Division of Training and Movement Sciences, Research Focus Cognition Sciences, University of Potsdam, Am Neuen Palais 10, Building 12, 14469, Potsdam, Germany.
School of Human Kinetics and Recreation, Memorial University of Newfoundland, St. John's, NF, Canada.
Sports Med. 2018 Sep;48(9):2067-2089. doi: 10.1007/s40279-018-0926-0.
Effects and dose-response relationships of balance training on measures of balance are well-documented for healthy young and old adults. However, this has not been systematically studied in youth.
The objectives of this systematic review and meta-analysis were to quantify effects of balance training (BT) on measures of static and dynamic balance in healthy children and adolescents. Additionally, dose-response relations for BT modalities (e.g. training period, frequency, volume) were quantified through the analysis of controlled trials.
A computerized systematic literature search was conducted in the electronic databases PubMed and Web of Science from January 1986 until June 2017 to identify articles related to BT in healthy trained and untrained children and adolescents.
A systematic approach was used to evaluate articles that examined the effects of BT on balance outcomes in youth. Controlled trials with pre- and post-measures were included if they examined healthy youth with a mean age of 6-19 years and assessed at least one measure of balance (i.e. static/dynamic steady-state balance, reactive balance, proactive balance) with behavioural (e.g. time during single-leg stance) or biomechanical (e.g. centre of pressure displacements during single-leg stance) test methods.
The included studies were coded for the following criteria: training modalities (i.e. training period, frequency, volume), balance outcomes (i.e. static and dynamic balance) as well as chronological age, sex (male vs. female), training status (trained vs. untrained), setting (school vs. club), and testing method (biomechanical vs. physical fitness test). Weighted mean standardized mean differences (SMD) were calculated using a random-effects model to compute overall intervention effects relative to active and passive control groups. Between-study heterogeneity was assessed using I and χ statistics. A multivariate random effects meta-regression was computed to explain the influence of key training modalities (i.e. training period, training frequency, total number of training sessions, duration of training sessions, and total duration of training per week) on the effectiveness of BT on measures of balance performance. Further, subgroup univariate analyses were computed for each training modality. Additionally, dose-response relationships were characterized independently by interpreting the modality specific magnitude of effect sizes. Methodological quality of the included studies was rated with the help of the Physiotherapy Evidence Database (PEDro) Scale.
Overall, our literature search revealed 198 hits of which 17 studies were eligible for inclusion in this systematic review and meta-analysis. Irrespective of age, sex, training status, sport discipline and training method, moderate to large BT-related effects were found for measures of static (SMD = 0.71) and dynamic (SMD = 1.03) balance in youth. However, our subgroup analyses did not reveal any statistically significant effects of the moderator variables age, sex, training status, setting and testing method on overall balance (i.e. aggregation of static and dynamic balance). BT-related effects in adolescents were moderate to large for measures of static (SMD = 0.61) and dynamic (SMD = 0.86) balance. With regard to the dose-response relationships, findings from the multivariate random effects meta-regression revealed that none of the examined training modalities predicted the effects of BT on balance performance in adolescents (R = 0.00). In addition, results from univariate analysis have to be interpreted with caution because training modalities were computed as single factors irrespective of potential between-modality interactions. For training period, 12 weeks of training achieved the largest effect (SMDwm = 1.40). For training frequency, the largest effect was found for two sessions per week (SMDwm = 1.29). For total number of training sessions, the largest effect was observed for 24-36 sessions (SMDwm = 1.58). For the modality duration of a single training session, 4-15 min reached the largest effect (SMDwm = 1.03). Finally, for the modality training per week, a total duration of 31-60 min per week (SMDwm = 1.33) provided the largest effects on overall balance in adolescents. Methodological quality of the studies was rated as moderate with a median PEDro score of 6.0.
Dose-response relationships were calculated independently for training modalities (i.e. modality specific) and not interdependently. Training intensity was not considered for the calculation of dose-response relationships because the included studies did not report this training modality. Further, the number of included studies allowed the characterization of dose-response relationships in adolescents for overall balance only. In addition, our analyses revealed a considerable between-study heterogeneity (I = 66-83%). The results of this meta-analysis have to be interpreted with caution due to their preliminary status.
BT is a highly effective means to improve balance performance with moderate to large effects on static and dynamic balance in healthy youth irrespective of age, sex, training status, setting and testing method. The examined training modalities did not have a moderating effect on balance performance in healthy adolescents. Thus, we conclude that an additional but so far unidentified training modality may have a major effect on balance performance that was not assessed in our analysis. Training intensity could be a promising candidate. However, future studies are needed to find appropriate methods to assess BT intensity.
对于健康的年轻和老年成年人，平衡训练对平衡措施的效果和剂量反应关系已有充分的记录。然而，这在年轻人中尚未得到系统研究。
本系统评价和荟萃分析的目的是量化平衡训练（BT）对健康儿童和青少年静态和动态平衡措施的影响。此外，通过对对照试验的分析，量化了 BT 方式（例如训练期、频率、量）的剂量-反应关系。
在电子数据库 PubMed 和 Web of Science 中进行了计算机系统的文献检索，以查找与健康训练和未训练的儿童和青少年的 BT 相关的文章，检索时间从 1986 年 1 月至 2017 年 6 月。
采用系统方法评估了 BT 对年轻人平衡结果的影响的文章。如果研究使用行为（例如单腿站立时间）或生物力学（例如单腿站立时的中心压力位移）测试方法评估了健康青年，其平均年龄为 6-19 岁，且评估了至少一项平衡措施（即静态/动态稳态平衡、反应性平衡、主动性平衡），则纳入了有预测量和后测量的对照试验。
对纳入的研究进行了以下标准编码：训练方式（即训练期、频率、量）、平衡结果（即静态和动态平衡）以及年龄、性别（男性与女性）、训练状态（训练与未训练）、地点（学校与俱乐部）和测试方法（生物力学与体能测试）。使用随机效应模型计算了加权平均标准化均数差（SMD），以计算相对于主动和被动对照组的总体干预效果。使用 I 和 χ 统计量评估了研究间的异质性。计算了多元随机效应荟萃回归，以解释关键训练方式（即训练期、训练频率、总训练次数、训练课持续时间和每周训练总时长）对 BT 对平衡表现的影响。此外，还针对每种训练方式进行了单变量亚组分析。此外，通过解释效应量的特定幅度，独立地描述了剂量反应关系。使用物理治疗证据数据库（PEDro）量表对纳入研究的方法学质量进行了评分。
总的来说，我们的文献检索显示有 198 个结果，其中 17 项研究符合纳入本系统评价和荟萃分析的标准。无论年龄、性别、训练状态、运动学科和训练方法如何，BT 与静态（SMD=0.71）和动态（SMD=1.03）平衡的措施都有中度到高度的关联。然而，我们的亚组分析并没有发现年龄、性别、训练状态、地点和测试方法等调节变量对整体平衡（即静态和动态平衡的综合）有任何统计学显著的影响。青少年的 BT 相关效果在静态（SMD=0.61）和动态（SMD=0.86）平衡方面为中度到高度。关于剂量-反应关系，多元随机效应荟萃回归的结果表明，在青少年中，没有任何检查的训练方式可以预测 BT 对平衡表现的影响（R=0.00）。此外，由于训练方式是作为单一因素计算的，因此需要谨慎解释单变量分析的结果，因为没有考虑潜在的训练方式之间的相互作用。对于训练期，12 周的训练达到了最大的效果（SMDwm=1.40）。对于训练频率，每周两次训练的效果最大（SMDwm=1.29）。对于总训练次数，24-36 次训练的效果最大（SMDwm=1.58）。对于单次训练课的持续时间，4-15 分钟的效果最大（SMDwm=1.03）。最后，对于每周的训练频率，每周 31-60 分钟的训练频率提供了青少年整体平衡的最大效果（SMDwm=1.33）。研究的方法学质量被评为中等，PEDro 评分中位数为 6.0。
剂量-反应关系是独立计算的（即针对特定的训练方式），而不是相互依存的。由于纳入的研究没有报告训练强度，因此没有考虑训练强度来计算剂量-反应关系。此外，纳入的研究数量仅允许对青少年的整体平衡进行剂量-反应关系的特征描述。此外，我们的分析显示出相当大的研究间异质性（I=66-83%）。由于其初步状态，应谨慎解释此荟萃分析的结果。
BT 是提高平衡表现的有效手段，对健康年轻人的静态和动态平衡具有中度到高度的效果，无论年龄、性别、训练状态、地点和测试方法如何。检查的训练方式对健康青少年的平衡表现没有调节作用。因此，我们的结论是，目前尚未评估的额外但可能是未知的训练方式可能对平衡表现有重大影响。训练强度可能是一个有前途的候选者。然而，需要进一步的研究来找到评估 BT 强度的适当方法。
