Background

Static stretching is widely used to increase flexibility. However, there is no consensus regarding the optimal dosage parameters for increasing flexibility.

Objectives

We aimed to determine the optimal frequency, intensity and volume to maximise flexibility through static stretching, and to investigate whether this is moderated by muscle group, age, sex, training status and baseline level of flexibility.

Methods

Seven databases (CINAHL Complete, Cochrane CENTRAL, Embase, Emcare, MEDLINE, Scopus, and SPORTDiscus) were systematically searched up to June 2024. Randomised and non-randomised controlled trials investigating the effects of a single session (acute) or multiple sessions (chronic) of static stretching on one or more flexibility outcomes (compared to non-stretching passive controls) among adults (aged ≥ 18 years) were included. A multi-level meta-analysis examined the effect of acute and chronic static stretching on flexibility outcomes, while multivariate meta-regression was used to determine the volume at which increases in flexibility were maximised.

Results

Data from 189 studies representing 6654 adults (61% male; mean [standard deviation] age = 26.8 ± 11.4 years) were included. We found a moderate positive effect of acute static stretching on flexibility (summary Hedges’ g = 0.63, 95% confidence interval 0.52–0.75, p < 0.001) and a large positive effect of chronic static stretching on flexibility (summary Hedges’ g = 0.96, 95% confidence interval 0.84–1.09, p < 0.001). Neither effect was moderated by stretching intensity, age, sex or training status, or weekly session frequency and intervention length (chronic static stretching only) [p > 0.05]. However, larger improvements were found for adults with poor baseline flexibility compared with adults with average baseline flexibility (p = 0.01). Furthermore, larger improvements in flexibility were found in the hamstrings compared with the spine following acute static stretching (p = 0.04). Improvements in flexibility were maximised by a cumulative stretching volume of 4 min per session (acute) and 10 min per week (chronic).

Conclusions

Static stretching improves flexibility in adults, with no additional benefit observed beyond 4 min per session or 10 min per week. Although intensity, frequency, age, sex and training status do not influence improvements in flexibility, lower flexibility levels are associated with greater improvement following both acute and chronic static stretching. These guidelines for static stretching can be used by coaches and therapists to improve flexibility.

Clinical Trial Registration

PROSPERO CRD42023420168.

中文翻译：

---

优化静态拉伸的剂量以提高灵活性：系统评价、荟萃分析和多变量荟萃回归

 背景

静态拉伸被广泛用于增加柔韧性。然而，关于提高灵活性的最佳剂量参数尚未达成共识。

 目标

我们旨在确定最佳频率、强度和体积，以通过静态拉伸最大限度地提高柔韧性，并调查这是否受肌肉群、年龄、性别、训练状态和柔韧性基线水平的调节。

 方法

系统检索了截至 2024 年 6 月的 7 个数据库 （CINAHL Complete、Cochrane CENTRAL、Embase、Emcare、MEDLINE、Scopus 和 SPORTDiscus）。纳入了随机和非随机对照试验，这些试验调查了单次（急性）或多次（慢性）静态拉伸对成人（≥ 18 岁）的一个或多个柔韧性结局（与非拉伸被动对照相比）的影响。一项多水平荟萃分析检查了急性和慢性静态拉伸对柔韧性结局的影响，同时使用多变量荟萃回归来确定柔韧性增加最大化的量。

 结果

包括来自 189 项研究的数据，代表 6654 名成年人 （61% 为男性;平均 [标准差] 年龄 = 26.8 ± 11.4 岁）。我们发现急性静态拉伸对柔韧性有中等程度的积极影响（总结 Hedges' g = 0.63,95% 置信区间 0.52-0.75，p < 0.001）和慢性静态拉伸对柔韧性的较大积极影响（总结 Hedges' g = 0.96,95% 置信区间 0.84-1.09，p < 0.001）。 拉伸强度、年龄、性别或训练状态，或每周训练频率和干预时间（仅限慢性静态拉伸）均未调节这两种效果 [p > 0.05]。然而，与具有平均基线柔韧性的成年人相比，基线柔韧性差的成年人发现更大的改善 （p = 0.01）。此外，与急性静态拉伸后脊柱相比，腘绳肌的柔韧性改善更大 （p = 0.04）。每次 4 分钟（急性）和每周 10 分钟（慢性）的累积拉伸量可以最大限度地提高柔韧性的改善。

 结论

静态拉伸可以提高成人的柔韧性，每次训练 4 分钟或每周 10 分钟以上没有观察到额外的好处。尽管强度、频率、年龄、性别和训练状态不会影响柔韧性的改善，但较低的柔韧性水平与急性和慢性静态拉伸后更大的改善相关。教练和治疗师可以使用这些静态拉伸指南来提高柔韧性。

临床试验注册

 PROSPERO CRD42023420168。