elite players ...

The purpose of this study was to compare triple (T) and quadruple (Q) toe-loop figure skating jumps and quantify basic characteristics of these jumps to provide information to coaches that will assist them in teaching quadruple toe-loops to elite figure skaters. High-speed video was taken during men's practice and competition ...

BACKGROUND: Early intervention teams attempt to improve outcome in schizophrenia through earlier detection and the provision of phase-specific treatments. Whilst the number of early intervention teams is growing, there is a lack of clarity over their essential structural and functional elements. METHODS: A 'Delphi' exercise was carried out to identify ...

PURPOSE: The objective of this study was to theoretically model, based on the Hertz contact theory, the impact force and contact time, as well as the linear and angular head accelerations during heading in children using two neck stiffness conditions (infinite and negligible stiffness). METHODS: The following mathematical model inputs ...

We examined changes in the haematological, metabolic, immunological, hormonal, and psychological fields using selected variables in 20 professional soccer players. over the course of a competitive season. The team performance was assessed by computing the winning percentage. A symptom checklist was used to assess the severity of upper respiratory tract ...

Little is known about the effects of exercise on cognitive function, but in a biathlon it is known that intense skiing exercise decreases shooting performance. So the present study was designed to assess the cognitive origin of this decrease by examining the influence of skiing exercise on perceptual estimation and ...

AIM: The aim of the present study was to determine the effect of tropical climate (i.e., hot and humid) on performance during multiple jump-and-reach tests. METHODS: Fourteen male basketball players volunteered to perform 2 randomized series of jump-and-reach tests, which consisted of a jump-and-reach test every 15 sec for 5 ...

AIM: In order to measure game intensity in female basketball players, 2 teams (Olympic National Team - I -and a team at 1(st) National Division - N) were studied for a total of 12 games (10 official competitions and 2 practice games -P). METHODS: Both blood lactate concentration ([La](b)) and ...

Fatigue represents a reduction in the capability of muscle to generate force. The aim of the present study was to establish the effects of exercise that simulates the work rate of competitive soccer players on the strength of the knee extensors and knee flexors. Thirteen amateur soccer players (age 23.3+/-3.9 ...

The effect of 3 warm-up routines on standing broad jump (SBJ) performance was investigated. Thirty-two men and women participated as subjects. Following the determination of 1-repetition maximum (1RM) squat, subjects completed warm-up routines and broad jumps on 4 occasions in a randomized order. Subjects performed SBJ immediately (POST) and 15 ...

BACKGROUND: Repeated impacts by heading might lead to significant head injuries in soccer players comparable to those of patients with accidental minor traumatic brain injury (TBI). The neuroprotein S-100B released into the circulation is suggested to be a reliable marker indicating brain damage. The objective was to evaluate the neuroprotein ...

INTRODUCTION: Acupuncture is used to modulate the physical well-being of athletes in Asian countries. However, there is little information on the immediate effects of acupuncture treatment on physiological or psychological responses to exercise. PURPOSE: The purpose of this study was to examine the effect of acupuncture treatment on the physical ...

The primary purpose of this study was to evaluate whether a preseason strength training programme for the hamstring muscle group - emphasising eccentric overloading - could affect the occurrence and severity of hamstring injuries during the subsequent competition season in elite male soccer players. Thirty players from two of the ...

This study tested the hypothesis that neuromuscular characteristics of plantar flexor (PF) and knee extensor (KE) muscles explain differences of both performance in vertical jump and maximal voluntary isometric contraction (MVC) between endurance-trained (END, n = 9), power-trained (POW, n = 8), and sedentary subjects (SED, n = 8). Evoked ...

The aims of this study were to determine how custom-fit compression shorts affect athletic performance and to examine the mechanical properties of the shorts. Ten male and 10 female track athletes on a university's nationally competitive track team, specializing in sprint or jump events, participated in the study. Testing utilized ...

In this study, we examined the relationships between body sway, aim point fluctuation and performance in rifle shooting on an inter- and intra-individual basis. Six elite shooters performed 20 shots under competition conditions. For each shot, body sway parameters and four aim point fluctuation parameters were quantified for the time ...

This study evaluated the body composition (underwater weighing) and cardiorespiratory function (VO(2)max and O(2)debt max measured by the treadmill exercise test) in 12 members of the women's volleyball team (mean age 17.4 years) and 11 members of the women's basketball team (mean age 17.6 years) that won the championship in ...

The aim of this study was to develop an exercise protocol to simulate tennis matchplay on a 'category 2' surface. Match analyses were used to form the basis for the design of the protocol. The protocol involved playing against a tennis ball serving machine. Part A of the protocol comprised ...

PURPOSE: It is generally agreed that vertical prism bar training can increase vertical fusion amplitude. However, little is known as to whether the increased vertical fusion amplitude following vergence exercise is due to improvement of the sensory or the motor system or both. The main aim of the present study ...

Complex training has been recommended as a method of incorporating plyometrics with strength training. Some research suggests that plyometric performance is enhanced when performed 3-4 minutes after the strength training set, whereas other studies have failed to find any complex training advantage when plyometrics are performed immediately after the strength ...

The purpose of the current research was to study the effect of a warm-up program including submaximal half-squats on vertical jumping ability. Twenty physically active men participated in the study. Each subject performed 5 sets of half-squats with 2 repetitions at each of the following intensities: 20, 40, 60, 80, ...

The purpose of this study was to evaluate changes in soccer-specific power endurance of 34 female high school soccer players throughout a season either with or without an intermittent, high-intensity exercise protocol. Thirty-four female high school soccer players were tested prior to the 2000 fall season and again 10 weeks ...

Tennis played at an elite level requires intensive training characterized by repeated bouts of brief intermittent high intensity exercise over relatively long periods of time (1 - 3 h or more). Competition can place additional stress on players. The purpose of this study was to investigate the temporal association between ...

AIM: The interaction between running, stretching and practice jumps during warm-up for jumping tests has not been investigated. The purpose of the present study was to compare the effects of running, static stretching of the leg extensors and practice jumps on explosive force production and jumping performance. METHODS: Sixteen volunteers ...

The purpose of this study was to examine the relation between exercise intensity and immune function. Ten healthy young males underwent a constant work rate exercise of three levels, 90%, 80% and 70% ventilatory threshold (VT) work rate, for 20 min on a bicycle ergometer. These work rates were calculated ...

The aim of this study was to investigate the effect of acute and regular exercise on somatosensory-evoked potentials (SEP). The study group was designed as 9 female and 7 male volleyball players, and the control group as 9 female and 7 male sedentary students. The P1 and P2 latency and ...

AIM: The aim of this study was to investigate whether a single soccer specific fitness test (SSFT) could differentiate between highly trained and recreationally active soccer players in selected test performance indicators. METHODS: Subjects: 13 Academy Scholars (AS) from a professional soccer club and 10 Recreational Players (RP) agreed to ...

Deviations from perfect bilateral symmetry, in a normally symmetric organism, signal a lack of developmental precision. In adult human males, previous studies have shown that symmetry is positively associated with height, body mass and physical performance. In this study, symmetry was measured in adult male athletes from two sports, competing ...

Matching is used to control for imbalances between groups, but the preferable strategy for matching is not always clear. We sought to compare two algorithms-optimal matching with a fixed number of controls (OMFC), and optimal matching with a variable number of controls (OMVC). We compared the degree of bias reduction ...

Sport scientists have devoted relatively little attention to soccer penalty kicks, despite their decisive role in important competitions such as the World Cup. Two possible kicker strategies have been described: ignoring the goalkeeper action (open loop) or trying to react to the goalkeeper action (closed loop). We used a paradigm ...

OBJECTIVE: To describe the characteristics of badminton in order to determine the energy requirements, temporal structure, and movements in the game that indicate performance level. To use the findings to plan training with greater precision. METHODS: Eleven badminton players (mean (SD) age 21.8 (3.26) years) with international experience from four ...

INTRODUCTION: In professional rugby, different positional roles may require different levels of aerobic fitness. Forward and backline players from a team of elite rugby players were tested to evaluate the differences between the two groups. METHODS: 28 male players, 15 backs and 13 forwards, underwent maximal treadmill cardiopulmonary exercise testing ...

OBJECTIVES: We examined the echocardiographic characteristics of highly trained American football players. BACKGROUND: Intense physical training is associated with morphologic and physiologic cardiac changes often referred to as the "athlete's heart." Echocardiographic features peculiar to elite football players have not been described. METHODS: We studied cardiac morphology and function as ...

In a double-blind, randomized, placebo-controlled study, we investigated the effect of 8 weeks of supplementation with bovine colostrum (Intact) on body composition and exercise performance (5 x 10-m sprint, vertical jump, shuttle-run test, and suicide test). Seventeen female and 18 male elite field hockey players, including players from the Dutch ...

To determine the movement patterns and physiological demands of top-class soccer assistant referees, we performed computerized time-motion analysis and measured heart rate and blood lactate concentration in 15 assistant referees during 22 competitive matches in the top Danish league. To relate match performance to the physical capability of the assistant ...

PURPOSE: This study represents the first time that anaerobic power performance was examined during an actual intercollegiate American football game. In addition, biochemical and endocrine responses also were examined to assess the physiological stress imposed by this competitive contest. METHODS: Twenty-one members of a NCAA Division III football team were ...