小児における身体活動と腸内細菌叢（PA-Microbiome Kids） (PA-Microbiome)

実験的：MVPAプログラム

参加者は、週3回、1回あたり45〜60分間の、中程度から高強度の身体活動（MVPA）プログラムに16週間取り組みます。 各セッションには、ウォームアップ、有酸素ゲーム、自重を用いた筋力サーキットトレーニング、クールダウンが含まれ、訓練を受けたインストラクターの監督下で行われます。

行動：16週間の構造化された中強度身体活動プログラム

16週間にわたる構造化された中程度から高強度の身体活動プログラム。

他の：Attention Control + Waitlist

Participants engage in time-matched sedentary activities such as reading, science experiments, or crafts, three times per week, and are instructed to maintain their usual physical activity levels. After the 16-week trial period, they are offered a comparable MVPA program (waitlist).

行動：注意制御座位活動

時間を合わせた静的な活動、例えば読書、科学実験、またはクラフト。

複合体力Zスコアの変化

ベースラインから16週間後の複合体力zスコアの変化。 このスコアは「国家学生体力健康標準（2014年改訂版）」の年齢に適した項目と加重に基づいて計算されます。 尺度は、基準集団に基づく平均0、標準偏差1の標準化zスコアです。 理論上の上限または下限はありませんが、値は通常-3から+3の範囲です。 スコアが高いほど全体的な体力が優れていることを示します。

腸内細菌叢アルファ多様性の変化

腸内細菌叢のアルファ多様性指標（シャノン指数およびチャオ1指数）のベースラインから16週間後の変化を、16S rRNA遺伝子シーケンシングにより評価。 シャノン指数の最小値は0であり、理論上の最大値はありません。 チャオ1指数は種の豊富さを推定し、最小値は観察された種の数に等しく、理論上の最大値もありません。 両指標とも、値が高いほど多様性が高く、一般的に健康な腸内細菌叢を反映していると考えられます。

腸内細菌叢ベータ多様性の差異

MVPA群と対照群の腸内細菌叢コミュニティ構造（β多様性）の差異。 これは、Bray-CurtisおよびUniFrac距離行列を用いた順列多変量分散分析（PERMANOVA）によって評価される。 結果は、群割り付けによって説明されるコミュニティ構造の分散の割合を表すR二乗値、およびp値として報告される。 R二乗値が大きく、p値が小さいほど、群間の差異がより有意であることを示す。

体格指数（BMI）Zスコアの変化

ベースラインから16週間までの年齢・性別別BMI zスコアの変化。 これは、基準母集団に基づき平均が0となる標準化されたスコアで、理論上の上限または下限はありません。 スコアが高いほど、同年齢層と比較してBMIが高いことを示します。 健康体重に焦点を当てた本研究の文脈では、zスコアの増加は一般的により悪い結果と見なされます。

Heterogeneity of Treatment Effect Across Baseline PA×PF Quadrants

Heterogeneity of treatment effect (HTE) of the MVPA intervention on primary and secondary outcomes across the four pre-specified baseline phenotype groups (P1: low PA-low PF; P2: high PA-low PF; P3: low PA-high PF; P4: high PA-high PF) defined in the 2023 cross-sectional study. HTE will be assessed by including a Treatment × Baseline Quadrant interaction term in mixed-effects models. A statistically significant interaction (p < 0.05) would indicate that the intervention effect differs across baseline microbiome phenotypes. Effect sizes will be reported separately for each quadrant with 95% confidence intervals.

Baseline Microbial Taxa as Effect Modifiers of Intervention Response

Pre-specified analysis of whether baseline relative abundance (continuous, log-transformed) of Akkermansia, Faecalibacterium, Subdoligranulum, and Bacteroides coprocola modifies the MVPA intervention effect on composite physical fitness z-score and alpha diversity. Interaction terms (Treatment × Baseline Taxon Abundance) will be tested in mixed-effects models.

Change in Body Fat Percentage

Change from baseline to 16 weeks in body fat percentage. Higher values indicate greater adiposity.

Change in Waist Circumference and Waist-to-Hip Ratio

Change from baseline to 16 weeks in waist circumference (cm) and waist-to-hip ratio. Higher values indicate greater central adiposity.

Change in Resting Heart Rate

Change from baseline to 16 weeks in resting heart rate (beats per minute) measured after seated rest. Lower values generally indicate better cardiovascular fitness.

Change in Blood Pressure

Change from baseline to 16 weeks in resting systolic and diastolic blood pressure (mmHg).

Change in Vital Capacity

Change from baseline to 16 weeks in vital capacity (mL) measured by spirometry. Higher values indicate greater lung function.

Change in Stool Form and Defecation Frequency

Change from baseline to 16 weeks in stool form assessed by the Bristol Stool Form Scale (types 1 to 7) and in self-reported weekly defecation frequency.

Change in Resilience (CD-RISC-10)

Change from baseline to 16 weeks in resilience measured by the 10-item Connor-Davidson Resilience Scale. Scores range from 0 to 40; higher scores indicate greater resilience.

Change in Well-Being (WHO-5)

Change from baseline to 16 weeks in subjective well-being measured by the WHO-5 Well-Being Index. Raw scores (0 to 25) are transformed to a 0 to 100 scale; higher scores indicate better well-being.

Change in Anxiety Symptoms (SCARED)

Change from baseline to 16 weeks in anxiety symptoms measured by the child self-report Screen for Child Anxiety Related Emotional Disorders. Higher scores indicate more anxiety symptoms.

Change in Depressive Symptoms (CES-D)

Change from baseline to 16 weeks in depressive symptoms measured by the Center for Epidemiologic Studies Depression Scale. Higher scores indicate more depressive symptoms.

Change in Strengths and Difficulties (SDQ)

Change from baseline to 16 weeks measured by the Strengths and Difficulties Questionnaire. Higher total difficulties scores indicate more difficulties; higher prosocial subscale scores indicate more prosocial behaviour.

Change in Coping Style (SCSQ)

Change from baseline to 16 weeks in coping style measured by the Simplified Coping Style Questionnaire, reported as positive and negative coping subscale scores.

Change in Self-Concept

Change from baseline to 16 weeks in self-concept measured by an age-appropriate self-concept questionnaire for younger children. Higher scores indicate more positive self-concept.

Change in Emotion Regulation (ERQ-CA)

Change from baseline to 16 weeks in emotion regulation measured by the Emotion Regulation Questionnaire for Children and Adolescents, reported as cognitive reappraisal and expressive suppression subscale scores.

Change in Objective Sleep

Change from baseline to 16 weeks in accelerometer-derived sleep, including total sleep time and sleep efficiency.

Change in Physical Literacy

Change from baseline to 16 weeks in physical literacy measured by a physical literacy questionnaire. Higher scores indicate greater physical literacy.

Change in Exercise Self-Efficacy

Change from baseline to 16 weeks in exercise self-efficacy measured by an 18-item exercise self-efficacy questionnaire. Higher scores indicate greater self-efficacy.

Change in Dietary Self-Efficacy

Change from baseline to 16 weeks in dietary self-efficacy measured by a 16-item dietary self-efficacy questionnaire. Higher scores indicate greater self-efficacy.

Change in Physical Activity Enjoyment (PACES)

Change from baseline to 16 weeks in physical activity enjoyment measured by the Physical Activity Enjoyment Scale. Higher scores indicate greater enjoyment.

Change in Eating Behaviour (CEBQ)

Change from baseline to 16 weeks in eating behaviour measured by the Children's Eating Behaviour Questionnaire, reported by subscale.

Change in Executive Function and Attention

Change in Objective Physical Activity and Sedentary Time

Change from baseline to 16 weeks in accelerometer-derived moderate-to-vigorous physical activity (minutes per day) and sedentary time (minutes per day), used to verify intervention-induced change in activity.