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.

中文翻译：

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运动中的低能量可用性和相对能量缺乏：系统评价和荟萃分析

 介绍

当运动训练和身体机能的能量消耗超过热量摄入时，就会发生低能量可用性 （LEA）。这种不平衡会导致运动表现下降并增加受伤的风险。运动中的相对能量不足 （REDs） 是指当能量不足严重到足以导致代谢率、月经功能、免疫功能、骨骼健康、蛋白质合成和心血管功能发生变化时发生的一种情况。许多运动员，尤其是那些参加耐力、审美或重量级运动的运动员，会受到这种情况的不利影响。

 目标

本研究旨在确定运动员中 LEA 和 RED 的患病率，并首次对这些现象对运动表现和受伤风险的影响进行二次分析。

 方法

本系统综述已在 PROSPERO （CRD42023469253） 上注册。按照 PRISMA 指南使用 PubMed、Embase 和 Cochrane 在线数据库进行文献检索。纳入标准是讨论 LEA 或 REDs 患病率、LEA 或 REDs 对运动表现的影响或 LEA 或 REDs EA 对损伤影响的文章。

 结果

共有 59 项研究符合本荟萃分析的纳入标准，在 46 项不同的研究中，6118 名运动员中有 2737 名 （44.7%） 被确定患有 LEA，包括 44.2% 的女运动员和 49.4% 的男运动员。此外，在 8 项不同的研究中，730 名运动员中有 460 名 （63.0%） 被确定有患 RED 的风险。与能量可用性正常的运动员相比，患有 LEA 的运动员的跑步表现、训练反应、耐力表现、协调性、注意力、判断力、爆发力和敏捷性降低，并且因病缺勤的可能性增加。关于 LEA 是否总体上增加了受伤风险，研究结果喜忧参半。然而，大多数研究得出结论，患有 LEA 的运动员骨骼健康受损，骨应力损伤的风险更高。

 讨论

据我们所知，这是第一篇分析 LEA 和 REDs 对运动表现和受伤风险影响的系统综述。由于运动员中 LEA 的估计患病率很高，教练可能要考虑采用调查，例如女性低能量可用性问卷 （LEAF-Q） 来识别有 LEA 风险的运动员，因为早期识别和纠正 LEA 可以防止 REDs 症状的发展，降低骨骼健康受损和骨应力损伤的风险， 并帮助运动员优化训练中的表现优势。