The interchangeability of global positioning system and semiautomated video-based performance data during elite soccer match play.

In elite-level soccer, player motion characteristics are commonly generated from match play and training situations using semiautomated video analysis systems and global positioning system (GPS) technology, respectively. Before such data are used collectively to quantify global player load, it is necessary to understand both the level of agreement and direction of bias between the systems so that specific interventions can be made based on the reported results. The aim of this report was to compare data derived from both systems for physical match performances.

Changes in a top-level soccer referee's training, match activities, and physiology over an 8-year period: a case study.

Athlete case studies have often focused on the training outcome and not the training process. Consequently, there is a dearth of information detailing longitudinal training protocols, yet it is the combined assessment of both outcome and process that enhances the interpretation of physical test data. We were provided with a unique opportunity to assess the training load, physical match performance, and physiological fitness of an elite soccer referee from the referee's final season before attaining full-time, professional status (2002) until the season when he refereed the 2010 UEFA Champions League and FIFA World Cup finals.

Reduction in physical match performance at the start of the second half in elite soccer.

Purpose: Soccer referees' physical match performances at the start of the second half (46-60 min) were evaluated in relation to both the corresponding phase of the first half (0-15 min) and players' performances during the same match periods.

Methods: Match analysis data were collected (Prozone, UK) from 12 soccer referees on 152 English Premier League matches during the 2008/09 soccer season. Physical match performance categories for referees and players were total distance, high-speed running distance (speed >5.

The effect of superoxygenated water on blood gases, lactate, and aerobic cycling performance.

Context: Recently, superoxygenated-water beverages have emerged as a new purported ergogenic substance.

Purpose: This study aimed to determine the effects of superoxygenated water on submaximal endurance performance.

Methods: Eleven active male subjects, VO2max 52.

The effect of 15 consecutive days of heat-exercise acclimation on heat shock protein 70.

The purpose of this study was to investigate the alterations in serum heat shock protein (Hsp) 70 levels during a 15-consecutive-day intermittent heat-exercise protocol in a 29-year-old male ultra marathon runner. Heat acclimation, for the purpose of physical activities in elevated ambient temperatures, has numerous physiological benefits including mechanisms such as improved cardiac output, increased plasma volume and a decreased core temperature (T (c)). In addition to the central adaptations, the role of Hsp during heat acclimation has received an increasing amount of attention.

Hydration, thermoregulation, and performance effects of two sport drinks during soccer training sessions.

In the present study, we aimed to compare the thermoregulatory response and soccer-specific training performance aspects of two commercially available sport drinks, both of similar carbohydrate concentration, but one containing 5.2% glycerol. Ten players participated in two similar outdoor training sessions and were randomly assigned to each of two drinks: a carbohydrate (C) beverage or a carbohydrate-glycerol (CG) beverage.

Variation in basal heat shock protein 70 is correlated to core temperature in human subjects.

Heat shock proteins are highly conserved proteins and play an important chaperone role in aiding the folding of nascent proteins within cells. The heat shock protein response to various stressors, both in vitro and in vivo, is well characterised. However, basal levels of heat shock protein 70 (Hsp70) have not previously been investigated.

Inducible heat shock protein 70 and its role in preconditioning and exercise.

Heat shock proteins (Hsp) are well known to be expressed in response to a range of cellular stresses. They are known to convey protection against protein denaturation and a subsequent immediate stress. Inducible heat shock protein 70 (Hsp70) is among the most studied of these stress proteins and its role and function are discussed here in terms of thermal and in particular exercise preconditioning.

Physiological and mechanical response to soccer-specific intermittent activity and steady-state activity.

The aim of this study was to quantify response to a soccer-specific intermittent (INT) treadmill protocol based on notational analysis of match-play. Ten male semiprofessional football players (age 24.7 +/- 4.