# Four Minutes of Sprint Interval Training Had No Acute Effect on Improving Alertness, Mood, and Memory of Female Primary School Children and Secondary School Adolescents: A Randomized Controlled Trial PMID: 33467307 Journal: Journal of Functional Morphology and Kinesiology Published: 2020-12-14 Authors: Chua T, Aziz AR, Chia M ## Question Whether a 4-minute sprint interval training protocol of three 20-second all-out running shuttle sprints acutely improves self-reported alertness, mood, and memory recall in female primary school children and secondary school adolescents, and whether PE teachers view SIT-type activities as feasible in PE. ## Summary In an all-girl Singapore school setting, female primary school children and secondary school adolescents were randomized to a very brief running sprint interval session or a seated control condition. The sprint session used three 20-second all-out shuttle sprints with 60 seconds walking recovery, after a 3-minute warm-up, and was assessed acutely about 15 minutes later during the third PE lesson after familiarization. The protocol did not improve self-reported alertness, mood, or verbal memory recall compared with control, although adherence was high and teachers rated the format as feasible for PE. ## Population - Female primary school children and secondary school adolescents from one all-girl primary school and one all-girl secondary school in Singapore. - Sample size: 197 - Age: 9-10 years and 12-13 years - Sex: Female - Health status: School students; detailed health status not reported ## Methodology - Parallel randomized controlled study with 1:1 allocation, delivered during school PE lessons with acute pre-post assessment on the third session. - SIT delivered twice weekly for 3 weeks (6 sessions); acute outcomes assessed before and 11-20 minutes after the SIT condition during the third PE lesson. - Morning physical education lessons in one independent all-girl primary school and one independent all-girl secondary school in Singapore. - Randomized and controlled study design. ## Protocol - 3 x 20-second all-out running SIT. - Modality: 20-meter running shuttle sprints. - Work intervals: 20 seconds all-out. - Recovery: 60 seconds walking. - Sets or repetitions: 3. - Intensity: All-out effort; participants encouraged to match or better previous shuttle count. - Session duration: 4-minute SIT protocol; less than 8 minutes including 3-minute warm-up. - Frequency: Twice weekly. - Program length: 3 weeks; acute assessment during third PE lesson after two familiarization sessions. - Progression: Familiarization only; no dose progression reported. - Seated control. - Modality: Sitting and cheering. - Intensity: No SIT exercise. - Session duration: Same PE assessment context as SIT group. - Frequency: Same assessment schedule. - Program length: 3 weeks study context. ## Outcomes ### Alertness, mood, and memory recall overall Status: no clear change The 4-minute SIT protocol did not have a significant acute main effect on the combined learning-state outcomes in female children or adolescents. Children MANOVA F(3,59)=0.168, p=0.918, partial eta squared=0.008; adolescents F(3,127)=0.528, p=0.664, partial eta squared=0.012. ### Memory recall time effect Status: mixed Memory recall improved over time in female children and worsened over time in female adolescents, but these changes were not different between SIT and control groups. Children time effect F(1,127)=5.929, p=0.018, partial eta squared=0.089; adolescents time effect F(1,59)=12.801, p=0.001, partial eta squared=0.09; time x group p values >0.05. ### Exercise adherence Status: improved Most SIT participants completed all delivered SIT sessions. Primary school children 91.8 +/- 5.0%; secondary school adolescents 93.7 +/- 9.2%. ### Safety/injuries Status: no clear change No participants were reported to have sustained injuries from all-out sprints under qualified PE teacher supervision. ## Practical Insights - A 3 x 20-second all-out shuttle sprint format can fit into PE with total hard work of 1 minute and high attendance under trained teacher supervision. - This exact very brief SIT dose should not be framed as an evidence-backed acute enhancer of mood, alertness, or verbal memory in female youth. - Variety, timing, and baseline state may matter for school HIIT cognition or affect outcomes. ## Limitations - Female-only convenience sample from two schools. - Acute outcomes measured only once and only about 15 minutes post-condition. - No objective intensity data were reported. - Mood and alertness scales were single-item/self-constructed and not fully validated for this exact context. - A few classes missed sessions due to timetable constraints. - No male participants were studied. ## Safety And Adherence - No participants were reported to have sustained injuries from the all-out sprints under qualified PE teacher supervision. - Sick leave absences were reported as not related to the exercise. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/33467307/) (pubmed) - [DOI](https://doi.org/10.3390/jfmk5040092) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7804884/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.