Sports Medicine最新文献

Optimal loading involves the prescription of an exercise stimulus that promotes positive tissue adaptation, restoring function in patients undergoing rehabilitation and improving performance in healthy athletes. Implicit in optimal loading is the need to monitor the response to load, but what constitutes a normal response to loading? And does it differ among tissues (e.g., muscle, tendon, bone, cartilage) and systems? In this paper, we discuss the “normal” tissue response to loading schema and demonstrate the complex interaction among training intensity, volume, and frequency, as well as the impact of these training variables on the recovery of specific tissues and systems. Although the response to training stress follows a predictable time course, the recovery of individual tissues to training load (defined herein as the readiness to receive a similar training stimulus without deleterious local and/or systemic effects) varies markedly, with as little as 30 min (e.g., cartilage reformation after walking and running) or 72 h or longer (e.g., eccentric exercise-induced muscle damage) required between loading sessions of similar magnitude. Hyperhydrated and reactive tendons that have undergone high stretch–shorten cycle activity benefit from a 48-h refractory period before receiving a similar training dose. In contrast, bone cells desensitize quickly to repetitive loading, with almost all mechanosensitivity lost after as few as 20 loading cycles. To optimize loading, an additional dose (≤ 60 loading cycles) of bone-centric exercise (e.g., plyometrics) can be performed following a 4–8 h refractory period. Low-stress (i.e., predominantly aerobic) activity can be repeated following a short (≤ 24 h) refractory period, while greater recovery is needed (≥ 72 h) between repeated doses of high stress (i.e., predominantly anaerobic) activity. The response of specific tissues and systems to training load is complex; at any time, it is possible that practitioners may be optimally loading one tissue or system while suboptimally loading another. The consideration of recovery timeframes of different tissues and systems allows practitioners to determine the “normal” response to load. Importantly, we encourage practitioners to interpret training within an athlete monitoring framework that considers external and internal load, athlete-reported responses, and objective markers, to contextualize load–response data.

Everyday human interactions require observers to anticipate the actions of others (e.g., when walking past another in a corridor or choosing where to hit a ground stroke in tennis). Yet, experimental paradigms that aim to examine anticipation continue to use simplistic designs that are not interactive and therefore fail to account for the real-life, social nature of these interactions. Here we propose a fundamental, paradigmatic shift toward a "dynamic interactive anticipation" paradigm that models real-life interactions. We propose that it will change the way behavioral experimentalists study anticipation and spark theory development by unravelling the mechanisms underlying anticipation in real-time interactions.

Background and aim: Professional soccer players' self-reported dietary intakes often do not meet recommended sport nutrition guidelines. Although behaviour change models have previously explored barriers and enablers to nutritional adherence, the cultural factors influencing players' nutritional habits also warrant investigation. Accordingly, we aimed to explore players' perceptions of the nutrition culture within the professional soccer environment.

Methods: An interpretivist paradigm, which emphasises that reality is subjectively and socially constructed, underpins this study. Qualitative, face-to-face semi-structured interviews (comprising open-ended questions) were conducted with purposively sampled male soccer players from the English Premier League (EPL) (five British, five migrant; mean age: 26 ± 6 years; mean EPL appearances: 106 ± 129). Data were abductively analysed using thematic analysis according to Bourdieu's concepts of habitus, capital, field and doxa practices.

Results: This study revealed five key themes: (1) players' habitus, as shaped by familial, ethnic and religious backgrounds, influences their dietary habits; (2) social capital, via managers (head coaches), teammates and online influences, impact players' dietary practices; (3) the increase in both soccer clubs' and players' economic capitals has advanced nutrition provision; (4) an unequal distribution of economic capitals has led to hierarchical practice in the performance nutrition field with personalised nutrition being somewhat enacted at the higher levels; and (5) body composition measurement is a 'doxic' practice in professional soccer that warrants challenge.

Conclusions: Soccer players' habitual nutritional practices are influenced by personal upbringing and the club context, including economic resources and social capital from managers. The performance nutrition field within professional soccer is also shaped by stakeholders' doxic beliefs surrounding the perceived optimal body composition of players, with managers exerting social capital.

Background: Although the efficacy of interval training for improving body composition has been summarized in an increasing number of systematic reviews in recent years, discrepancies in review findings and conclusions have been observed.

Objective: This study aims to synthesize the available evidence on the efficacy of interval training compared with moderate-intensity continuous training (MICT) and nonexercise control (CON) in reducing body adiposity in apparently healthy adults.

Methods: An umbrella review with meta-analysis was performed. A systematic search was conducted in seven databases (MEDLINE, EMBASE, Cochrane Database, CINAHL, Scopus, SPORTDiscus, and Web of Science) up to October 2023. Systematic reviews with meta-analyses of randomized controlled trials (RCTs) comparing interval training and MICT/CON were included. Literature selection, data extraction, and methodological quality assessment (AMSTAR-2) were conducted independently by two reviewers. Meta-analyses were performed using a random-effects model. Subgroup analyses were conducted based on the type of interval training [high-intensity interval training (HIIT) and sprint interval training (SIT)], intervention duration, body mass index, exercise modality, and volume of HIIT protocols.

Results: Sixteen systematic reviews, including 79 RCTs and 2474 unique participants, met the inclusion criteria. Most systematic reviews had a critically low (n = 6) or low (n = 6) AMSTAR-2 score. Interval training demonstrated significantly greater reductions in total body fat percent (BF%) compared with MICT [weighted mean difference (WMD) of - 0.77%; 95% confidence interval (CI) - 1.12 to - 0.32%] and CON (WMD of - 1.50%; 95% CI - 2.40 to - 0.58%). Significant reductions in fat mass, visceral adipose tissue, subcutaneous abdominal fat, and android abdominal fat were also observed following interval training compared to CON. Subgroup analyses indicated that both HIIT and SIT resulted in superior BF% loss than MICT. These benefits appeared to be more prominent in individuals with overweight/obesity and longer duration interventions (≥ 12 weeks), as well as in protocols using cycling as a modality and low-volume HIIT (i.e., < 15 min of high-intensity exercise per session).

Conclusions: This novel umbrella review with large-scale meta-analysis provides an updated synthesis of evidence with implications for physical activity guideline recommendations. The findings support interval training as a viable exercise strategy for reducing adiposity in the general population.

In this opinion piece I reiterate the concepts of near and far transfer as previously described in the psychological literature. I show that despite very limited evidence, many technologies, tools and methods make questionable claims of eliciting far transfer from generic perceptual and/or cognitive training to sports performance. Specifically, this commentary illustrates with studies on stroboscopic vision, neurofeedback training and executive functions that the claims made for the beneficial effects of these training methods are currently unsubstantiated. I conclude that greater scrutiny by researchers is needed in order to assist practitioners to make better-informed decisions about tools, methods and technologies that may aid sports performance.

Introduction

Low energy availability (LEA) occurs when energy expenditure from athletic training and bodily functions exceeds caloric intake. This imbalance results in declines in athletic performance and increases the risk of injury. Relative energy deficiency in sport (REDs) is a condition that occurs when the energy deficit is severe enough to cause alterations to metabolic rate, menstrual function, immune function, bone health, protein synthesis, and cardiovascular function. Many athletes, particularly those competing in endurance, aesthetic, or weight-class sports, are adversely impacted by this condition.

Objectives

This study aims to determine the prevalence of LEA and REDs among athletes and present the first secondary analysis of the impacts of these phenomena on sports performance and risk of injury.

Methods

This systematic review was registered on PROSPERO (CRD42023469253). Literature searches were performed following PRISMA guidelines using PubMed, Embase, and Cochrane online databases. Inclusion criteria were articles discussing the prevalence of LEA or REDs, the impact of LEA or REDs on athletic performance, or the impact of LEA or REDs EA on injury.

Results

A total of 59 studies met the inclusion criteria for this meta-analysis, and 2737 of 6118 athletes (44.7%) in 46 different studies were determined to have LEA, including 44.2% of female athletes and 49.4% of male athletes. In addition, 460 of 730 athletes (63.0%) in eight different studies were determined to be at risk of REDs. Athletes with LEA were found to have decreased run performance, training response, endurance performance, coordination, concentration, judgment, explosive power, and agility relative to athletes with normal energy availability, as well as an increased likelihood of absence from training due to illness. Studies had mixed results as to whether LEA increased the risk of injury in general. However, most studies concluded that athletes with LEA have impaired bone health and a higher risk of bone stress injuries.

Discussion

To our knowledge, this is the first systematic review analyzing the impacts of LEA and REDs on athletic performance and risk of injury. Due to the high estimated prevalence of LEA among athletes, coaches may want to consider employing surveys such as the low energy availability in females questionnaire (LEAF-Q) to identify athletes at risk for LEA, as early identification and correction of LEA can prevent the development of symptoms of REDs, reduce the risk of impaired bone health and bone stress injuries, and help athletes optimize the performance benefits from their training.

The increasing legalization of Cannabis sativa plant products has sparked growing interest in their therapeutic applications. Prohibition laws established in 1937 hindered formal research on cannabis, a plant with cultural and medicinal roots dating back to 2700 BC in Chinese history. Despite regulatory hurdles, published research on cannabis has emerged; yet elite athletes remain an underrepresented population in these studies. Athletes, known for exploring diverse substances to optimize performance, are drawn to the potential benefits of cannabinoid therapy, with anecdotal reports suggesting positive effects on issues ranging from anxiety to brain injuries. This review aims to evaluate empirical published cannabis research with a specific focus on its potential applications in athletics. The changing legal landscape, especially the removal of cannabis from drug testing programs in leagues such as the National Basketball Association (NBA), and endorsements by Major League Baseball (MLB) for cannabinoid products and the National Football League (NFL) for cannabis research, reflects a shift in the acceptability of such substances in sports. However, stigma, confusion, and a lack of education persist, hindering a cohesive understanding among sports organizations, including business professionals, policymakers, coaches, and medical/training staff, in addition to athletes themselves. Adding to the confusion is the lack of consistency with cannabinoid regulations from sport to sport, within or out of competition, and with cannabis bioactive compounds. The need for this review is underscored by the evolving attitudes toward cannabinoids in professional sports and the potential therapeutic benefits or harms they may offer. By synthesizing current cannabis research, this review aims to provide a comprehensive understanding of the applications and implications of cannabinoid use in the realm of athletics.